Co-reporter:D.G. Wang, W.L. Zhang, H.J. Li, J.H. Zhang, C.Z. Chen
Ceramics International 2017 Volume 43(Issue 1) pp:672-676
Publication Date(Web):January 2017
DOI:10.1016/j.ceramint.2016.09.213
Abstract
HA/BG composite films have been deposited on Ti-6Al-4V by pulse laser under O2 atmosphere, and EPMA-EDS, SEM, XRD, FTIR measurements have been performed. Under O2 atmosphere, the crystallinity of the deposited films increases and Ca/P atomic ratio slightly decreases with increasing the substrate temperature. When the film was deposited at 600 °C, the film was compact and crystalline HA was observed. Comparing with Ar atmosphere, O2 atmosphere is benefical for decreasing Ca/P atomic ratio of the films, and the in vivo test indicates that the film obtained under O2 atmosphere has excellent osteoinductivity. So O2 atmosphere is a promise alternative atmosphere to fabricate HA/BG composite films by pulsed laser deposition.
Co-reporter:Jinhe Dou;Yang Chen;Yiming Chi;Huancai Li;Guochao Gu
Physical Chemistry Chemical Physics 2017 vol. 19(Issue 23) pp:15110-15119
Publication Date(Web):2017/06/14
DOI:10.1039/C7CP02672B
Magnesium alloys are the most promising implant materials due to their excellent biodegradability. However, their high degradation rate limits their practical application. In this study, we produced a calcium–phosphate (Ca–P) coating and a calcium–phosphate–silicon (Ca–P–Si) coating via one-step and two-step micro-arc oxidation processes, respectively. The microstructure and chemical composition of the MAO coatings were characterized using SEM, XRD and EDS. The degradation behaviors of the MAO coatings and the substrate were investigated using electrochemical techniques and immersion tests in simulated body fluid (SBF). The results show that the silicate was successfully incorporated into the Ca–P coating in the second MAO step, and this also increased the thickness of the coating. The Ca–P–Si coatings remarkably reduced the corrosion rate of the Mg alloy and Ca–P coating during 18 days of immersion in SBF. In addition, the bone-like apatite layer on the sample surface demonstrated the good biomineralization ability of the Ca–P–Si coating. Potentiodynamic polarization results showed that the MAO coating could clearly enhance the corrosion resistance of the Mg alloy. Moreover, we propose the growth mechanism of the MAO coating in the second step.
Co-reporter:Jinhe Dou, Guochao Gu, Chuanzhong Chen
Materials Letters 2017 Volume 196(Volume 196) pp:
Publication Date(Web):1 June 2017
DOI:10.1016/j.matlet.2017.03.028
•A porous bioceramic CaP coating was prepared by micro-arc oxidation.•The CaP coatings exhibited better bioactivity than substrate.•The MAO coatings enhanced the corrosion resistance of the Mg alloy.Micro-arc oxidation (MAO) in an alkaline disodium hydrogen phosphate electrolyte containing different calcium salts has been used to produce oxide coatings on self-designed Mg-2Zn-1Ca-0.8 Mn alloy as a potential biodegradable bone implant material. SEM with EDS, XRD and FT-IR were used to characterize microstructures, elemental distribution and compositions of the MAO coatings. Potentiodynamic polarization curves and corrosion morphologies of the coating in the SBF solution are also presented. The results show that the coatings formed in (CH3COO)2Ca-containing electrolyte exhibit better apatite-inducing ability. However, the coatings formed in Ca(C6H11O7)2·H2O-containging electrolyte show lower corrosion resistance than those formed in (CH3COO)2Ca and (C6H5O7)2Ca3·4H2O containing electrolyte.Surface morphology and EDS results of the samples after 21 days immersion in SBF solution: (a) C1, (b) C2, (c) C3 coating and (d) Mg substrate.Download high-res image (342KB)Download full-size image
Co-reporter:Fei Weng, Huijun Yu, Chuanzhong Chen, Jianli Liu, Longjie Zhao, Jingjie Dai
Journal of Alloys and Compounds 2016 Volume 686() pp:74-81
Publication Date(Web):25 November 2016
DOI:10.1016/j.jallcom.2016.05.319
•Metal matrix composite coatings were fabricated by laser cladding Co42+TiN.•The composite coating showed metallurgical bonding with the substrate.•Micro-hardness and wear resistance were enhanced notably.•More TiN addition was beneficial to the improvement of wear resistance.•In situ formed TiC tended to grow around the TiN in the molten pool.In this study, composite coatings were fabricated on Ti-6Al-4V alloy by laser cladding with Co42 Co-based self-fluxing alloy and TiN mixed powders. Microstructures and wear resistance of the cladding coatings with 20 wt% and 30 wt% TiN addition were investigated comparatively. The composite coatings were mainly comprised of γ-Co/Ni, CoTi, CoTi2, Co3Ti, NiTi, TiN, CrB, Cr7C3, TiC, TiB, and TiC0.3N0.7 phases. The composite phase components were beneficial to the improvement of the micro-hardness and wear resistance. Results showed that the micro-hardness of the composite coatings was 3–4 times the Ti-6Al-4V substrate and the wear resistance was enhanced as high as 18.2 times. With more TiN addition, the micro-hardness and wear resistance of the laser cladding coating were improved further. The microstructure, strengthening mechanism, and wear mechanism of the laser cladding coatings were investigated accordingly.
Co-reporter:Huijun Yu, Qing Dong, Jinhe Dou, Yaokun Pan, Chuanzhong Chen
Applied Surface Science 2016 Volume 388(Part A) pp:148-154
Publication Date(Web):1 December 2016
DOI:10.1016/j.apsusc.2016.02.051
Highlights
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Bioactive ceramic coatings formed on the ZK61 alloy surface.
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MAO coating with low crystallinity is composed of MgO, Mg2SiO4 and Mg2Si2O6.
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SBF immersion induces nucleation and precipitation of apatites on coating surface.
Co-reporter:Huijun Yu, Qing Dong, Jinhe Dou, Yaokun Pan, Chuanzhong Chen
Applied Surface Science 2016 Volume 388(Part A) pp:114-119
Publication Date(Web):1 December 2016
DOI:10.1016/j.apsusc.2016.03.028
Highlights
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Bioactive ceramic coatings formed on the ZK61 alloy surface.
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MAO coating with low crystallinity is composed of MgO, Mg2SiO4 and Mg2Si2O6.
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SBF immersion induces nucleation and precipitation of apatites on coating surface.
Co-reporter:H.C. Li, D.G. Wang, C.Z. Chen, F. Weng, H. Shi
Ceramics International 2016 Volume 42(Issue 1) pp:1439-1445
Publication Date(Web):January 2016
DOI:10.1016/j.ceramint.2015.09.088
Wollastonite (CaSiO3) ceramics with various Na2O contents (0, 5, 10, 15 and 20 mol%) were successfully prepared by sintering sol–gel derived precursors. The ceramics are composed of β-CaSiO3. With increasing Na2O content, Na2Ca2Si3O9, Na4Ca4Si6O18 and Na2CaSi3O8 are observed. The particle size distribution obeys the normal distribution. Na2O decreases the total pore volume of wollastonite powder, and increases the apparent porosity of wollastonite ceramic block. Na2O increases the bending strength of wollastonite, and the elastic moduli of all ceramics match that of cancellous bone of human body. The thermal expansion coefficients (TECs) of the ceramics are all close to that of titanium alloy (Ti6Al4V). The degradation rate is increased with increasing Na2O content. All samples show the ability of apatite induction in simulated body fluid (SBF) solution.
Co-reporter:J. Ma, C.Z. Wang, C.L. Ban, C.Z. Chen, H.M. Zhang
Vacuum 2016 Volume 125() pp:48-55
Publication Date(Web):March 2016
DOI:10.1016/j.vacuum.2015.12.005
•Mg-doped glass film was grown on porous Ti6Al4V by pulsed laser deposition.•Fine adhesion between the deposited film and the porous substrate was achieved.•The apatites were generated and grown on the prepared magnesium-doped glass film.•The surface-modified porous Ti6Al4V might be promising candidates as implant.Commercially pure Ti6Al4V (TC4) was pretreated by micro-arc oxidation (MAO) and then magnesium-containing bioactive glass thin film was successfully grown by pulsed laser deposition (PLD). After MAO and PLD treatments, the effects of MAO pretreatment and surface modification on the film bonding property and bioactivity were evaluated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and scratch tester. The results showed that the deposited film followed the surface relief of the porous MAO coating and strongly bonded to the substrate. And with increased immersion time in simulated body fluid (SBF), the lathlike and spherical apatites were generated and grown, indicating the surface-modified porous Ti6Al4V exhibit good bioactivity.
Co-reporter:H.C. Li, D.G. Wang, C.Z. Chen, F. Weng, H. Shi
Materials Letters 2015 Volume 157() pp:139-142
Publication Date(Web):15 October 2015
DOI:10.1016/j.matlet.2015.05.061
•The bioactive coatings on titanium alloy are prepared by laser cladding.•The cross-section morphologies are cellular crystal and cellular-dendrite structure.•The cross-section microstructure becomes coarse with increase of ZrO2 content.•The phase composition is related to the ZrO2 content.•The coating has the ability to form apatite in simulated body fluid.The bioactive coatings were prepared by laser cladding CaO–ZrO2–SiO2 system coatings on titanium alloy (Ti6Al4V). The cross-section morphologies of the coating are cellular crystal and cellular-dendrite structure. With the increase of ZrO2 content, the structure becomes coarse. The coating is mainly composed of CaTiO3, CaO, α-Ca2(SiO4), SiO2 and TiO2. When 5 mol% ZrO2 was added, CaZrO3 appears. With the increase of ZrO2 content, ZrO2 appears and CaO disappears. The surface of these coatings are coarse, accidented and partial porous. After soaking in simulated body fluid (SBF), apatite is formed on the coating surface.
Co-reporter:Fei Weng, Huijun Yu, Chuanzhong Chen, Jingjie Dai
Materials & Design (1980-2015) 2015 80() pp: 174-181
Publication Date(Web):5 September 2015
DOI:10.1016/j.matdes.2015.05.005
Co-reporter:Yaokun Pan, Siyu He, Diangang Wang, Danlan Huang, Tingting Zheng, Siqi Wang, Pan Dong, Chuanzhong Chen
Materials Science and Engineering: C 2015 Volume 47() pp:85-96
Publication Date(Web):1 February 2015
DOI:10.1016/j.msec.2014.11.048
•Ca and Zn are suitable alloying elements in the development of novel Mg implants.•Micropore and crack are two factors affecting the MAO coating corrosion behavior.•Dissolution and precipitation of apatites on MAO coating are reversible reactions.Calcium phosphate (CaP) ceramic coatings were fabricated on pure magnesium (Mg) and self-designed Mg–0.6Ca, Mg–0.55Ca–1.74Zn alloys by microarc oxidation (MAO). The coating formation, growth and biomineralization mechanisms were discussed. The coating degradability and bioactivity were evaluated by immersion tests in trishydroxymethyl–aminomethane hydrochloric acid (Tris–HCl) buffer and simulated body fluid (SBF) solutions, respectively. The coatings and corrosion products were characterized by scanning electron microscope (SEM), X-ray diffractometer (XRD), X-ray photoelectron spectrometer (XPS) and fourier transform infrared spectrometer (FT-IR). The electrochemical workstation was used to investigate the electrochemical corrosion behaviors of substrates and coatings. Results showed that Mg–0.55Ca–1.74Zn alloy exhibits the highest mechanical strength and electrochemical corrosion resistance among the three alloys. The MAO-coated Mg–0.55Ca–1.74Zn alloy has the potential to be served as a biodegradable implant.
Co-reporter:H.C. Li, D.G. Wang, C.Z. Chen, F. Weng
Colloids and Surfaces B: Biointerfaces 2015 Volume 127() pp:15-21
Publication Date(Web):1 March 2015
DOI:10.1016/j.colsurfb.2015.01.016
•The cross-section microstructure of cladding layer from top to bottom is different.•CeO2 and Y2O3 can refine the microstructure of the cladding surface layer.•The grain refinement effect is related to the kinds of additives and their content.•The coating has the ability to form calcium phosphate in simulated body fluid.•The addition of CeO2 or Y2O3 improves the degradability of laser cladding samples.To solve the lack of strength of bulk biomaterials for load-bearing applications and improve the bioactivity of titanium alloy (Ti–6Al–4V), CaO–SiO2 coatings on titanium alloy were fabricated by laser cladding technique. The effect of CeO2 and Y2O3 on microstructure and properties of laser cladding coating was analyzed. The cross-section microstructure of ceramic layer from top to bottom gradually changes from cellular–dendrite structure to compact cellular crystal. The addition of CeO2 or Y2O3 refines the microstructure of the ceramic layer in the upper and middle regions. The refining effect on the grain is related to the kinds of additives and their content. The coating is mainly composed of CaTiO3, CaO, α-Ca2(SiO4), SiO2 and TiO2. Y2O3 inhibits the formation of CaO. After soaking in simulated body fluid (SBF), the calcium phosphate layer is formed on the coating surface, indicating the coating has bioactivity. After soaking in Tris–HCl solution, the samples doped with CeO2 or Y2O3 present a lower weight loss, indicating the addition of CeO2 or Y2O3 improves the degradability of laser cladding sample.
Co-reporter:H.C. Li, D.G. Wang, C.Z. Chen
Materials Letters 2014 Volume 135() pp:237-240
Publication Date(Web):15 November 2014
DOI:10.1016/j.matlet.2014.07.177
•The main crystal phase of sample W-Mg in powder form and bulk form is different.•Na2O increases the degradation rate of wollastonite and MgO decreases this rate.•These ceramics are bioactive when soaked in simulated body fluid.•Na2O and MgO improve the bending strength of wollastonite.•The elastic moduli of ceramics are close to that of dense bone of human body.Wollastonite CaSiO3 (W-0) and CaSiO3 doped with Na2O (W-Na) or MgO (W-Mg) were synthesized by sintering sol–gel derived powders and compacts. The effects of Na2O and MgO on structure, in vitro bioactivity, degradability and mechanical properties of wollastonite were studied. The main crystal phases of these ceramic powders were β-CaSiO3. In addition, Na2Ca2Si3O9 appeared in sample W-Na and Ca3Mg(SiO4)2 appeared in W-Mg. For ceramic block W-Mg, CaMgSi2O6 appeared. After soaking in simulated body fluid (SBF) for 7 days, the apatite layer was formed on the surface of these ceramics. The addition of Na2O increased the degradation rate of wollastonite and MgO decreased the degradation rate. Na2O and MgO improved the bending strength of wollastonite. The elastic moduli of ceramics accorded with that of dense bone of human body.
Co-reporter:Y.K. Pan, D.G. Wang, C.Z. Chen
Materials Letters 2014 Volume 119() pp:127-130
Publication Date(Web):15 March 2014
DOI:10.1016/j.matlet.2013.12.103
•Negative voltage influences the ions transferring in the oxidation process.•Electrochemical corrosion resistance increases with increased negative voltage (0–100 V).•Negative voltage has an effect on the controllability of MAO coating degradability in SBF.Ceramic coatings were fabricated on ZK60 magnesium alloy by microarc oxidation (MAO) with different negative voltages. The coating degradability and bioactivity were evaluated by simulated body fluid (SBF) soaking test. A scanning electron microscope (SEM) and an X-ray diffractometer (XRD) were employed to characterize the coating morphology and phase composition. The electrochemical workstation was used to investigate the electrochemical corrosion properties of the samples. The results show that the coating growth mechanism can be influenced by the introduction and increase of negative voltage through affecting the direction and speed of ions transferring. With increase of negative voltage in the range of 0–100 V, the coating electrochemical corrosion property is improved, the coating degradation rate is reduced, and the combination property of coating corrosion resistance and apatites forming ability is enhanced.
Co-reporter:H.C. Li, D.G. Wang, J.H. Hu, C.Z. Chen
Materials Science and Engineering: C 2014 Volume 35() pp:171-178
Publication Date(Web):1 February 2014
DOI:10.1016/j.msec.2013.10.028
•The variations of additions account for the differences in internal structure.•The intensity ratio of SiO-NBO/SiO (s,sym) of G-NH4HF2 is higher than that of G-CaF2.•The bioactivity of G-NH4HF2 is better than that of G-CaF2.•The mechanical properties of G-NH4HF2 are lower than that of G-CaF2.•The glass–ceramics have good biocompatibility and are safe to serve as implants.Two series of Na2O–CaO–SiO2–P2O5 glass–ceramics doped with NH4HF2 (G-NH4HF2) or CaF2 (G-CaF2) have been prepared by sol–gel method. The glass–ceramic phase composition and morphology were characterized by X-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). The mechanical properties and thermal expansion coefficient were measured by a microhardness tester, an electronic tensile machine and a thermal expansion coefficient tester. The structure difference between these two glass–ceramics was investigated by Fourier transform infrared spectroscopy (FTIR), and the in vitro bioactivity of the glass–ceramics was determined by in vitro simulated body fluid (SBF) immersion test. The hemolysis test, in vitro cytotoxicity test, systemic toxicity test and the implanted experiment in animals were used to evaluate the biocompatibility of the glass–ceramics. The mechanical properties of sample G-NH4HF2 are lower than that of sample G-CaF2, and the bioactivity of sample G-NH4HF2 is better than that of sample G-CaF2. The thermal expansion coefficients of these two glass–ceramics are all closer to that of Ti6Al4V. After 7 days of SBF immersion, apatites were induced on glass–ceramic surface, indicating that the glass–ceramics have bioactivity. The hemolysis test, in vitro cytotoxicity test and systemic toxicity test demonstrate that the glass–ceramics do not cause hemolysis reaction, and have no toxicity to cell and living animal. The implanted experiment in animals shows that bone tissue can form a good osseointegration with the implant after implantation for two months, indicating that the glass–ceramics are safe to serve as implants.
Co-reporter:Jianing Li, Huijun Yu, Shuili Gong, Chuanzhong Chen, Fei Weng, Li Ding, Yaokun Pan, Feihu Shan
Surface and Coatings Technology 2014 Volume 247() pp:55-60
Publication Date(Web):25 May 2014
DOI:10.1016/j.surfcoat.2014.03.007
•Nanoscale particles, nanorods and amorphous phases were produced in such LC coating.•The amorphous/nanocrystalline interface owns a high bonding energy.•Amorphous/nanocrystalline interface may retard the growth of nanocrystals in a certain extent.•With the addition of Ce–Al–Ni amorphous alloy, the lots of micro/nanosize ASNPs were produced.An amorphous-nanocrystal reinforced composite coating was fabricated on Ti–6Al–4V titanium alloy by laser cladding (LC) of the Al3Ti–TiB2–(Ni-coated WC)–Al2O3–Y2O3 mixed powders. Test results indicate that the lots of the nanoscale particles (NP), nanorods and amorphous phases were produced in such coating. Amorphous/nanocrystalline interface owns a high bonding energy, which may retard the growth of nanocrystals in a certain extent. With Ce–Al–Ni amorphous addition, amorphous surrounded nanopolycrystals (ASNPs) were produced after the LC process. Although coarser microstructure was obtained with productions of ASNPs, the Ce–Al–Ni addition played an important amorphization effect on such LC coating, which was beneficial in increasing wear resistance of the LC coating.
Co-reporter:Y.K. Pan, C.Z. Chen, D.G. Wang, T.G. Zhao
Colloids and Surfaces B: Biointerfaces 2014 Volume 113() pp:421-428
Publication Date(Web):1 January 2014
DOI:10.1016/j.colsurfb.2013.09.044
Corrosion and biological properties of microarc oxidized calcium phosphate (CaP) coatings on Mg–Zn–Zr alloy were improved by optimizing negative power density parameters. Scanning electron microscope (SEM) and X-ray diffractometer (XRD) were employed to characterize the coating morphology and phase composition. The in vitro cytotoxicity and systemic toxicity tests were carried out to evaluate the coating biocompatibility. The degradability and bioactivity of the coatings were determined by in vitro simulated body fluid (SBF) immersion test. The coating microstructure, thickness and growth rate can be influenced by negative power density through changing direction of ions movements, rate of ions exchanges and affecting formation of plasma. The CaP coatings reduced the substrate degradation rate. Calcium phosphates, such as hydroxyapatite (Ca10(PO4)6(OH)2, HA) and calcium pyrophosphate (Ca2P2O7, CPP), etc., were induced after 30 days SBF immersion, indicating that the coatings have bioactivity. The CaP coatings have no toxicity to cell and living mice, indicating that the coatings are safe to serve as implants.
Co-reporter:Yaokun Pan, Chuanzhong Chen, Diangang Wang, Danlan Huang
Colloids and Surfaces B: Biointerfaces 2014 Volume 122() pp:746-751
Publication Date(Web):1 October 2014
DOI:10.1016/j.colsurfb.2014.08.012
•Si-containing coating was prepared on Mg–Zn–Ca alloy by microarc oxidation.•Electrochemical corrosion resistance of alloy was greatly enhanced by Si-coating.•Dissolution and precipitation behaviors of Si-coating in SBF was discussed.We prepared Si-containing and Si-free coatings on Mg–1.74Zn–0.55Ca alloy by micro-arc oxidation. The dissolution and precipitation behaviors of Si-containing coating in simulated body fluid (SBF) were discussed. Corrosion products were characterized by scanning electron microscope (SEM), X-ray diffractometer (XRD), fourier transform infrared spectrometer (FT-IR) and X-ray photoelectron spectrometer (XPS). Electrochemical workstation, inductively coupled plasma atomic emission spectrometer (ICP-AES), flame atomic absorption spectrophotometer (AAS) and pH meter were employed to detect variations of electrochemical parameter and ions concentration respectively. Results indicate that the fast formation of calcium phosphates is closely related to the SiOxn− groups, which induce the heterogeneous nucleation of amorphous hydroxyapatite (HA) by sorption of calcium and phosphate ions.
Co-reporter:H.C. Li, D.G. Wang, X.G. Meng, C.Z. Chen
Colloids and Surfaces B: Biointerfaces 2014 Volume 118() pp:226-233
Publication Date(Web):1 June 2014
DOI:10.1016/j.colsurfb.2014.03.055
•The crystallization and mechanical properties are greatly influenced by additives.•t-ZrO2 significantly improves the mechanical properties of glass-ceramics.•Nanometer apatite is formed on glass-ceramic surface in simulated body fluid.•The in vitro cytotoxicity test shows the glass-ceramic has no toxicity to cell.•The sedimentation mechanism and growth process of apatite on surface are discussed.A series of ZrO2 doped MgO–CaO–SiO2–P2O5–CaF2 bioactive glass-ceramics were obtained by sintering method. The crystallization behavior, phase composition, morphology and structure of glass-ceramics were characterized. The bending strength, elastic modulus, fracture toughness, micro-hardness and thermal expansion coefficient (TEC) of glass-ceramics were investigated. The in vitro bioactivity and cytotoxicity tests were used to evaluate the bioactivity and biocompatibility of glass-ceramics. The sedimentation mechanism and growth process of apatites on sample surface were discussed. The results showed that the mainly crystalline phases of glass-ceramics were Ca5(PO4)3F (fluorapatite) and β-CaSiO3 (β-wollastonite). m-ZrO2 (monoclinic zirconia) declined the crystallization temperatures of glasses. t-ZrO2 (tetragonal zirconia) increased the crystallization temperature of Ca5(PO4)3F and declined the crystallization temperature of β-CaSiO3. t-ZrO2 greatly increased the fracture toughness, bending strength and micro-hardness of glass-ceramics. The nanometer apatites were induced on the surface of glass-ceramic after soaking 28 days in SBF (simulated body fluid), indicating the glass-ceramic has good bioactivity. The in vitro cytotoxicity test demonstrated the glass-ceramic has no toxicity to cell.
Co-reporter:Fei Weng, Chuanzhong Chen, Huijun Yu
Materials & Design 2014 58() pp: 412-425
Publication Date(Web):
DOI:10.1016/j.matdes.2014.01.077
Co-reporter:H.C. Li, D.G. Wang, J.H. Hu, C.Z. Chen
Materials Letters 2013 Volume 106() pp:373-376
Publication Date(Web):1 September 2013
DOI:10.1016/j.matlet.2013.05.013
•The addition of K2O, MgO and B2O3 in glass can adjust glass network.•K2O and B2O3 decrease the integrity of glass network and promote crystallization.•K2O and B2O3 improve the bioactivity of the glass-ceramics.•MgO makes glass network become tighter and reduces glass-ceramic bioactivity.•The doping ions in glass remarkably improve the mechanical properties.Na2O–CaO–SiO2–P2O5 (45S5) system ceramics, in which CaO is partly replaced by K2O, MgO or B2O3, have been obtained by the sol–gel method. The crystallization, structure, mechanical properties and in vitro bioactivity of glass-ceramic were investigated. Results indicated that the doping ions in glass have remarkably improved the volume density, bending strength, fracture toughness and microhardness of the glass-ceramics. The addition of K2O and B2O3 decreased the integrity of glass network, promoted glass crystallization and crystallization did not inhibit glass bioactivity. The addition of MgO made the glass network much denser and decreased the ability of apatite induction.
Co-reporter:J. Ma, C.Z. Chen, D.G. Wang, C.Z. Wang, H.M. Zhang
Journal of Non-Crystalline Solids 2013 Volume 382() pp:5-10
Publication Date(Web):15 December 2013
DOI:10.1016/j.jnoncrysol.2013.09.024
•Magnesium-doped glass film was successfully grown on Ti6Al4V substrate by pulsed laser deposition (PLD).•Fine adhesion between the deposited film and the substrate was achieved.•The prepared magnesium-doped glass film promoted the formation of B-type HCA.•Magnesium-doped glass film might be promising candidates as implant materials.Magnesium-containing bioactive glass thin film was successfully grown on Ti6Al4V substrate by pulsed laser deposition (PLD). The obtained film was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). It is observed that the as-deposited film was dense and constituted with a large number of micron-sized and submicron-sized droplets. In vitro assays confirmed the apatite formation, and with increased immersion time, the Ca/P ratios of film surface gradually decreased to a stable value close to that of the stoichiometric value of hydroxyapatite (HA).
Co-reporter:Y.K. Pan, C.Z. Chen, D.G. Wang, Z.Q. Lin
Materials Chemistry and Physics 2013 Volume 141(2–3) pp:842-849
Publication Date(Web):16 September 2013
DOI:10.1016/j.matchemphys.2013.06.013
•Bioactive CaP coatings are successfully formed on ZK60 magnesium alloy.•CaP coatings consist of MgO, MgF2, CaO, CaF2 and Ca3(PO4)2.•Needle-like, spherical and columned calcium phosphates formed in SBF.•CaP coatings exhibit bioactivity and low corrosion rate.Calcium phosphate (CaP) coatings were prepared on ZK60 magnesium alloy by micro-arc oxidation (MAO) in electrolyte containing calcium acetate monohydrate (CH3COO)2Ca·H2O) and disodium hydrogen phosphate dodecahydrate (Na2HPO4·12H2O). Scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDX) and X-ray diffractometer (XRD) were employed to characterize the microstructure, elemental distribution and phase composition of the CaP coatings respectively. Simulated body fluid (SBF) immersion test was used to evaluate the coating degradability and bioactivity. After 30 days of SBF immersion, the CaP coatings effectively reduce the degradation rate. The surfaces of CaP coatings are covered by a new layer formed of numerous needle-like, spherical and columned calcium phosphates. SEM, EDX and XRD results suggest that these calcium phosphates are bioactive calcium phosphate phases such as hydroxyapatite (Ca10(PO4)6(OH)2, HA) and calcium pyrophosphates (Ca2P2O7, CPP). The formation of these calcium phosphates indicates that the CaP coatings have bioactivity.
Co-reporter:Y.K. Pan, C.Z. Chen, D.G. Wang, T.G. Zhao
Colloids and Surfaces B: Biointerfaces 2013 Volume 109() pp:1-9
Publication Date(Web):1 September 2013
DOI:10.1016/j.colsurfb.2013.03.026
•Bioactive CaP coatings are successfully formed on ZK60 magnesium alloy.•Different phosphates do not change the phases of CaP coatings.•Fluorides released during the SBF immersion do not cause observed adverse effect.•CaP coatings E3 show lower degradation rate, better bioactivity and biocompatibility.Calcium phosphate (CaP) coatings were prepared on Mg–Zn–Zr magnesium alloy by micro-arc oxidation (MAO) in electrolyte containing calcium acetate monohydrate (CH3COO)2Ca·H2O) and different phosphates (i.e. disodium hydrogen phosphate dodecahydrate (Na2HPO4·12H2O), sodium phosphate (Na3PO4·H2O) and sodium hexametaphosphate((NaPO3)6)). Scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDS) and X-ray diffractometer (XRD) were employed to characterize the microstructure, elemental distribution and phase composition of the CaP coatings. Simulated body fluid (SBF) immersion test was used to evaluate the coating bioactivity and degradability. Systemic toxicity test was used to evaluate the coating biocompatibility. Fluoride ion selective electrode (ISE) was used to measure F− ions concentration during 30 days SBF immersion. The CaP coatings effectively reduced the corrosion rate and the surfaces of CaP coatings were covered by a new layer formed of numerous needle-like and scale-like apatites. The formation of these calcium phosphate apatites indicates that the coatings have excellent bioactivity. The coatings formed in (NaPO3)6-containging electrolyte exhibit thicker thickness, higher adhesive strength, slower degradation rate, better apatite-inducing ability and biocompatibility.
Co-reporter:H. C. Li;D. G. Wang;J. H. Hu;C. Z. Chen
Journal of Sol-Gel Science and Technology 2013 Volume 67( Issue 1) pp:56-65
Publication Date(Web):2013 July
DOI:10.1007/s10971-013-3050-5
The partial substitution of CaF2 for CaO in the Na2O–CaO–SiO2–P2O5 system was conducted by the sol–gel method and a comparison of the glass–ceramic properties was reported. Based on thermogravimetric and differential thermal analysis, the gels were sintered with a suitable heat treatment procedure. The glass–ceramic properties were characterized by X-ray diffraction, fourier-transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectrometer and so on, and the bioactivity of the glass–ceramic was evaluated by in vitro assays in simulated body fluid. Results indicate that with the partial substitution of CaF2 for CaO in glass composition, the volume density, apparent porosity, bending strength and microhardness of the glass–ceramics have been significantly improved. Furthermore, CaF2 promotes glass crystallization which does not inhibit the glass–ceramic bioactivity.
Co-reporter:Jianing Li, Huijun Yu, Chuanzhong Chen, and Shuili Gong
The Journal of Physical Chemistry C 2013 Volume 117(Issue 9) pp:4568-4573
Publication Date(Web):February 7, 2013
DOI:10.1021/jp311138f
Amorphous surrounded nano polycrystals (ASNP) are found in this study. An amorphous nanocrystal-reinforced coating was fabricated on an important aeronautical material Ti-6Al-4V titanium alloy by laser cladding of the Al3Ti-TiB2-SiC-Cu-Y2O3 mixed powders. Transmission electron microscope and scanning electron microscope test results indicated that with Cu addition, the TiCu2Al nano polycrystals were produced in the matrix of laser clad coating, which grew along (200), (220), (222), and (400) planes; high resolution transmission electron microscope image indicated that with glass addition, the particles grew up, leading to the formation of a micronano structure. Moreover, Cu addition led the agglomeration of ASNP to decompose then distributed uniformly in the coating matrix. This research provided essential theoretical and experimental basis to promote the application of laser cladding technique in the modern aviation industry.
Co-reporter:Y.K. Pan, C.Z. Chen, D.G. Wang, X. Yu, Z.Q. Lin
Ceramics International 2012 Volume 38(Issue 7) pp:5527-5533
Publication Date(Web):September 2012
DOI:10.1016/j.ceramint.2012.03.068
Abstract
Ceramic coatings were fabricated on ZK60 magnesium alloy substrate by microarc oxidation (MAO) in Na2SiO3–KOH base electrolyte with four kinds of additives (i.e. KF, NH4HF2, C3H8O3 and H2O2). The effects of these additives on microstructure and property of coatings were investigated. The surface morphology, phase composition and corrosion resistance of the ceramic coatings were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and simulation body fluid (SBF) immersion test respectively. It is found that different additives can change the spark discharge phenomenon during microarc oxidation. It is proved that both potassium fluoride (KF) and ammonium bifluoride (NH4HF2) promote discharge and accelerate reaction while the introduce of glycerol (C3H8O3) leads to the refining of sparks and reduction of thermal effects. Results also demonstrate that the introduce of hydrogen peroxide (H2O2) contributes to the increase of coating surface roughness and enlargement of surface micropore size. XRD results indicate that the ceramic coatings are mainly composed of Mg2SiO4, MgSiO3 and SiO2. The introduce of H2O2 hinders the reaction between SiO2 and MgO and creates favorable conditions for the formation of the MgO phase. The ceramic coatings formed in base electrolyte containing 7 g/L NH4HF2 and 5 mL/L C3H8O3 exhibit the highest corrosion resistance.
Co-reporter:J. Ma, C.Z. Chen, D.G. Wang, X. Shao, C.Z. Wang, H.M. Zhang
Ceramics International 2012 Volume 38(Issue 8) pp:6677-6684
Publication Date(Web):December 2012
DOI:10.1016/j.ceramint.2012.05.056
Abstract
CaO–MgO–SiO2–P2O5 glass ceramics were successfully prepared by sintering the sol–gel-derived powders. The effects of MgO addition on the samples crystallization and structure were investigated by means of differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, samples degradation and in vitro bioactivity assays were also evaluated. With more MgO addition, the glass ceramics crystallization kinetics under non-isothermal conditions changed from bulk crystallization to surface crystallization, and new crystal phases of Ca2MgSi2O7 and SiO2 were induced. In addition, it is observed that with increasing MgO concentration, the glass ceramics degradability gradually decreased and the formation of apatite was delayed.
Co-reporter:Jianing Li, Chuanzhong Chen, Qingshan He
Materials Chemistry and Physics 2012 Volume 133(2–3) pp:741-745
Publication Date(Web):16 April 2012
DOI:10.1016/j.matchemphys.2012.01.082
The TiC/TiB/TiN reinforced composite coating was prepared by laser cladding of the Fe/Al + B4C/SiC pre-placed powders on Ti–6Al–4V alloy in the nitrogen protective atmosphere. Nevertheless, the pores and micro-crack were present in this coating. Through the experiment, it was found that Cu can be used to improve the microstructure and wear resistance of this composite coating, and Ti3CuN/Ti2Cu/CuAl were produced. Due to the action of Cu, the crystals had enough time to grow up, and the wear volume loss of the composite coating was approximately 7–8 times less than that of the Ti–6Al–4V substrate.Graphical abstractHighlights► Fe/Al + B4C/SiC laser-cladded coating can improve the surface performance of the titanium alloys. ► Cu is able to improve the microstructures and wear resistance of this coating. ► This Cu reinforced coating exhibited a compact microstructure free of the pores and micro-crack. ► With addition of Cu, TiB2 crystals have enough time to grow up. ► The grew TiB2 crystals are beneficial in improving the performance of this coating.
Co-reporter:Y. K. Pan;C. Z. Chen;D. G. Wang;X. Yu
Journal of Biomedical Materials Research Part B: Applied Biomaterials 2012 Volume 100B( Issue 6) pp:1574-1586
Publication Date(Web):
DOI:10.1002/jbm.b.32726
Abstract
Ceramic coatings were prepared on ZK60 magnesium alloy in electrolyte with different concentration ratio of calcium and phosphorus (Ca/P) by micro-arc oxidation (MAO) technique at constant voltage. The microstructure, phase composition, elemental distribution, corrosion resistance, and adhesion of the coatings were investigated by scanning electron microscope (SEM), X-ray diffractometer (XRD), energy-dispersive X-ray spectrometry (EDS), electrochemical workstation, and scratch spectrometer, respectively. The coating biocompatibility was evaluated by in vitro cytotoxicity tests and systemic toxicity tests, and the bioactivity and degradability were evaluated by simulation body fluid (SBF) immersion tests. SEM shows that pores with different shapes distribute all over the coating surface. The adhesion and thickness of the coatings increases with increasing Ca/P ratio of electrolyte. The in vitro cytotoxicity tests and systemic toxicity texts demonstrate that the coatings have no toxicity to cell and living animal, which show that the coatings have excellent biocompatibility. XRD analysis shows that bioactive calciumphosphate (CaP) phases such as hydroxyapatite (HA, Ca10(PO4)6(OH)2) and calcium pyrophosphate (CPP, Ca2P2O7) are induced in the immersed coatings, indicating that the MAO coatings have excellent bioactivity. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 100B: 1574–1586, 2012.
Co-reporter:LI JIANING;CHEN CHUANZHONG;ZHANG CUIFANG
Bulletin of Materials Science 2012 Volume 35( Issue 3) pp:399-404
Publication Date(Web):2012 June
DOI:10.1007/s12034-012-0307-5
TiC/TiN+TiCN reinforced composite coatings were fabricated on Ti–6Al–4V alloy by laser cladding, which improved surface performance of the substrate. Nano-CeO2 was able to suppress crystallization and growth of the crystals in the laser-cladded coating to a certain extent. With the addition of proper content of nano-CeO2, this coating exhibited fine microstructure. In this study, the Al3Ti+TiC/TiN+nano-CeO2 laser-cladded coatings were studied by means of X-ray diffraction and scanning electron microscope. The X-ray diffraction results indicated that the Al3Ti+TiC/TiN+nano-CeO2 laser-cladded coating consisted of Ti3Al, TiC, TiN, Ti2Al20Ce, TiC0·3N0·7, Ce(CN)3 and CeO2, this phase constituent was beneficial to increase the microhardness and wear resistance of Ti–6Al–6V alloy.
Co-reporter:Jianing Li, Chuanzhong Chen, Diangang Wang, Wei Li
Composites Part B: Engineering 2012 Volume 43(Issue 3) pp:896-901
Publication Date(Web):April 2012
DOI:10.1016/j.compositesb.2011.10.003
In this study, the influence of YPSZ/CeO2 on the surface performance of the laser-cladded composites was firstly researched. Laser cladding of the Fe3Al/Co42B + YPSZ/CeO2 pre-placed powders on Ti–6Al–4V alloy can form the composite coating, which increased the wear resistance of the substrate. With addition of 20 wt.%TiC, the longevity of the molten pool decreased, leading to the decreasing of the growth time of the precipitates and the content of CoTi, TiNi, AlNi, Ti3Al and TiB phases. The addition of 20 wt.%TiC did not improve the tribological properties of the Fe3Al/Co42B + YPSZ/CeO2 laser-cladded composite coating.
Co-reporter:D.G. Wang, C.Z. Chen, J. Ma, T. He
Applied Surface Science 2011 Volume 257(Issue 7) pp:2592-2598
Publication Date(Web):15 January 2011
DOI:10.1016/j.apsusc.2010.10.028
Abstract
Bioactive hydroxyapatite films were fabricated on titanium alloy by a sol–gel method. The samples were firstly precoated at a low drying temperature for many times and then calcined at a relative high temperature. The phase constitution, microstructure and composition analysis were studied by X-ray diffraction (XRD), electronic probe microanalysis (EPMA), and the microstructure evolution was explained by some schematic illustrations. When the samples were precoated only once, hexagonal structure is always observed. After the samples were precoated many times, the hexagonal structure can be preserved only when the drying temperature is 500 °C or above. When the drying temperature is below 500 °C, the dried layer easily redissolved into the next coated sol because of the existence of some water-soluble ions such as NO3−, consequently the hexagonal structure disappeared and a coarse surface with some small pores formed. High calcining temperature can accelerate the atomic diffusion which may integrate the adjacent grains, but excessively high temperature such as 900 °C or above would make the whole film be incinerated completely.
Co-reporter:Jianing Li, Chuanzhong Chen, Zhaoqing Lin, Tiziano Squartini
Journal of Alloys and Compounds 2011 Volume 509(Issue 14) pp:4882-4886
Publication Date(Web):7 April 2011
DOI:10.1016/j.jallcom.2011.01.199
Laser cladding of the Fe3Al + TiB2/Al2O3 pre-placed alloy powder on Ti–6Al–4V alloy can form the Ti3Al/Fe3Al + TiB2/Al2O3 ceramic layer, which can greatly increase wear resistance of titanium alloy. In this study, the Ti3Al/Fe3Al + TiB2/Al2O3 ceramic layer has been researched by means of electron probe, X-ray diffraction, scanning electron microscope and micro-analyzer. In cladding process, Al2O3 can react with TiB2 leading to formation of amount of Ti3Al and B. This principle can be used to improve the Fe3Al + TiB2 laser cladded coating, it was found that with addition of Al2O3, the microstructure performance and micro-hardness of the coating was obviously improved due to the action of the Al–Ti–B system and hard phases.Research highlights► In this study, Fe3Al has been chosen as cladding powder due to its excellent properties of wear resistance and high strength, etc. ► Laser cladding of Fe3Al + TiB2/Al2O3 pre-placed alloy powder on Ti-6Al-4V alloy substrate can form the Ti3Al/Fe3Al + TiB2/Al2O3 ceramic layer, which can increase wear resistance of substrate. ► In cladding process, Al2O3 can react with TiB2 leading to formation of Ti3Al and B. ► This principle can be used to improve the Fe3Al + TiB2 laser-cladded coating.
Co-reporter:J. Ma, C.Z. Chen, D.G. Wang, J.H. Hu
Ceramics International 2011 Volume 37(Issue 5) pp:1637-1644
Publication Date(Web):July 2011
DOI:10.1016/j.ceramint.2011.01.043
Abstract
Bioactive glass and glass-ceramics in the system CaO–MgO–SiO2–P2O5 have been prepared by the sol–gel and high temperature sintering techniques. The obtained samples were characterized by thermogravimetric and differential thermal analysis (TG/DTA), N2-adsorption measurement, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). In vitro bioactivity tests were also conducted in simulated body fluid (SBF). The studies of crystallization kinetics under non-isothermal conditions showed the activation energy for crystallization to be 381 kJ/mol and the crystallization mechanism gradually changed from three-dimension growth to two-dimension crystallization with the increase of heating rate. Sintering temperature had great influence on the samples texture and structure. In addition, the apatite-formation on glass and glass-ceramics was confirmed by in vitro tests, and crystallization decreased the samples bioactivity.
Co-reporter:J. Ma, C.Z. Chen, D.G. Wang, J.H. Hu
Materials Letters 2011 Volume 65(Issue 1) pp:130-133
Publication Date(Web):15 January 2011
DOI:10.1016/j.matlet.2010.09.040
CaO–MgO–P2O5–SiO2 system ceramics with various magnesia contents (0, 5, 10 and 20 mol%) were successfully prepared by sintering the sol–gel-derived powder compacts. The ceramic degradation was evaluated through the weight loss in the tris-(hydroxymethyl)-aminomethane and hydrochloric acid (Tris–HCl) buffer solution, and their ability to form apatite was determined by soaking in simulated body fluid (SBF). Results indicated that the ceramics structure was greatly influenced by magnesia contents. New crystal phases of Ca2MgSi2O7 and SiO2 were formed when magnesia was added and with an increase of magnesia concentration the phase of Ca2MgSi2O7 increased with a simultaneous decline of β-CaSiO3. In addition, studies showed that magnesia played an important role in affecting the degradability and apatite forming ability of CaO–MgO–P2O5–SiO2 system ceramics. It is observed that with increasing magnesia concentration, the ceramic degradability gradually decreased and the formation of apatite on samples was delayed.
Co-reporter:J. Ma, C.Z. Chen, D.G. Wang, X.G. Meng, J.Z. Shi
Ceramics International 2010 Volume 36(Issue 6) pp:1911-1916
Publication Date(Web):August 2010
DOI:10.1016/j.ceramint.2010.03.017
Abstract
A sol–gel method was utilized to synthesize the gel with the composition of 58 mol% SiO2–38 mol% CaO–4 mol% P2O5. The thermal properties were studied using thermogravimetric and differential thermal analysis (TG/DTA). Then the gels were sintered at 700, 900, 1000 and 1200 °C. The structure features were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), in addition in vitro assays were carried out in simulated body fluid (SBF). The results revealed that at sintering temperature above 900 °C, crystallization occurred and glass-ceramics with pseudowollastonite and wollastonite were formed. Furthermore with the increase of sintering temperature, the amount of pseudowollastonite decreased while that of wollastonite increased. In vitro tests indicated that the crystallization did not inhibit the samples bioactivity. After soaking in SBF, the formation of apatite was confirmed on glass and glass-ceramics surface, and the bioactivity of the glass-ceramics was based on the formed pseudowollastonite and wollastonite.
Co-reporter:J. Ma, C.Z. Chen, D.G. Wang, J.Z. Shi
Materials Science and Engineering: C 2010 30(6) pp: 886-890
Publication Date(Web):
DOI:10.1016/j.msec.2010.04.005
Co-reporter:J. Ma;C. Z. Chen;D. G. Wang;X. G. Meng
Journal of Sol-Gel Science and Technology 2010 Volume 54( Issue 1) pp:69-76
Publication Date(Web):2010 April
DOI:10.1007/s10971-010-2159-z
Two glasses of the CaO-MgO-P2O5-SiO2 system with different MgO contents (0 and 10 mol%, respectively) have been synthesized by sol–gel method. The degradation of glass samples was evaluated through the weight loss in the tris-(hydroxymethyl)-aminomethane and hydrochloric acid (Tris–HCl) buffer solution, and the in vitro bioactivity was assessed by determining the changes in surface morphology and composition after soaking in a simulated body fluid. Formation of the apatite-like layer on glasses surface was studied by means of X-ray diffraction, Fourier-transform infrared, scanning electron microscopy. Results indicate that, with the partial substitution of MgO for CaO in glass composition, the glass degradation decrease and the formation of apatite-like layer is delayed. Furthermore, it is observed that the glass bioactivity is relative to its dissolution, and the effects of MgO on glass degradability and bioactivity may be attributed to the influence of ionic field strength and distinct bonding configuration of glass.
Co-reporter:J. Ma, C.Z. Chen, D.G. Wang, Y. Jiao, J.Z. Shi
Colloids and Surfaces B: Biointerfaces 2010 Volume 81(Issue 1) pp:87-95
Publication Date(Web):1 November 2010
DOI:10.1016/j.colsurfb.2010.06.022
Mesoporous 58SiO2–(38 − x)CaO–xMgO–4P2O5 glasses (where x = 0, 5, 10 and 20 mol%) have been prepared by the sol–gel synthesis route. The effects of the substitution of MgO for CaO on glass degradation and bioactivity were studied in tris-(hydroxymethyl)-aminomethane and hydrochloric acid buffer solution (Tris–HCl) and simulated body fluid (SBF), respectively. It is observed that the synthesized glasses with various MgO contents possess the similar textural properties. The studies of in vitro degradability and bioactivity show that the rate of glass degradation gradually decreases with the increase of MgO and the formation of apatite layer on glass surface is retarded. The influences of the composition upon glass properties are explained in terms of their internal structures.
Co-reporter:Quanhe Bao, Chuanzhong Chen, Diangang Wang and Junming Liu
Crystal Growth & Design 2008 Volume 8(Issue 1) pp:219
Publication Date(Web):November 30, 2007
DOI:10.1021/cg070151e
Hydroxyaptite (HA) films were prepared by pulsed laser deposition from two kinds of targets using a KrF excimer laser at a substrate temperature of 575 °C. The characterization of films was studied by an electron probe microanalyzer, scanning electron microscopy, atomic force microscopy, glancing angle X-ray diffraction, and Fourier transform infrared spectroscopy. In vitro tests were performed to study the biocompatibility of the films. The results showed that the films were crystalline and there was a substitution of CO32− for PO43−. In vitro tests showed that with increased immersion time, the crystallinity of films became low, and the Ca/P ratio of films decreased first and then stayed at a stable value which is lower than that of the theoretical value of hydroxyapatite. The bands of new precipitated bonelike apatite were the same as with the original HA films, which indicated that the films had a good biocompatibility. The sintered temperature of the target had a small effect on the microstructure, while the coarse film could increase the bonelike apatite formation rate, which indicated that the bioactivity of coarse film was better.
Co-reporter:D.G. Wang, C.Z. Chen, J. Ma, T.H. Liu
Applied Surface Science 2008 Volume 255(Issue 5) pp:1637-1645
Publication Date(Web):30 December 2008
DOI:10.1016/j.apsusc.2008.09.053
Abstract
Because of its excellent ferroelectric properties including piezoelectricity, thermoelectricity and photoelectricity, the lead-based titanate ferroelectric thin films have been widely used in the high-tech fields such as microelectronics, optoelectronics, integrated optics and microelectro-mechanical system. As a significant technique in preparing thin films, the sol–gel method has achieved great success in preparing the lead-based titanate ferroelectric thin films. In this paper, the sol–gel fundamental, deposition process and the advantage of sol–gel technique in fabricating ferroelectric thin films were concluded. The materials selection, ferroelectric properties, application fields of lead titanate, lead calcium titanate, lead zirconate titanate, some other lead-based titanate thin films by sol–gel were reviewed, and the influencing factors on the properties of ferroelectric films were discussed.
Co-reporter:Diangang Wang;Ting He
Journal of Materials Science: Materials in Medicine 2008 Volume 19( Issue 6) pp:2281-2286
Publication Date(Web):2008 June
DOI:10.1007/s10856-007-3338-5
Using trimethyl phosphate and calcium nitrate tetrahydrate as the calcium and phosphorus precursors, respectively, HA films were prepared layer by layer by a sol–gel method. The phase constitution, microstructure and calcium/phosphorus (Ca/P) molar ratio of the sol–gel films were studied by X-ray diffraction (XRD) and electronic probe microanalysis (EPMA). The results show that the sol–gel films have high crystallinity and are composed of HA and CaO phases, and the Ca/P ratio is slightly higher than the theoretical value in HA because of the loss of phosphorous element. Two typical cauliflower-like and lamellar structures were observed in the films. Cauliflower-like structure, which increases the biological reactivity of the implant surface towards natural bone, formed mainly at low drying temperature and high calcining temperature, while the lamellar structure formed when the drying temperature is high (500 °C or above).
Co-reporter:J. Z. Shi;C. Z. Chen;H. J. Yu;S. J. Zhang
Bulletin of Materials Science 2008 Volume 31( Issue 6) pp:
Publication Date(Web):2008 November
DOI:10.1007/s12034-008-0140-z
Radio frequency (RF) magnetron sputtering is a versatile deposition technique that can produce thin, uniform, dense calcium phosphate coatings. In this paper, principle and character of magnetron sputtering is introduced, and development of the hydroxyapatite and its composite coatings application is reviewed. In addition, influence of heat treatment on magnetron sputtered coatings is discussed. The heat treated coatings have been shown to exhibit bioactive behaviour both in vivo and in vitro. At last, the future application of the bioactive ceramic coating deposited by magnetron sputtering is mentioned.
Co-reporter:Diangang Wang, Chuanzhong Chen, Jie Ma, Tingquan Lei
Applied Surface Science 2007 Volume 253(Issue 8) pp:4016-4020
Publication Date(Web):15 February 2007
DOI:10.1016/j.apsusc.2006.08.036
Abstract
The yttric calcium phosphate (CaP) coatings were in situ prepared on pure titanium substrate by laser cladding. The morphologies and phases constitution of CaP coatings were studied by electron probe microanalysis, X-ray diffraction and so on. The bonding state between the coating and the substrate is fine metallurgical combination, and the addition of yttria can fine the structure and increase the tensile strength of the coatings. The X-ray result shows that the coating is composed of the phases of HA, α-Ca2P2O7, β-Ca2P2O7 and CaTiO3.
Co-reporter:Diangang Wang, Chuanzhong Chen, Xiuna Liu, Tingquan Lei
Colloids and Surfaces B: Biointerfaces 2007 Volume 57(Issue 2) pp:237-242
Publication Date(Web):15 June 2007
DOI:10.1016/j.colsurfb.2007.02.003
Bioactive hydroxyapatite (HA) films were fabricated by a sol–gel method and triethylphosphate and calcium nitrate were used as the phosphorus and calcium precursors, respectively. The effects of the heat treatment temperature, pH level and substrate materials on the phases and microstructures of HA films were studied by X-ray diffraction (XRD), scanning electronic microscopy (SEM) and electronic probe microanalysis (EPMA) and so on. The results show that all the sol–gel films are composed of the phases of HA, CaO, TiO2 and CaTiO3. With increasing the calcining temperature, the crystallinity of the films increases, the structure becomes more compact and changes from granular and lamellar to cellular structure, and the Ca/P ratio increases slightly because of the loss of P in the films. The addition of ammonia (adjusting the pH level to be about 7.5) can increase the HA content in the films, and the difference of substrate materials only has a little influence on the microstructure of the sol–gel films.
Co-reporter:Quanhe Bao, Chuanzhong Chen, Diangang Wang, Tingquan Lei, Junming Liu
Materials Science and Engineering: A 2006 Volume 429(1–2) pp:25-29
Publication Date(Web):15 August 2006
DOI:10.1016/j.msea.2006.04.003
This study was aimed at the pulsed laser deposition of hydroxyapatite (HA) thin films onto Ti substrate using KrF excimer laser. The deposition was carried out under an atmosphere of Ar at 45 Pa. The films structures have been analyzed by EPMA, TEM, XRD and Raman spectroscopy. It can be observed that the films are mainly composed of droplet-like particles which size of 0.2–2 μm. The results of XRD, TEM and Raman spectroscopy show that the films are amorphous. The ratio of Ca/P is 1.97, which is higher than that of HA. After heat treatment the XRD pattern show that the films were consist of HA and TiO2. The ratio of Ca/P is 1.82, which is close to that of crystalline HA.
Co-reporter:Quanhe Bao, Chuanzhong Chen, Diangang Wang, Qianmao Ji, Tingquan Lei
Applied Surface Science 2005 Volume 252(Issue 5) pp:1538-1544
Publication Date(Web):15 December 2005
DOI:10.1016/j.apsusc.2005.02.127
Abstract
Pulsed laser deposition (PLD) is a conceptually and experimentally simple yet highly versatile tool for thin films and multi-layer film research. The mechanisms, advantages and disadvantages of pulsed laser deposition were reviewed. The process and some methods to resolve the drawbacks of PLD were discussed. Pulsed laser deposition of hydroxyapatite thin films was reviewed. Simple adjustment of PLD parameters can deposit hydroxyapatite in situ in crystalline form, amorphous films or HA with other calcium phosphate phases. Compared with plasma sprayed HA coatings the pulsed laser deposition HA thin films have higher coating/substrate adhesion and have minor undesirable phases under optimal conditions. Finally, we suggested some new researches should be done.
Co-reporter:Jianli Liu, Huijun Yu, Chuanzhong Chen, Fei Weng, Jingjie Dai
Optics and Lasers in Engineering (June 2017) Volume 93() pp:
Publication Date(Web):June 2017
DOI:10.1016/j.optlaseng.2017.02.007
•Laser cladding material systems on magnesium alloys are reviewed entirely.•Novel devices used for laser cladding are summarized.•The existing problems and the corresponding solutions are discussed.•Potential development tendency is forecasted based on the latest research progress.Magnesium alloys are one of the most promising lightweight structural materials. However, the poor corrosion and wear resistance restrain their further application. As a kind of surface modification technique, laser cladding treatment is superior to others owing to its unique characteristics such as high efficiency and the metallurgical bonding between the coatings and substrates. In this paper, the laser cladding process and the effects of processing parameters, including laser power, scanning velocity, beam focal position, feeding ways of the material etc., are discussed in detail. The material systems preplaced on magnesium alloys are summarized. Except for the traditional metallic materials, novel ternary alloys, amorphous alloys and high entropy alloys (HEAs) are widely used and apparent advantages are exhibited. In terms of the problems existing in the laser cladding process of magnesium alloys, some potential solutions and the development tendency are reviewed.
Co-reporter:Fei Weng, Huijun Yu, Jianli Liu, Chuanzhong Chen, Jingjie Dai, Zhihuan Zhao
Optics & Laser Technology (1 July 2017) Volume 92() pp:
Publication Date(Web):1 July 2017
DOI:10.1016/j.optlastec.2017.01.014
•Composite coatings reinforced with multiple phases were fabricated.•The microhardness of the coatings increased with more SiC addition.•Too much SiC addition (20 wt%) led to cracks in the cladding coating.Ti5Si3/TiC reinforced Co-based composite coatings were fabricated on Ti-6Al-4V titanium alloy by laser cladding with Co42 and SiC mixture. Microstructure and wear property of the cladding coatings with different content of SiC were investigated. During the cladding process, the original SiC dissolved and reacted with Ti forming Ti5Si3 and TiC. The complex in situ formed phases were found beneficial to the improvement of the coating property. Results indicated that the microhardness of the composite coatings was enhanced to over 3 times the substrate. The wear resistance of the coatings also showed distinct improvement (18.4–57.4 times). More SiC gave rise to better wear resistance within certain limits. However, too much SiC (20 wt%) was not good for the further improvement of the wear property.
Co-reporter:D.G. Wang, C.Z. Chen, Q.S. Ma, Q.P. Jin, H.C. Li
Applied Surface Science (1 April 2013) Volume 270() pp:
Publication Date(Web):1 April 2013
DOI:10.1016/j.apsusc.2013.01.117
HA/45S5 composite films were deposited by pulsed laser, the crystalline phases, microstructure and bonding configurations of the films were studied by XRD, SEM and FTIR respectively, and the film-to-substrate adhesion was investigated by micro-scratch testing. In addition, the in vitro and in vivo assays were carried out.The results showed that the crystallinity and the adhesive strength of the films increased with the increase of the substrate temperature. The film deposited with the substrate temperature of 200 °C is amorphous, while crystalline HA and β-TCP were detected in the film deposited at 600 °C. The in vitro test indicates that the amorphous film has faster dissolution rate and reprecipitation rate, which implies that this film has better bioactivity than the crystalline film. However, the in vivo test suggested that the 600 °C film was more suitable to serve as clinical application than the 200 °C film, because new bone tissue grew better onto the 600 °C film surface than onto the 200 °C film surface when they were implanted in the rabbit shin bones.Highlights► High substrate temperature improves the properties of the HA/BG composite PLD film. ► Comparative study of the bioactivity of the amorphous film and crystal film. ► The amorphous film has faster dissolution rate and reprecipitation rate in SBF solution than crystal film. ► The 600 °C film is more suitable to serve as clinical application than the 200 °C film.
Co-reporter:Jinhe Dou, Yang Chen, Yiming Chi, Huancai Li, Guochao Gu and Chuanzhong Chen
Physical Chemistry Chemical Physics 2017 - vol. 19(Issue 23) pp:NaN15119-15119
Publication Date(Web):2017/05/19
DOI:10.1039/C7CP02672B
Magnesium alloys are the most promising implant materials due to their excellent biodegradability. However, their high degradation rate limits their practical application. In this study, we produced a calcium–phosphate (Ca–P) coating and a calcium–phosphate–silicon (Ca–P–Si) coating via one-step and two-step micro-arc oxidation processes, respectively. The microstructure and chemical composition of the MAO coatings were characterized using SEM, XRD and EDS. The degradation behaviors of the MAO coatings and the substrate were investigated using electrochemical techniques and immersion tests in simulated body fluid (SBF). The results show that the silicate was successfully incorporated into the Ca–P coating in the second MAO step, and this also increased the thickness of the coating. The Ca–P–Si coatings remarkably reduced the corrosion rate of the Mg alloy and Ca–P coating during 18 days of immersion in SBF. In addition, the bone-like apatite layer on the sample surface demonstrated the good biomineralization ability of the Ca–P–Si coating. Potentiodynamic polarization results showed that the MAO coating could clearly enhance the corrosion resistance of the Mg alloy. Moreover, we propose the growth mechanism of the MAO coating in the second step.
