Investigation for the Electrophoretic Deposition of Hydroxyapatite and its Composite Coating on Titanium

Ca10(PO4)6(OH)2（羟基磷灰石，HA）是人骨等硬组织的主要无机成分，具备高的生物活性及骨传导性能，被广泛用作为生物医学植入材料。然而，纯HA陶瓷材料的力学性能较差，如脆性大，限制了它在生物医学领域的应用。为此人们致力于发展各种HA涂层或复合材料。在医用金属上涂覆HA涂层是目前复合生物医学材料领域的研究热点之一。已发展了多种在医用金属钛表面涂覆HA生物活性涂层的方法，其中，电泳沉积法，由于其工艺灵活性，低成本以及许多其它的优点，近年来受到了广泛的关注。本论文针对钛表面电泳沉积HA涂层材料面临的涂层烧结及涂层－基体界面结合的问题，作了如下研究工作。 一、在以无水乙醇作为分散溶剂的分散...Ca10(PO4)6(OH)2 (Hydroxyapatite, HA), a major inorganic component of human bone and other hard tissues, has been used extensively for biomedical implant applications and bone regeneration due to its bioactive and osteoconductive properties. However, the poor mechanical properties of pure HA ceramic, such as its brittleness, have limited its clinical applications. For this reason, a great deal of r...学位：工学硕士院系专业：化学化工学院材料科学与工程系_材料学学号：20043602

EFFECTS OF SUSPENSION POWDER CONTENT ON THE ELECTROPHORETIC DEPOSITION OF HYDROXYAPATITE COATINGS

从不同羟基磷灰石(hydroxyapatite,HA)粉体含量的悬浮液中,在钛表面电泳沉积HA涂层。采用扫描电镜、X射线衍射表征涂层的微观形貌及物相组成,通过黏结-拉伸实验测定涂层与基底的结合强度。结果表明:提高悬浮液的HA粉体含量,有助于提高电泳沉积HA涂层的致密性,改善其烧结性能,提高烧结致密化程度;HA涂层致密性的提高,有效地抑制了钛基底表面氧化反应,改善了涂层与基底的界面结合状态,使HA涂层与钛基底的结合强度从悬浮液HA粉体含量为5 g/L时的4.54 MPa,提高到悬浮液HA粉体含量为20 g/L时的19.92 MPa。Hydroxyapatite(HA) coatings were deposited on titanium substrate by electrophoretic deposition in suspensions with dif-ferent HA powder contents.The surface and cross-sectional morphologies and phase composition of the as-prepared coatings were characterized by scanning electronic microscopy and X-ray diffraction.The bonding strength between the coating and substrate was tested by a shear strength testing experiment.The results show that suspension HA powder content has a significant effect on the mi-crostructure of the deposited coating,and further on its sintering property and the bonding strength between the coating and substrate.The increase in suspension HA powder content is beneficial in producing dense green coating,improving the sintering process of coating and the oxidation resistance of the substrate,and consequently increasing the bonding strength.The bonding strength between the HA coating and titanium substrate can be increased from 4.54 MPa with a suspension HA powder content of 5 g/L to 19.92 MPa with a suspension HA powder content of 20 g/L.国家自然科学基金(20573086);; 国家科技支撑计划(2007BAE051304);; 厦门市科技计划(3502Z20063005)资助项

FABRICATION OF HYDROXYAPATITE/ALUMINUM OXIDE COMPOSITE COATINGS BY THE COMBINATION OF ELECTROPHORETIC DEPOSITION AND REACTION BONDING PROCESS

在金属表面用电泳沉积(electrophoretic deposition,EPD)法制备羟基磷灰石(hydroxyapatite,HA)涂层的主要问题是结合强度较低。为了提高HA涂层与基体的结合强度,先采用EPD在钛表面制得羟基磷灰石/铝(hydroxyapatite/aluminum,HA/Al)复合涂层,然后采用反应结合方法(reaction bonding process)制备羟基磷灰石/氧化铝(hydroxyapatite/aluminum oxide,HA/Al2O3)复合涂层,并与相同条件下制备的HA单一涂层进行比较研究。用扫描电镜表征涂层的表面和横截面形貌。用能量散射X射线衍射(X-ray diffraction,XRD)谱分析HA/Al2O3复合涂层的化学组成。用XRD仪研究涂层的物相组成和热稳定性。通过黏结–拉伸实验测定HA涂层与基体的结合强度。结果表明:通过850℃热处理,HA/Al复合涂层中的Al粉发生氧化反应生成Al2O3,经反应结合得到HA/Al2O3复合涂层;反应结合提高了HA涂层的致密化程度且降低了基底钛表面的氧化程度;与单一HA涂层相比,HA/Al2O3复合涂层与基底间的结合强度得到明显提高。The major problem in fabricating hydroxyapatite (HA) coating on metal substrate by electrophoretic deposition is the low bonding strength between the coating and substrate. In order to improve the bonding strength,hydroxyapatite/aluminum oxide (HA/Al2O3) composite coating was fabricated on titanium substrate using the combination of electrophoretic deposition and reaction bonding process. The HA single coating was prepared in the same conditions for comparison. Scanning electronic microscope was employed to characterize the surface and cross-sectional morphologies of the as-prepared coatings. The chemical compositions of the composite coating were analyzed through energy dispersive X-ray spectroscopy. X-ray diffraction was used to study the phase com-position and thermal stability of the as-prepared coatings. The bonding strength between the coating and substrate was tested by a shear strength testing experiment. The results show that the Al in HA/Al green coating prepared by the EPD was oxidized to Al2O3,and HA/Al2O3 composite coating was obtained using the reaction bonding process by heat treatment at 850 ℃. The reaction bonding process promotes the coating's sintering densification and improves the substrate's oxidation resistance during the heat treatment. In comparison with the HA single coating,the HA/Al2O3 composite coating exhibits much higher bonding strength.国家自然科学基金(20573086);; 国家科技支撑计划(2007BAE05B04);; 厦门市科技计划(3502Z20063005)资助项

Research Progress in the Fabrication of Metal Matrix Composites by Electrochemical Methods

［中文文摘］金属基复合材料具有高比强度、高比模量、高硬度、耐高温等一系列优点,在现代航空、航天及武器装备等领域具有广阔的应用前景。综述了近年来电化学方法制备金属基复合材料的研究进展,具体介绍了电化学渗浸、连续分步电沉积和复合电沉积3种不同的电化学工艺过程。［英文文摘］Metal matrix composites have excellent properties including high specific strength, modulus, hardness and heat resistance and have abroad application prospect in the production of modern aircraft and weapon. This article reviews the recent research progress in the fabrication of metal matrix composites by electrochemical methods. Three kinds of methods including electrochemical infiltration, continuous stepped electrodeposition and coelectrodeposition are introduced in detail.国家自然科学基金资助项目(20573086

Preparation of Co-YSZ/HAp Nano-composite Coating on Ti Substrate by Electrochemical Method

采用复合电沉积和电泳沉积两步法在钛基体上制备了Co-YSZ/HAp纳米复合涂层,与只采用电泳沉积法在钛基体上制备纳米HAp单一涂层进行了比较研究.采用场发射扫描电镜、X射线衍射和能量散射谱对复合涂层的微观形貌,纳米HAp外层表面形貌,晶相,复合涂层的断面形貌及元素组成分布进行分析研究.通过粘结-拉伸实验测定了涂层与基体的结合强度,结果表明,Co-YSZ/HAp纳米复合涂层与钛基体的结合强度明显高于纳米HAp单一涂层与钛基体的结合强度,说明复合涂层具有更好的力学性能.Co-YSZ/HAp nano-composite coating and nano-HAp single coating were deposited on Ti substrate using the combination of electrocodeposition and electrophoretic deposition, and electrophoretic depositions, respectively. Surface and cross section morphologies of the coatings were observed by scanning electron microscope. Element distribution and crystal phase of the coatings were analyzed by energy dispersive spectrum and X-ray diffraction. The adhesive strength of the coating and Ti substrate was determined by shear strength testing. The results indicate that the adhesive strength of Co-YSZ/HAp nano-composite coating and Ti substrate is higher than that of nano-HAp single coating and Ti substrate. It shows that Co-YSZ as an interlayer reduces the mismatch of the thermal expansion coefficients between HAp and titanium and Co-YSZ/HAp nano-composite coating has better mechanical properties.国家自然科学基金(20573086,200273055);; 福建省自然科学基金(E0210004)资助项

Preparation of Co-YSZ/HAp nano-composite coating on Ti substrate by electrochemical method

Co-YSZ/HAp nano-composite coating and nano-HAp single coating were deposited on Ti substrate using the combination of electrocodeposition and electrophoretic deposition, and electrophoretic depositions, respectively. Surface and cross section morphologies of the coatings were observed by scanning electron microscope. Element distribution and crystal phase of the coatings were analyzed by energy dispersive spectrum and X-ray diffraction. The adhesive strength of the coating and Ti substrate was determined by shear strength testing. The results indicate that the adhesive strength of Co-YSZ/HAp nano-composite coating and Ti substrate is higher than that of nano-HAp single coating and Ti substrate. It shows that Co-YSZ as an interlayer reduces the mismatch of the thermal expansion coefficients between HAp and titanium and Co-YSZ/HAp nano-composite coating has better mechanical properties

Preparation of YSZ/HAp nano-composite coating on Ti alloy substrate by electrophoretic deposition

[中文文摘]采用电泳沉积法在钛合金基体上制备了YSZ/HAp纳米复合涂层,用场发射扫描电镜、X射线衍射和能量散射谱对复合涂层HAp外层的表面形貌和晶相、复合涂层的断面形貌及元素组成分布进行分析研究,通过粘结-拉伸实验测定了涂层与基体的结合强度。结果表明YSZ/HAp纳米复合涂层与钛合金基体的结合强度明显高于HAp单一涂层与钛合金基体的结合强度,说明YSZ/HAp的复合缓和了HAp涂层与钛合金基体之间的热膨胀系数失配现象,改善了涂层与基体之间的结合。［英文文摘］YSZ/HAp nano-composite coating and HAp single coating were deposited on Ti alloy substrate by electrophoretic deposition.Surface and cross section morphologies of the composite coating were observed by scanning electron microscope.Element distribution and crystal phase of the composite coating were analyzed by energy dispersive spectrum and X-ray diffraction.The bonding strength between coating and Ti alloy substrate was tested by shear strength testing experiment.The results indicate that the bonding strength of YSZ/ HAp　composite coating is higher than that of HAp single coating. It shows that YSZas an interlayer reduces the mismatch of thermal expansion coefficients between HAp coating and substrate and enhances the bonding strength　of the HAp coating to the Ti alloy substrate.国家自然科学基金资助项目(20573086,200273055); 福建省自然科学基金资助项目(E0210004)