氧化锆增韧HA/ZrO2功能梯度涂层的TEM分析

利用净能量控制的PRAXAIR4500型等离子喷涂系统,在钛合金基体上制备出HA/ZrO2功能梯度涂层,采用HTEM、XRD、SEM等对涂层过渡层ZrO2相的结构特征进行分析.结果表明:(1)富锆的过渡层存在ZrO2 3种晶型,主要以四方氧化锆为主,含有少量的立方氧化锆及微量的单斜氧化锆和CaZrO3,单斜氧化锆的出现说明材料内发生了四方氧化锆向单斜氧化锆马氏体相变,这种马氏体相变有利于提高HA材料的韧性;(2)生物活性功能涂层的富锆过渡层致密,与钛合金基体结合紧密,纯羟基磷灰石的表面层具有典型的多孔结构特征,整个涂层沿垂直基体方向从过渡层致密结构向表面层多孔结构过渡;涂层的这种结构特征有利于改善功能梯度涂层的综合性能,提高涂层与基体的结合强度,其结合强度达到48.6MPa.     

梯度结构羟基磷灰石生物活性涂层的性能

采用等离子喷涂系统在Ti6Al4V钛合金基体表面制备出真有梯度结构的羟基磷灰石生物活性梯度涂层,利用纳米硬度计等手段分析了生物活性涂层的梯度结构．结果表明：金属基体与陶瓷界面区域的弹性模量和硬度呈梯度变化;生物活性功能涂层的表面具有典型的多孔结构特征,整个涂层沿垂直基体方向从底层致密结构向表面层多孔结构过渡;涂层的成分从生物稳定性的底层至生物活性的表面层呈梯度变化,涂层表面成分为具有生物活性的羟基磷灰石．涂层的这种结构特征保持了涂层的生物活性,提高涂层与基体的结合强度（48．6MPa）。     

电泳沉积制备羟基磷灰石／生物玻璃梯度涂层的研究

本文研究了羟基磷灰石颗料，生物玻璃颗粒在醋酸介质中的电泳沉积规律，利用它们不同的沉积规律设计了羟基磷灰石／生物玻璃梯度沉积装置，用电子探针分析了涂层横截面元素分布，表明所设计的装置可实现羟基磷灰石和生物玻璃的梯度涂层。     

喷涂功率对真空等离子喷涂羟基磷灰石涂层的影响

本文采用真空等离子喷涂设备，在不偷呐涂功率下制备了羟基磷灰石涂层，研究了热喷涂功率对羟基磷灰石涂层材料学特征的影响。实验中，使用Ｘ射线衍射仪，测定了涂层的相组成。使用扫描电子电镜，观察了羟基磷灰石涂层的表面形貌。研究结果表明，热喷涂功率对羟基磷灰石涂层的结构有着重大的影响。一方面，随着热喷涂功率的提高，涂层的非晶化加剧，涂层中非晶态的羟基磷灰石含量不断增大。另一方面，随着热喷涂功率的提高，羟基磷灰     

羟基磷灰石生物涂层的复合制备与生物相容性

采用等离子喷涂CaHPO4和水热处理复合制备羟基磷灰石生物涂层,研究了羟基磷灰石涂层的结合强度和溶解性,用成骨细胞考察了生物相容性,结果表明,喷涂涂层由C aHPO4,β－Ca2P2O7和α-C3(PO4)2组成,其相比例,结晶性和形貌取决于喷涂电流和喷涂距离;喷涂涂导经过水热处理可转化为针状结晶的缺钙羟基磷灰石,这种羟基磷灰石涂层具有高的结合强度和稳定性,与成骨细胞的生物相容性良好。     

等离子喷涂羟基磷灰石涂层的结合强度

讨论了影响和制约等离子喷涂羟基磷灰石涂层与钛合金基底之间结合强度的主要因素,总结了提高涂层结合强度的方法及相关研究的进展。     

微束等离子喷涂羟基磷灰石涂层

采用微束等离子喷涂(MPS) 在Ti6Al4V基体上制备了羟基磷灰石(HA)涂层, 并以大气等离子喷涂(APS)为对照. 利用光学显微镜、SEM和XRD分析技术对MPS涂层形貌、相组成和结晶度进行了研究. 结果表明: 在微束等离子喷涂过程中, HA 的分解程度比大气等离子喷涂有显著降低, 除了HA相, 仅形成β-TCP相和非晶相. MPS涂层的结晶度主要受喷涂距离的影响. 喷涂距离较短(<80mm)时, 涂层结晶度高于APS方法制备的涂层. 喷涂距离在130mm时, 涂层结晶度低. 大气等离子喷涂层含有β-TCP、α-TCP、TTCP、CaO和非晶. MPS涂层分解较APS少的主要原因是喷涂过程中HA粒子过热不严重.     

氧化锆基羟基磷灰石梯度涂层材料的研究

本文采用涂覆－烧结法制备了一种以氧化锆为基体的生物玻璃－羟基磷灰石梯度涂层材料，并对其热学、力学性能进行了测试。实验发现，在生物玻璃－羟基磷灰石梯度设计时，羟基磷灰石含量对复合体材料的热膨胀性能有着较大的影响。这种影响的原因是，随着羟基磷在石含量的变化，复合体材料的结构发生改变，从玻璃相为主晶相向羟基磷灰石为主晶相转变。文中对梯度涂层各层中的热尖力进行了计算，其结果与涂层－基体的结合强度相吻合。     

HA(ZrO2)/316L不锈钢纤维对称功能梯度生物材料

制备了HA(ZrO2)/316L不锈钢纤维对称功能梯度材料(FGM),316L不锈钢纤维的含量(体积分数)按20%→10%→0→10%→20%呈轴向对称梯度变化.分析了材料的微观结构和微区元素含量,研究了材料的性能与316L不锈钢纤维含量的关系.结果表明,在HA(ZrO2)/316L不锈钢纤维对称FGM中,316L不锈钢纤维在微观上呈无序和均匀分布状态,它被包裹于HA(ZrO2)基体中,两者紧密结合.316L不锈钢纤维与HA(ZrO2)基体间的界面表现为部分凹凸不平,紧紧地咬合在一起.在FGM基体中发生了微量的韧化相Fe元素扩散,在韧化相316L不锈钢纤维不发生基体相Ca、P元素的扩散,基体与韧化相之间不发生化学反应.随着316L不锈钢纤维含量的增加,HA(ZrO2)/316L不锈钢纤维复合材料的断裂韧性和弹性模量逐渐增加,体现了FGM中各梯度层的力学性能缓和设计.按Miao模型计算HA(ZrO2)/316L不锈钢纤维FGM中的残余热应力为515 MPa,FGM的增韧机理主要为纤维的拔出增韧和层间的裂纹偏转增韧.     

ZrO2—HAP变组成梯度生物材料的制备

本文采用溶胶－凝胶法合成了羟基磷灰石（ＨＡＰ）细粉,用化学共沉淀法制备了氧化钇稳定的氧化锆细粉。以ＨＡＰ和氧化钇稳定的氧化锆为原料制备了梯度生物材料。通过部分稳定的氧化锆的相变增韧和微裂纹增韧改善了生物材料的力学性能;通过ＸＲＤ、ＥＰＭＡ等揭示了材料的矿物组成和显微结构。结果表明,与磷酸盐生物陶瓷相比,ＨＡＰ－ＺｒＯ２（Ｙ２Ｏ３）梯度生物材料具有良好的力学性能。     

等离子喷涂制备HA/ZrO2复合涂层

采用等离子喷涂技术,在Ｔｉ－６Ａｌ－４Ｖ基体上成功地制备了羟基磷灰石／氧化锆（ＨＡ／ＺｒＯ_２）复合涂层,对涂层的微观结构、相组成和结合强度进行了研究,并以模拟体液试验评估涂层的生物活性．结果表明,复合涂层具有较为均匀的微观结构．ＨＡ／ＺｒＯ_２复合涂层的结合强度明显高于 ＨＡ涂层, ＨＡ／６０ ｗｔ％ ＺｒＯ_２涂层的结合强度高达 ２８．５ＭＰａ,为 ＨＡ涂层的 ２．２倍．复合涂层在模拟体液中浸泡一段时间后,表面覆盖一层碳酸磷灰石（ｃａｒｂｏｎａｔｅ－ａｐａｔｉｔｅ）,表明涂层具有良好的生物活性．     

Electrophoretic Depostition of Hydroxyapatite Coating

Hydroxyapatite (HAP) coatings were deposited onto titanium substrates by electrophoretic deposition(EPD) from ethanol.The results indicated that the addition of very small amount of HCl resulted in a decrease in the aging time as weel as the suspension concentration required to obtain a coating,In addition,the results revealed the existence of a critical saturated voltage (Vsat),which had significant effect on the quality of deposition ,The mean interfacial shear strenghs of HAP coatings after sintering were found to be greater than 13 MPa.     

Electrophoretic Deposition of Hydroxyapatite Coating

Hydroxyapatite (HAP) coatings were deposited onto titanium substrates by electrophoretic deposition (EPD) fromethanol. The results indicated that the addition of very small amount of HCI resulted in a decrease in the aging timeas well as the suspension concentration required to obtain a coating. In addition, the results revealed the existenceof a critical saturated voltage (Vsat), which had significant effect on the quality of deposition. The mean interfacialshear strengths of HAP coatings after sintering were found to be greater than 13 MPa.     

Cr2O3 梯度涂层的组织与耐磨性研究

采用等离子喷涂技术设计并制备了耐磨梯度涂层。涂层组织,以及显微硬度和磨损率测量结果表明,从基体到陶瓷层,通过涂层成分的逐渐变化,涂层的组织及性能均具有梯度涂层的特征。     

In vivo biological responses of plasma sprayed hydroxyapatite coatings with an electric polarized treatment in alkaline solution

The plasma sprayed hydroxyapatite coatings were post-treated by an electric polarized treatment in alkaline solution (PAS). The compositions, stabilities, surface charges, bone-like apatite formation abilities of the PAS coatings were investigated. The bioactivity of the PAS coatings was characterized in vivo. The results showed that the stabilities of the PAS coatings were improved because of the increased crystallinity and the decreased impurity phase. The bone-like apatite formation abilities were also improved after the PAS treatment because of the negative charges formed on the coating surfaces. Animal experiments showed that the PAS coatings could accelerate the initial fixation of the implant. The results indicated that the PAS is a promising post-treatment method to improve the biological properties of the plasma sprayed hydroxyapatite coatings.     

涂层基体条件对梯度涂层残余应力影响研究

采用有限元法，对结构一定的Al/Ni-ZrO2梯度涂层在基体条件改变时涂层的残余应力进行了分析，结果表明，基体材料的热膨胀系数对涂层的残余应力有显著的影响，对于基体为圆柱形的涂层，其基体与涂层界面的残余应力梯度，最大轴向拉应力均随热膨胀系数的增大而线性增大，表面纯陶瓷层与次层界面残余应力梯度则随之减小，增大基体的直径和厚度，可缓和涂层残余应力，并在基体直径为36mm,厚度为20mm时各残余应力基本稳定。     

电泳沉积HA -Ti -Y2 O3/ZrO2复合涂层的研究

为了制备均匀致密的HA -Ti -Y2 O3/ZrO2陶瓷涂层,在正丁醇介质中,以三乙醇胺为添加剂,将羟基磷灰石(HA)与Ti,Y2 O3/ZrO2按一定比例混合电泳沉积在钛基底上,得到了形貌稳定的HA -Ti -Y2 O3/ZrO2生物陶瓷涂层.研究了电场强度,电泳时间,添加剂用量对涂层品质的影响.用扫描电镜(SEM)对热处理后的涂层进行了观察,采用红外光谱仪(FTIR)和X射线仪(XRD)对涂层的形貌、组成及结构进行了表征.结果表明:在正丁醇作分散剂,三乙醇胺添加量为12 mL/L,电场强度30～60 V/cm,HA浓度为10～20 g/L,Ti为4～16 g/L,Y2 O3/ZrO2为6～12 g/L的条件下,可制得形貌较好的HA -Ti -Y2 O3/ZrO2复合陶瓷涂层.     

Laser processing of ZrO2 coatings

Potential materials for protective heat-resistant coatings are the so-called fragmentary porous ceramic layers penetrated by a net of microcracks. The fragments can be shifted easily during thermal cycling procedure, and the micro-cracks prevent the throughout crack propagation, which could destroy the coating. Laser surface processing of coatings is one of the effective ways to form the fragmentary layered structure.

The peculiarities of laser processing of ZrO₂+Y₂O₃ plasma sprayed coatings deposited onto the steel substrate with the Ni-Cr-Al-Y sub-layer alloy were investigated. The coatings were processed by CW CO₂ and Nd:YAG lasers (Fig. 1). The laser processing resulted in melting of the coating surface. The modified coating consisted of a number of macro fragments with sizes 200-500 μm and in turn they consisted of a number of micro-fragments with sizes 20-70 μm. Both types of the fragments are separated by wide (10-15 μm) or narrow (1-5 μm) cracks accordingly. The structure and some properties of the modified coatings such as heat-resistance, hardness, surface roughness, and tightness are investigated depending on the laser output parameters.