电流密度对电结晶羟基磷灰石生物涂层性能的影响

改变电流密度在钛合金表面电结晶出磷酸钙预涂层,经碱液处理转变为羟基磷灰石（ｈｙｄｒｏｘｙａｐａｔｉｔｅ,ＨＡ）。扫描电镜（ＳＥＭ）,Ｘ射线衍射（ＸＲＤ）分析及拉伸实验与模拟体液实验表明：小电流密度预涂层为致密片状ＣａＨＰＯ４－２Ｈ２Ｏ,随电流密度增加涂层为疏松、细针状Ｃａ３（ＰＯ４）２－ｎＨ２Ｏ,但经过碱液处理都转变为羟基磷灰石;羟基磷灰石涂层的拉伸强度随电流密度增加而降低,在模拟体液中的溶解较弱     

钛基材上电化学沉积羟基磷灰石

通过电沉积法在经过阳极氧化的钛基材表面沉积磷酸钙盐涂层,再经碱热处理使磷酸钙涂层转变为羟基磷灰石涂层。扫描电镜(SEM)观察了阳极氧化后生成的TiO2纳米管的微观结构,以及生成的羟基磷灰石的形貌。X射线衍射仪(XRD)分析了涂层的相组成,同时测定了涂层与基体的结合强度。试验结果表明:电沉积涂层CaHPO4·2H2O经碱处理后转变为羟基磷灰石;电沉积添加双氧水与钛基材经过阳极氧化后使得涂层与基体结合强度有所提高。模拟体液浸泡试验表明涂层具有良好的生物活性。     

TiO2添加剂对等离子喷涂生物涂层HAP结合强度的影响

主要研究医用钛合金仿人类关节表面改性的课题。采用等离了喷涂技术,以Ｔｉ６ＡＩ４Ｖ为基体,在表面喷涂一定厚度的与肌肉容易长合的羟基磷灰石（ＨＡＰ）涂层,为了提高涂层的结合强度,加入了ＴｉＯ２添加剂。研究了不同含量的添加剂对涂层结合强度的影响,通过对涂层结合强度测试结果表明,ＴｉＯ２添加剂的加入大大提高了涂层的结合强度,而且ＴｉＯ２添加剂含量的不同,结合强度值也不同。用扫描电镜（ＳＥＭ）观察了涂层的断口形貌,发现涂层发生了部分韧化,主要是未熔的ＴｉＯ２在涂层中起到了增韧的作用。用Ｘ身线衍射（ＸＲＤ）分析了涂层的相结构,发现ＴｉＯ２添加剂直接或间接地使ＨＡＰ分解产生了新相,主要有α－ＴＣＰ等相,形成了相变韧化。     

Formation and Characterization of Hydroxyapatite Coating Prepared by Pulsed Electrochemical Deposition

采用交流脉冲沉积法在AZ91D镁合金表面合成了羟基磷灰石涂层。考察了交流脉冲电压、沉积时间及电解液添加剂等电化学沉积参数对羟基磷灰石涂层的形貌、微观结构、元素组成及电化学性能的影响。结果表明,当脉冲电压为110 V时,纳米级别的羟基磷灰石涂层表面更为均匀,孔隙度更小,且其XRD的特征衍射峰更为突出。当电解液中添加了NaN O3和H2O2后,羟基磷灰石颗粒和涂层表面形貌均得到优化;同时,极化曲线和交流阻抗测试结果表明该涂层在模拟体液中的耐蚀性能提高。浸泡实验结果表明,该涂层有利于诱导羟基磷灰石的形成,从而提高涂层的生物活性。     

交流脉冲电沉积羟基磷灰石涂层的制备及其性能(英文)

采用交流脉冲沉积法在AZ91D镁合金表面合成了羟基磷灰石涂层。考察了交流脉冲电压、沉积时间及电解液添加剂等电化学沉积参数对羟基磷灰石涂层的形貌、微观结构、元素组成及电化学性能的影响。结果表明,当脉冲电压为110 V时,纳米级别的羟基磷灰石涂层表面更为均匀,孔隙度更小,且其XRD的特征衍射峰更为突出。当电解液中添加了NaN O3和H2O2后,羟基磷灰石颗粒和涂层表面形貌均得到优化;同时,极化曲线和交流阻抗测试结果表明该涂层在模拟体液中的耐蚀性能提高。浸泡实验结果表明,该涂层有利于诱导羟基磷灰石的形成,从而提高涂层的生物活性。     

微束等离子喷涂氧化锆增韧羟基磷灰石复合涂层

采用微束等离子喷涂方法,在Ti-6Al-4V基体上制备了羟基磷灰石 氧化锆(70HA-30ZrO2,质量分数,%)复合涂层.将复合涂层置于模拟体液中分别浸泡了3,7,14,28 d并观察表面磷灰石的生长情况以评价涂层生物活性.采用扫描电镜(SEM)和X射线衍射(XRD)分析技术对涂层浸泡前后的表面形貌和相组成进行了研究.结果表明,涂层中ZrO2主要以立方相存在;喷涂过程中羟基磷灰石(HA)出现了一定的分解,产生大量的α-Ca3(PO4)2杂质相.HA涂层熔化效果很好,但涂层中有未熔化的ZrO2颗粒.涂层在模拟体液中浸泡28 d后表面可以形成磷灰石,说明涂层具有很好的生物活性.     

Ca-P涂层在镁合金表面的形成特征

用化学方法在AZ91镁合金表面沉积二水磷酸氢钙涂层以提高镁合金在模拟体液中的生物降解能力。运用扫描电镜、X射线衍射对该涂层在模拟体液中浸泡前、后的显微组织进行分析。结果表明,在预钙化过程中形成的二水磷酸氢钙涂层呈现出两种不同的形貌。预钙化过程中钙化溶液的滴定速度强烈地影响预钙化涂层的形貌。随着钙化涂层在模拟体液中浸泡时间的延长,二水磷酸氢钙的衍射峰逐渐消失,羟基磷灰石在基底表面析出,表明二水磷酸氢钙在浸泡过程中发生溶解。详细讨论了二水磷酸氢钙涂层的结构以及羟基磷灰石涂层的形成机制。     

钛合金表面声电沉积／碱热处理法制备HA涂层研究

为了使钛合金（Ti-6Al-4V）具有生物活性，可在其表面施加生物活性羟基磷灰石（HA）涂层。对比了声电沉积法和碱热处理法实验结果，采用扫描电镜（SEM）、X射线衍射仪（XRD）、电子能谱（EDS）、傅立叶红外透射光谱（FTIR）以及划痕测试等进行了分析。结果表明，直接采用声电沉积法在钛合金表面制备的羟基磷灰石涂层，经热处理后存在龟裂剥落现象；通过碱热处理法，对钛合金基体表面进行预处理，然后，借助声电沉积法，在钛金属表面沉积了透钙磷石涂层，经热碱液处理转变成的羟基磷灰石涂层，涂层完整，未出现剥落。经进一步高温烧结处理，所制涂层仍呈片状形貌，其由部分含钠的羟基磷灰石组成，而且HA涂层破坏的临界载荷未烧结前的4．365N提高至烧结后的8．175N。     

钛合金表面声电沉积/碱热处理法制备HA涂层研究

为了使钛合金(Ti-6Al-4V)具有生物活性,可在其表面施加生物活性羟基磷灰石(HA)涂层.对比了声电沉积法和碱热处理法实验结果,采用扫描电镜(SEM)、X射线衍射仪(XRD)、电子能谱(EDS)、傅立叶红外透射光谱(FTIR)以及划痕测试等进行了分析.结果表明,直接采用声电沉积法在钛合金表面制备的羟基磷灰石涂层,经热处理后存在龟裂剥落现象;通过碱热处理法,对钛合金基体表面进行预处理,然后,借助声电沉积法,在钛金属表面沉积了透钙磷石涂层,经热碱液处理转变成的羟基磷灰石涂层,涂层完整,未出现剥落.经进一步高温烧结处理,所制涂层仍呈片状形貌,其由部分含钠的羟基磷灰石组成,而且HA涂层破坏的临界载荷未烧结前的4.365 N提高至烧结后的8.175N.     

阴极沉积法制备Ca-P涂层研究

用阴极沉积法,以模拟体液(R-SBF)与Ca(NO3)2·4H2O-NH4H2PO4盐溶液(CP溶液)作为电解液,在经抛光后的钛片表面沉积生物活性Ca-P涂层.结果表明:在两种电解液中沉积的Ca-P涂层形貌不同;沉积层都是含有CO32-的Ca-P盐;两种Ca-P涂层的晶体结构有一定区别,在RSBF中沉积的涂层由磷酸八钙(OCP)和无定型磷灰石组成,在CP溶液中沉积的涂层除了磷酸八钙和无定型的磷灰石外,还含有少量羟基磷灰石(HA).     

Study of fluorhydroxyapatite coatings on carbon/carbon composites

Fluorhydroxyapatite coatings were prepared on the surface of carbon/carbon composites using the combined action of ultrasonic-electrodeposition and ion exchange. The morphology, structure and composition of the prepared coatings after ion exchange were investigated by scanning electron microscopy, X-ray energy spectrum analysis, infrared spectroscopy and X-ray diffraction. Results show that the crystallinity of the coating as well as the intensity of the diffraction peaks (112) and (300) of hydroxyapatite increased, whereas the intensity of the diffraction peaks of tricalcium phosphate decreased. The small lamellar crystals were converted into large ones. The fluorine content in the coating was 4.59%. The bonding strength between the coating and the carbon/carbon matrix increased slightly after immersion, reaching 4.12 MPa. The mechanism of the ion exchange during which hydroxyapatite turned into fluorhydroxyapatite is discussed.     

Enhancement of adhesion bonding between titanium metal and electrodeposited calcium phosphate

A novel hydroxyapatite/rutile coating was prepared on a titanium substrate. Initially, an amorphous calcium phosphate coating layer was electrochemically deposited on a Ti substrate. The surface morphology, chemical composition and phase identification of the coatings were investigated by the X-ray diffraction and scanning electron microscopy associated with an energy dispersive spectrometer. Annealing at 700°C for 3 hrs. transforms the amorphous calcium phosphate layer into well-crystallized hydroxyapatite (HAP) and the Ti metal surface into rutile. The developed HAP/rutile composite surface layer became denser and better adhering with the substrate than the initially formed amorphous calcium phosphate. The adhesion bond strength and the hardness of the coating were extremely raised by thermal annealing.     

High-velocity oxyfuel thermal spray coatings for biomedical applications

Plasma spraying is used to produce most commercially available bioceramic coatings for dental implants; however, these coatings still contain some inadequacies. Two types of coatings produced by the high- velocity oxyfuel (HVOF) combustion spray process using commercially available hydroxyapatite (HA) and fluorapatite (FA) powders sprayed onto titanium were characterized to determine whether this relatively new coating process can be applied to bioceramic coatings. Diffuse reflectance Fourier transform infrared (FTIR) spectroscopy, x- ray diffraction (XRD), and scanning electron microscopy (SEM) were used to characterize the composition, microstructure, and morphology of the coatings. The XRD and FTIR techniques revealed an apatitic structure for both HA and FA coatings. However, XRD patterns indicated some loss in crystallinity of the coatings due to the spraying process. Results from FTIR showed a loss in the intensity of the OH^∼ and F^∼ groups due to HVOF spraying; the phosphate groups, however, were still present. Analysis by SEM showed a coating morphology similar to that obtained with plasma spraying, with complete coverage of the titanium substrate. Interfacial SEM studies revealed an excellent coating-to-substrate apposition. These results indicate that with further optimization the HVOF thermal spray process may offer another method for producing bioceramic coatings.     

PLASMA SPRAYED Ti AND HA COATINGS： A COMPARATIVE STUDY BETWEEN APS AND VPS

Titanium (Ti) and hydroxyapatite (HA) coatings have been prepared via air (APS) and vacuum plasma spraying (VPS), and then their composition, structure, bonding strength and bioactivity were examined. The results obtained reveal that in APS process many of Ti were oxidized, but in VPS the oxidization was avoided. VPS Ti coating possesses better bonding condition than APS Ti coating. As for HA coating, higher crystallinity has been obtained while the coating was deposited by VPS as compared with APS. The simulated body fluid (SBF) tests show that both of APS and VPS HA coatings possess good bioactivity. As compared with APS, VPS is recommended as a better method to deposit Ti and HA coatings that can be applied as hard tissue replacement implants.     

多孔ZrO2/HA医用钛合金微弧氧化复合陶瓷膜层生物力学性能研究

为了获得具有生物力学性能的陶瓷膜层材料并满足临床医学上的需要。以Ti6Al4V钛合金为基体材料,通过微弧氧化工艺方法在电解液中制备氧化锆和羟基磷灰石复合陶瓷膜层材料。利用能谱分析仪和扫描电镜分析膜层结构特点。建立并改进了多孔性膜层力学性能数学模型,利用理论计算与实验测试相结合的方法对膜层相关生物力学性能进行了研究。实验结果表明,氧化锆/羟基磷灰石医用钛合金复合陶瓷能够取得比单一的羟基磷灰石陶瓷膜层更好的生物力学性能。生物陶瓷力学性能与孔隙率及生成的新相有关,通过实验与理论模型相结合的方法能够更好的对生物陶瓷膜层力学性能进行研究,所建立数学模型科学合理,具有一定理论意义。     

Plasma spraying of combustion flame spheroidized hydroxyapatite (HA) powders

Tailoring powder characteristics to suit the plasma spray process can alleviate difficulties associated with the preparation of hydroxyapatite (HA) coatings. Commercial HA feedstock normally exhibit an angular morphology and a wide particle size range that present difficulties in powder transport from the powder hopper to the plasma spray gun and in nonuniform melting of the powders in the plasma flame. Hence, combustion flame spheroidized hydroxyapatite (SHA) was used as the feedstock for plasma spraying. Spherical particles within a narrow particle size range are found to be more effective for the plasma spray processes. Results show coatings generated from spheroidized HA powders have unique surface and microstructure characteristics. Scanning electron microscope (SEM) observation of the coating surface revealed well-formed splats that spread and flatten into disc configurations with no disintegration, reflecting adequate melting of the HA in the plasma and subsequent deposition consistency. The surface topography is generally flat with good overlapping of subsequent spreading droplets. Porosity in the form of macropores is substantially reduced. The cross-section microstructure reveals a dense coating comprised of randomly stacked lamellae. The tensile bond strengths of the SHA coatings, phase composition, and characteristics of the coatings generated with different particle sizes (125 to 75 μm, 45 to 75 μm, 20 to 45 μm, and 5 to 20 μm) showed that a high bond strength of ∼16 MPa can be obtained with SHA in the size range from 20 to 45 μm. This can be improved further by a postspray treatment by hot isostatic pressing (HIP). However, larger particle size ranges exhibited higher degrees of crystallinity and relatively higher HA content among the various calcium phosphate phases found in the coatings.     

Protection of titanium metal by nanohydroxyapatite coating with zirconia and alumina second phases

In this study hydroxyapatite (HA)/zirconia/alumina composite coatings on titanium metal was carried out using Sol-Gel dip coating and calcination process. Hydroxyapatite-Alumina-Zirconia sol, coated samples in three processes by changing final sol stirring time, aging time, calcination temperature of synthesized powder and prepared coating and rate of coating. Some parts of prepared sol were also synthesized and became powder in all three processes. Scanning electron microscopy was used to estimate the particle size of the surface and for morphological analysis. The functional group and crystallization characteristics of the powders were analyzed using (FTIR) and X-Ray diffraction (XRD). Results show that the morphology of HA-Alumina-Zirconia coatings is more homogenous in the second process with 2 hours final sol stirring time, 20 hours aging time under stirring at 60, 675°C calcination temperature for coating and 850°C for powder and 60mm/min rate of dip coating.     

可降解镁合金骨螺钉表面微弧电泳水热复合涂层的制备与性能

目的在医用镁合金骨螺钉表面构建羟基磷灰石涂层,有效控制其降解速率。方法利用微弧电泳/水热复合方法,在形貌复杂的骨螺钉表面制备涂层。该方法首先利用电解抛光对骨螺钉表面进行表面预处理,采用微弧电泳技术在其表面制备羟基磷灰石涂层,再利用水热合成对微弧电泳涂层进行封孔。利用XRD、SEM、AFM等分析手段对涂层显微结构进行分析,利用体外浸泡实验和电化学实验对涂层耐腐蚀性能及其对钙磷盐的诱导特性进行了评价。结果在电解抛光电流0.14 A、抛光时间2 min的工艺条件下进行电解抛光预处理,可以提高基体和涂层的结合性能。由于骨螺钉的特殊形状,在微弧电泳电解液中添加丙三醇,并通过调整电解液中丙三醇含量优化微弧电泳工艺(电压155 V,反应时间20 min),能有效抑制尖端放电现象,防止膜层组织疏松和大量的氧化物堆积,以及涂层剥落甚至基体烧蚀的现象。再优化水热合成工艺参数(处理液p H值8.5,反应时间1.5 h,反应温度393 K)对微弧电泳涂层进行封孔,得到微弧电泳/水热复合涂层。结论微弧电泳/水热复合涂层表面形貌为菜花状结构,由纳米棒状羟基磷灰石组装而成,均匀致密,结晶性好。电化学腐蚀测试表明,制备复合涂层后,骨螺钉的腐蚀电流密度降低了一个数量级。在模拟体液中浸泡6天,骨螺钉的形貌依然完整,说明水热复合涂层在改善生物相容性的同时,提高了骨螺钉的耐腐蚀性能。但微动摩擦磨损测试显示,水热复合封孔处理后磨损性能下降。     

Characterization of thermal sprayed hydroxyapatite powders and coatings

Calcium phosphate materials such as hydroxyapatite (HA) have biocompatible properties that can promote osteogenesis or new bone formation. Thermal spraying is an economical and effective process for coating the hydroxyapatite onto metal. It has been reported that plasma spraying changes the degree of crystallinity as well as the phase composition of the HA. This article reports the preparation and characterization of HA powders and coatings by two thermal spray processes (plasma and combustion flame) and suggests that the state of the starting powder adversely affects the coating characteristics. The raw HA powders are synthesized through a chemical reaction involving calcium hydroxide and orthophosphoric acid. Phase analysis using an X- ray diffractometer revealed that the synthesized powder consists of predominantly the HA phase. Calcined and crushed HA powders of various size ranges were fed into the plasma jet to produce HA coatings on metallic substrates. In addition, some HA powders were sprayed into distilled water by plasma spraying and combustion flame spraying to study powder melting characteristics. Other samples were plasma sprayed onto a solid rotating target to study atomization and impact behavior. The morphology of the rapidly solidified powders and thermal sprayed coatings were examined by scanning electron microscopy (SEM). An X- ray sedimentation particle size analyzer, laser diffraction particle size analyzer, and image analyzer performed the particle size analysis. Preliminary results indicate that particle cohesion, size range, and thermal treatment in the plasma affect the phase and structure of the as- sprayed coating, and some post- spray treatment may be necessary to produce a dense and adherent coating with the desired biocompatible properties.