热处理对羟基磷灰石涂层相组成、表面形貌与结合强度的影响

Effects of post-heat treatment on phase composition,surface morphology and bond strength of hydroxyapatite coatings

羟基磷灰石(HA)涂层的喷涂及其后处理工艺对其组织结构和结合强度具有重要影响。比较了热处理对不同粒度HA涂层相组成、表面形貌与结合强度的影响,为该类涂层制备工艺的优化提供实验依据。采用等离子喷涂法在纯钛表面制备了不同粒度的HA涂层,对其进行650℃不同保温时间的后热处理。利用X射线衍射仪、扫描电子显微镜和电子拉伸机检测了涂层的相组成、表面与断口形貌及剪切结合强度等。结果表明,涂层经650℃保温0.5h热处理后,非晶相和分解相基本全部转变为结晶HA。经热处理晶化后,涂层表面生成300nm以下的微粒子,双重涂层BC表面更易形成。粗粉末涂层CC和BC热处理后的剪切强度提高,而细粉末涂层FC则相反;HA涂层的剪切断裂主要是发生在涂层与基体间的界面上。

Plasma spraying and post-heat treatment of hydroxyapatite （HA） coating have important ettects on Its microstructure, surface morphology and bond strength. This paper mainly deals with the effects of post-heat treatment on phase composition, surface morphology and bond strength of HA coatings from varied powder particles. HA coatings were prepared by plasma spraying different sizes of powders onto pure titanium substrates, and then post-heat treated at 650℃ for different time. To enhance the difference of coating crystallinities, samples were fabricated at 45kW for 38-75μm powder coating （FC） and at 35kW for 75-106μm powder coatings （CC）, respectively. N-ray diffractometer （XRD）, scanning electron microscope （SEM） and electron tensile machine were use to examine the phase composition, surface morphology and shear bond strength of samples. The results show that after the post-heat treatment at 650℃ for 0. 5h, amorphous and decomposed phases in plasma sprayed samples transformed into crystalline HA completely. At the same time, mieroparticles with size of less than 300nm were formed on coating surfaces. It was also found that the post-heat treatment caused the decrease of bond strength of CC coatings, while the decrease of bond strength of FC coatings.