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Zr023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,与钛舍金基体结合l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觎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,其结合强度迭到48.6MPa。
The HA/ZrO2 functional gradient coatings were fabricated by net-energy-controlled plasma spraying equipment PRAXAIR 4500. The microstructure and phase of the Zr-riched gradient layer of the functional gradient coatings were investigated by H TEM, XRD, SEM. Experimental results showed, (1)there were three type of ZrO2 crystals in the Zr-riched gradient layer,including t-ZrO2 ,c-ZrO2 ,and m-ZrO2, which suggested the occurrence of a martensitic phase transformation from t-ZrO2 to c-ZrO2. The which martensitic phase transformation were responsible for the toughening of the TZP- reinforced HA/ZrO2 functional gradient coatings. (2)The Zrriched gradient layer of the coating was relative dense and adhered firmly Ti alloy. In contrast,the top-layer of the coating was relative porous with different-sized micropores. The texture of the coating was gradiently changed from dense gradient layer to the porous top layer. According to ASTM C633-79 standard,the bioactive functionally gradient coatings was 48.6MPa.