热喷涂HA复合涂层的组织分析

Analysis on microstructure of hot sprayed HA composite coating

为了制备羟基磷灰石(HA)复合涂层,采用化学沉淀法制备羟基磷灰石粉末,对制备的超细粉末加入PVA溶液充分搅拌、干燥、研磨和过筛,制备出微米级、近似球状的、在等离子送粉器中容易流动的羟基磷灰石粉末.利用等离子喷涂和电弧喷涂的复合喷涂方法制备出羟基磷灰石不锈钢复合涂层和氧化铝不锈钢复合涂层,并通过扫描电镜分析了涂层的组织形态.结果表明,羟基磷灰石粉末比重很轻,不易进入等离子弧中心而被融化,等离子弧将羟基磷灰石粉末加热并载入电弧喷涂气流中,由不锈钢雾化液滴一并打在基体上形成复合涂层.对于氧化铝/不锈钢涂层和复合涂层,2种粒子虽然分布不均匀,但却获得了良好的冶金结合.

In order to prepare the hydroxyapatite （HA） composite coating, a chemical precipitation method was used to fabricate the HA powder. The obtained ultrafine powder was added into the PVA solution, and then through sufficiently stirring, drying, grinding and sieving, the approximately spherical HA powder with micron grade and good fluidity in plasma powder feed unit was fabricated. The combined plasma and arc spraying method was used to prepare both HA/stainless composite coating and alumina/stainless steel composite coating, and the microstuctures of the coatings were analyzed by scanning electron microscope. The results show that the HA powder has low specific weight, and will not easily enter the plasma arc center and be melted. The HA powder can be heated by plasma arc and then carried into the arc sparying airflow. Furthermore, the HA powder will be deposited on the substrate together with the stainless steel atomization droplets to form composite coating. It is also noted that although two types of particles distribute inhomogeneously, a good metallurgical combination can be obtained.