医用钛合金超声微弧氧化工艺参数对涂层厚度及孔隙率影响

在医用Ti-3Zr-2Sn-3Mo-25Nb钛合金表面采用超声微弧氧化技术,磷酸盐电解液浓度为0.18 mol/L,研究微弧氧化的主要工艺参数电压、频率、占空比、阴阳极间距离、时间对涂层厚表面形貌、孔隙率、涂层厚度影响规律,并在此基础上,研究超声对涂层质量的影响。通过SEM、AFM观察涂层形貌,借助TT260涂层涡流测厚仪测定涂层厚度,采用ImageJ 6.0软件测定涂层表面孔隙率大小。结果表明:最佳微弧氧化电压为350 V,脉冲频率为550 Hz,占空比为20%,阴阳极间距离为55 mm,氧化时间为8 min,涂层表面为多孔分布,涂层厚77.7μm,孔隙率为22%。超声波引入,增加涂层厚度,可使生物涂层厚度分布更均匀,提高了涂层的结合强度,涂层晶粒均为纳米级的三维岛状结构,岛与岛之间为连续结构。

Influence of micro-arc oxidation process parameters on the coating thickness and porosity

Biological coating was prepared on medical titanium alloy by micro-arc oxidation.The electrolyte phosphate concentration was 0.18 mol/L.The influencing micro-arc oxidation process parameters: voltage,frequency,duty cycle,distance between the cathode and anode,and time on the surface morphology,porosity and thickness of coating were investigated.The effect of ultrasound on coating quality was assessed.The surface microstructure was observed by SEM and AFM.The coating thickness was determined with the help of TT260 coating eddy current thickness gauge,and the porosity of coating surface was measured by Image J 6.0 software.The results show that the best micro-arc oxidation voltage is 350 V,the pulse frequency is 550 Hz,the duty ratio is 20%,the distance between cathode and anode is 55 mm,and the oxidation time is 8 min.The coating surface is porous with the coating thickness of 77.7 μm and the porosity of 22%.Introduction of ultrasound increases the coating thickness and binding strength,and the thickness distribution of biological coating is more uniform.The coating grains are nanoscale three-dimensional island-like structures,and the island-island connection is a continuous structure.