脉冲频率对医用钛合金微弧氧化膜微观结构和性能的影响

Effect of Impulse Frequency on Microstructure and Properties of MAO Coatings of Biomedical Titanium Alloy

摘要:

在Na2SiO3溶液体系中利用微弧氧化法制备钛合金微弧氧化陶瓷层。采用扫描电镜、X射线衍射仪、UNMT-1材料表面微纳米力学测试系统等技术手段研究不同脉冲频率下陶瓷膜的表面形貌、组成、微观摩擦磨损性能和耐蚀性能。结果表明：膜层表面有大量微孔，膜层主要由锐钛矿相和金红石相TiO2组成。随脉冲频率的升高，陶瓷膜表面孔隙率先增大后减小、平均孔径先减小后增大，膜层厚度逐渐减小。在脉冲频率为700 Hz时，膜层表面平整、孔隙分布均匀，孔隙率达到最大值、平均孔径达到最小值，其数值分别为11.04%和0.86 μm，此时，膜层耐磨性和耐蚀性较好。

Abstract:

Micro-arc oxidation coatings on biomedical titanium alloys were fabricated in an aqueous solution of Na2SiO3 at different impulse frequency. The morphology, phase composition, wear resistance and corrosion resistance of the MAO coating were studied by scanning electron microscope (SEM), X-ray diffractometry, CETR UMT Multi-Specimen Test System and IVIUM Electrochemical Workstation. The results show that the MAO coating has a large number of micropores and it is mainly composed of anatase and rutile TiO2. Within the experimental impulse frequency range, the porosity of the MAO coatings increases first, and then decreases with the frequency increasing; however, the average pore size decreases first, and then increases. The thickness of coatings decreases with the rising of frequency. When the frequency is kept at 700 Hz, the surface morphology is smooth and micropores of the MAO coating are distributed homogenously, the porosity reaches the maximum value 11.04%, and the average pore size reaches the minimum value 0.86 μm; meanwhile the best wear and corrosion resistance is obtained.