电流密度对TC11钛合金微弧氧化性能的影响

Effect of Current Density on Micro-arc Oxidation Properties of TC11 Titanium Alloy

摘要:

钛合金耐磨性和耐腐蚀性的弱点已经成为限制钛合金使用的瓶颈。在本项工作中，以硅酸钠（Na2SiO3）和钨酸钠（Na2WO4）为电解质在TC11钛合金表面生成一层微弧氧化膜。使用扫描电子显微镜（SEM）、X射线衍射（XRD）和显微硬度测试仪等观察涂层表面形貌和横截面形貌以及内外陶瓷膜层的显微硬度。与基体钛合金相比，当电流密度为9A/dm2，膜层的显微硬度得到提高，但附着力有所降低。 此外，在3.5%NaCl和30%H2SO4溶液中比较分析了膜层的电化学腐蚀和一般腐蚀，当电流密度为9A/dm2时，在30%H2SO4溶液中的膜层具有较低的自腐蚀电流密度。最后，通过SiC和膜层的对磨实验研究了膜层的磨损机理。

关键词:钛合金 微弧氧化 耐磨性 耐腐蚀性能

Abstract:

The weakness of wear resistance and corrosion resistance of titanium alloy has become a bottleneck restricting the use of titanium alloy. In this work, the micro-arc oxidation coating is performed on TC11 sample in electrolyte prepared by sodium silicate (Na₂SiO₃) and sodium tungstate (Na₂WO₄). Scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-hardness tester are used to observe the coating surface and cross-sectional morphology, micro-hardness of the inner and outer ceramic coating. The coating is mainly composed of TiO₂, γ-Al₂O₃, and Al₂TiO₅. TiO₂ consists of anatase-TiO₂ and a small amount of rutile-TiO₂. The outer coating contains a large amount of amorphous SiO₂. The electrochemical corrosion and general corrosion of the coating are comparatively analyzed in 3.5% NaCl and 30% H₂SO₄ solution, and the coating obtained in the 30% H₂SO₄ solution has a lower self-corrosion current density. Finally, the wear mechanism of the coating is studied by the anti-wear experiment with SiC.

Key words:Titanium alloy; micro-arc oxidation; wear resistance; corrosion resistance