TC4钛合金真空脉冲渗氧腐蚀性能的研究

Study on Corrosion Behavior of Vacuum Pulse Oxidation for TC4 Titanium Alloy

采用真空脉冲渗氧的方法在Ti6A14V钛合金表面制备渗氧层,通过失重法、电化学测试及扫描电镜分析对渗氧层腐蚀性能进行了研究。结果表明,渗氧层表面形貌为均匀致密的凹坑结构,在50 mL/L HF+200 mL/L HNO3混合体系中进行加速腐蚀后膜层表面基本保持完好,其腐蚀速率是基体腐蚀速率的1/13,自腐蚀电位由基体的-0.763 V提高到-0.483 V,腐蚀电流降低两个数量级,真空脉冲渗氧能极大地改善钛合金的耐腐蚀性。

The oxide layer was prepared on the surface of TC4 titanium alloy by a process of vacuum pulse oxidation. The corrosion behavior of oxide layer was analysed by mass loss, electrochemical tests and SEM. The results show that the surface morphology appears uniform concave structure, oxide film layer is basically undamaged after accelerating corrosion in 100 mL/L HF＋500 mL/L HNO3 system; the corrosion rate of oxide layer is about 1/13 that of the TC4 substrate; the corrosion potential of TC4 titanium alloy is increased from -0.763 V to -0.483 V and corrosion current density decreases two orders of magnitude. It can be feasible to make use of vacuum pulse oxidation to improve the corrosion resistance.