等离子体辉光放电制备W-Mo共渗层在还原性酸中耐蚀性研究

Corrosion behavior of W-Mo co-penetrated layer produced by glow discharge plasma technique in reducing acid

摘要:

在β相变点以下,通过空心阴极等离子体辉光放电技术,在Ti6Al4V合金表面形成W-Mo共渗层来提高钛合金基体在还原性酸中的耐蚀性。分别利用扫描电子显微镜、能谱仪和X射线衍射仪对试样的表面形貌、成分分布和相组成进行分析。结果显示在Ti6Al4V合金表面形成一层约23μm厚,由AlMoTi2 和 TixW1-x物相组成的共渗层。利用电化学工作站,在常温静态条件下,对试样在还原性酸(硫酸和盐酸)中进行耐蚀性研究。结果表明,经过共渗处理的试样在还原性酸中,能保持稳定的腐蚀电位并且其腐蚀电流密度仅为原始试样的1/10 和 1/6。此外,相较于钛合金基体,处理后的试样表面没有发现腐蚀产物和裂纹,表明没有腐蚀脱落现象发生。因此,在保证基体基本性能的前提下,钛合金试样的耐蚀性能明显提高。

Abstract:

To improve the corrosion resistance of Ti6Al4V alloys in acid solution, a W-Mo co-penetrated top layer was prepared using hollow-cathode glow discharge plasma technique below the β phase transition point. The surface morphology, chemical composition and crystal structure of the coatings were determined by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray power diffraction (XRD), respectively. It indicated that a dense co-penetrated layer was produced with maximum thickness of approximately 23 μm. The layer was composed of AlMoTi2 and TixW1-x phases. The static corrosion test was conducted in acid (H2SO4 and HCl, respectively) at room temperature (RT) by using the electrochemical workstation. The results showed that the W-Mo co-penetrated layer could achieve relatively stable corrosion potential in reducing acid and the Icorr of co-penetrated layers occupy merely 1/10 and 1/6 that of Ti6Al4V substrates. In addition, there is barely any corroded product and crack on the corroded surface of co-penetrated layers, indicating no corroded shedding phenomenon occurred. So the corrosion resistance are obviously improved in the premise of keeping the basic properties of the substrate.