CrAlN涂层海水环境腐蚀磨损行为研究

采用多弧离子镀在316不锈钢上沉积Cr Al N涂层,用X射线衍射仪(XRD)和扫描电子显微镜(SEM)表征涂层的成分和结构,纳米压痕和划痕仪分别测试涂层的硬度和结合力.通过球-盘往复式摩擦磨损试验机在海水环境下测试涂层腐蚀磨损性能,并用电化学工作站实时监测其摩擦过程中的电化学特性.结果表明:Cr Al N在有摩擦的条件下,涂层极化曲线的阳极区域存在较为明显的钝化区,抑制了涂层进一步腐蚀.在阳极电位下,涂层的摩擦系数随着加载电位的增加显著降低.随着加载电位的升高,涂层的磨损量也相应地增大.在阳极电位0.5 V下的磨损量是阴极电位–1 V下的2.99倍.在0 V时,磨损促进腐蚀的损失量,约占总损失量的13.71%.在–1 V,–0.5 V,–0.25 V,OCP,0 V下的磨损机理主要为磨粒磨损和塑性变形,而在0.25 V,0.5 V下的磨损机理主要为疲劳点蚀.

Tribocorrosion Behaviors of CrAlN Coating in Seawater

The CrAlN coating was deposited on the 316 stainless steel by multi-arc ion plating. The composition and structure of coating was characterized by X-ray diffraction and scanning electron microscopy. The hardness and adhesion of the CrAlN coating was measured by using the nanoindentation device and the scratch tester. The tribocorrosion behavior of CrAlN was investigated in seawater environment. Tests were carried out in a triboelectrochemical cell using a ball-on-disk tribometer integrated with a potentistat for electrochemical control. It is found that the polarization curve of anodic area existed obvious passivated zone, which restrained further corrosion of coating during the sliding contact. The coefficient of friction decreased significantly at the anodic potential. Due to the synergism of the corrosion-wear, the wear-loss increased as the applied potential increased from -1 V to 0.5 V, synchronously. The total CrAlN coating loss at the anodic potential of 0.5 V (SCE) can be as large as 2.99 times of that at the cathodic potential of -1 V (SCE). Under the potential of 0 V, the wear-accelerated corrosion was generated, which accounted for about 13.71% of the total loss volume. At the potential (-1 V, -0.5 V, -0.25 V, OCP,0 V), the dominant wear mechanism was abrasive wear and plastic deformation while the fatigue pitting at the anodic potential (0.25 V, 0.5 V).