Cr-N涂层高速钢在Na3PO4水溶液中的摩擦－腐蚀电化学噪声行为

在M2高速钢表面磁控溅射制备Cr-N耐磨减摩涂层,用SEM观察涂层组织,采用XPS及GDOES分析涂层表面价态及主要元素分布情况,利用附带电化学噪声装置的微动摩擦学试验机测试涂层及基材在0.02mol/LNa3PO4溶液环境下的摩擦学性能及其同步电化学噪声变化规律,并与涂层及基材在干摩擦条件下的摩擦学性能指标进行对比.研究结果表明:涂层为双层及双组分结构,组成相为Cr+CrN:涂层在空气介质中表现出优异的耐磨减摩特性,但在Na3PO4水溶液环境下介质中,由于涂层接触区域的去钝化/再钝化以及界面点蚀使腐蚀和磨损相互加速,导致Cr-N涂层丧失了减摩及抗磨作用,失效行为完全不同于干摩擦条件.

Wear-electrochemical noise behavior of Cr-N coating on M2 HSS in Na3PO4 solution

Cr-N hard coating was synthesized on M2 HSS surface by magnetron sputtering deposition.Scanning electron microscope(SEM),X-ray photoelectron spectroscopy(XPS) and glow discharge optical emission spectroscopy(GDOES) analysis were used to characterize coating microstructure,electronic state of Cr and N elements in the surface and main elements distribution.Corrosion-wear behaviors of M2 substrate and coating sliding against corundum were studied using an electrochemical noise technique in 0.02 mol/L Na3PO4 solution.Wear behaviors of the M2 steel and Cr-N coating in ambient air were also investigated for comparison.The results show that the Cr-N coating has duplex-layer structure,where Cr and CrN are mainly of coating composition,and wear resistance of the M2 substrate in ambient air is significantly improved by the Cr-N coating.In Na3PO4 solution,as the depassivation-repassivation and interface pitting accelerate both corrosion and abrasion,the Cr-N coating has no antifriction and antiwear effect on the M2 substrate,and its failure characteristic is completely different from that of in ambient air condition.