化学法去除废旧硬质合金表面TiN涂层过程中的腐蚀行为

摘要

采用3D高景深显微镜、扫描电子显微镜和能谱分析，观察和分析废旧硬质合金表面的TiN涂层在K2C2O4+H2O2+NaOH介质中的腐蚀形貌和腐蚀产物，并研究TiN涂层的腐蚀类型及腐蚀机理。结果表明，废旧硬质合金试样在草酸钾和双氧水的碱性溶液中的反应时间超过2 h后，合金表面的TiN涂层能完全去除干净，去除时存在点腐蚀、缝隙腐蚀和均匀腐蚀等腐蚀类型。涂层中的钛以Ti(C2O4)22−的形式溶解在溶液中，氮则以NH3的形式从溶液中释放出来。%The surface corrosion appearance and corrosion products of TiN coating on cemented carbides surface in K2C2O4+H2O2+NaOH solution were analyzed by 3D digital microscope, scanning electron microscope (SEM) and energy dispersion spectrometer (EDS). In addition, the corrosion types and mechanisms of TiN coating were discussed. The results show that TiN coating can be removed completely in K2C2O4+H2O2+NaOH solution when the reaction time is more than 2 h, and pitting corrosion, crevice corrosion and uniform corrosion are founded. Ti element is dissolved in the solution as the formation of Ti(C2O4)22−and N element is released as the presence of NH3 respectively.