Stellite 6 (Co-29.5%Cr-5%W-1.2%C in wt%) is traditionally used as a hardfacing material in the primary circuit of pressurised water reactors (PWRs) due to its good corrosion and wear resistance in water at up to 300 °C. In this study, pin-on-disc type sliding contact tribocorrosion testing was conducted on HIPed Stellite 6 at 20 °C and 250 °C using a bespoke tribometer to simulate a primary circuit environment. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to characterize, for the first time, the material affected by tribocorrosion. Whilst the material loss increases by 16–39 times when the test temperature is increased from 20 °C to 250 °C, the mechanisms of degradation and deformation remain largely unchanged. Furthest from the sliding contact, strain is principally accommodated by the deformation-induced transformation of the γ Co-based matrix to ε-martensite. Closer to the sliding contact, the ε-martensite phase accommodates further strain via twinning and dislocation slip. At the sliding contact the intense deformation generates a nanocrystalline structure. The tribologically affected material is resistant to plastic strain localisation; this confines wear to the nanoscale where the synergistic effects of chemical degradation and mechanical deformation permit the removal of nanoscale particulates (corrosion enhanced nanowear (tribocorrosion)). The increased wear rate at 250 °C is attributed to a temperature dependent increase in corrosion enhanced nanowear. The degradation mechanisms revealed are important for the design of future hardfacings.

Stellite 6（Co-29.5％Cr-5％W-1.2％C，按重量％计）传统上在压水反应堆（PWR）的一次回路中用作堆焊材料，因为它在高温下具有良好的腐蚀和耐磨性至300°C。在这项研究中，使用定制的摩擦计在20°C和250°C的HIPed Stellite 6上进行了针对盘式滑动接触摩擦腐蚀试验，以模拟主电路环境。透射电子显微镜（TEM），扫描电子显微镜（SEM）和X射线衍射（XRD）首次用于表征受摩擦腐蚀影响的材料。当测试温度从20°C升高到250°C时，材料损失增加了16-39倍，而降解和变形的机理基本保持不变。离滑动接触最远 应变主要通过基于γCo的基体向ε马氏体的形变诱导转变来适应。ε-马氏体相更接近滑动接触，通过孪晶和位错滑移来承受进一步的应变。在滑动接触时，剧烈的变形会产生纳米晶体结构。受摩擦影响的材料可抵抗塑性应变的局限性。这将磨损限制在纳米级，其中化学降解和机械变形的协同作用允许去除纳米级颗粒（腐蚀增强的纳米磨损（摩擦腐蚀））。250°C时磨损率的增加归因于腐蚀增强纳米磨损的温度依赖性增加。揭示的降解机制对于未来堆焊层的设计很重要。