Szala Mirosław, Walczak Mariusz, Świetlicki Aleksander
Department of Materials Engineering, Faculty of Mechanical Engineering, Lublin University of Technology, 20-618 Lublin, Poland.
Materials (Basel). 2021 Dec 23;15(1):93. doi: 10.3390/ma15010093.
Metallic coatings based on cobalt and nickel are promising for elongating the life span of machine components operated in harsh environments. However, reports regarding the ambient temperature tribological performance and cavitation erosion resistance of popular MCrAlY (where M = Co, Ni or Co/Ni) and NiCrMoNbTa coatings are scant. This study comparatively investigates the effects of microstructure and hardness of HVOF deposited CoNiCrAlY, NiCoCrAlY and NiCrMoNbTa coatings on tribological and cavitation erosion performance. The cavitation erosion test was conducted using the vibratory method following the ASTM G32 standard. The tribological examination was done using a ball-on-disc tribometer. Analysis of the chemical composition, microstructure, phase composition and hardness reveal the dry sliding wear and cavitation erosion mechanisms. Coatings present increasing resistance to both sliding wear and cavitation erosion in the following order: NiCoCrAlY < CoNiCrAlY < NiCrMoNbTa. The tribological behaviour of coatings relies on abrasive grooving and oxidation of the wear products. In the case of NiCrMoNbTa coatings, abrasion is followed by the severe adhesive smearing of oxidised wear products which end in the lowest coefficient of friction and wear rate. Cavitation erosion is initiated at microstructure discontinuities and ends with severe surface pitting. CoNiCrAlY and NiCoCrAlY coatings present semi brittle behavior, whereas NiCrMoNbTa presents ductile mode and lesser surface pitting, which improves its anti-cavitation performance. The differences in microstructure of investigated coatings affect the wear and cavitation erosion performance more than the hardness itself.
基于钴和镍的金属涂层有望延长在恶劣环境中运行的机器部件的使用寿命。然而，关于常用的MCrAlY（其中M = Co、Ni或Co/Ni）和NiCrMoNbTa涂层在环境温度下的摩擦学性能和抗气蚀性能的报道却很少。本研究比较研究了HVOF喷涂CoNiCrAlY、NiCoCrAlY和NiCrMoNbTa涂层的微观结构和硬度对其摩擦学和气蚀性能的影响。气蚀试验按照ASTM G32标准采用振动法进行。摩擦学检测使用球盘摩擦磨损试验机进行。对化学成分、微观结构、相组成和硬度的分析揭示了干滑动磨损和气蚀机制。涂层对滑动磨损和气蚀的抗性按以下顺序增加：NiCoCrAlY < CoNiCrAlY < NiCrMoNbTa。涂层的摩擦学行为取决于磨料刻槽和磨损产物的氧化。对于NiCrMoNbTa涂层，磨损后会出现氧化磨损产物的严重粘着涂抹，最终导致最低的摩擦系数和磨损率。气蚀始于微观结构的不连续性，最终导致严重的表面点蚀。CoNiCrAlY和NiCoCrAlY涂层呈现半脆性行为，而NiCrMoNbTa呈现韧性模式且表面点蚀较少，这提高了其抗气蚀性能。所研究涂层微观结构的差异对磨损和气蚀性能的影响大于硬度本身。
