The microstructure and high temperature wear performance of a nickel base hardfaced coating

In the present study, influence of microstructure on high temperature dry sliding wear behavior of nickel base hardfaced coating is discussed in detail. Using plasma transferred arc (PTA) welding process, coating of nearly 4 to 5 mm thickness was deposited on 316 L (N) stainless steel substrate without any defects. The as-deposited coating contains large quantity of precipitates (range from 100 nm to 20 μm in size) in the γ-nickel matrix which increased the hardness significantly. Sliding wear tests were carried out on the coating for different sliding distances at room temperature (RT) and also higher temperature (573 K, and 823 K). Results showed that the wear resistance of coating improved significantly with increase in test temperature, and the high wear resistance was observed at 823 K. The coating exhibited different operating wear mechanisms depending on sliding distances and also test temperature. The wear mechanisms were identified based on friction and wear values along with worn surface analysis. The operating wear mechanisms at 823 K are adhesion at shorter sliding distance and tribo-oxidation at longer sliding distance.