Microstructure and wear performance of Cobalt-based alloys produced by plasma transferred arc surfacing in molten Zn-Al-bath

摘要

Pin-on-disc sliding wear tests were conducted in molten Zn-0.18%AI (wt.%) bath at 470°C to evaluate the wear performance of cobalt-based alloys and their carbide composites processed by PTA weld-surfacing technique. The main results are as follows: 1. Wear performances of Stellite 6 and Tribaloy 800 with carbide composite materials are not good when coupled with same materials although their hardnesses are higher and their microstructures are finer than those of Stellite 6 and Tribaloy 800. 2. Wear test results from different materials combination show that as the hardness of the counterpart disk is increased, the wear rate of the Tribaloy 800 pin is usually increased. 3. Although overall wear rates of both pin and disc are similar between Stellite 6 and Tribaloy 800, wear mechanism is quite different. While harder eutectic carbides are broken and detached in Stellite 6, softer matrix is preferentially damaged without pulling out of harder phases in Tribaloy 800 during the wear testing.