Influences of the microstructure on the wear resistance of cobalt-based alloy coatings obtained by plasma transferred arc process

The microstructure, substructure, and wear characteristic of cobalt-based alloy coatings obtained by plasma transferred arc (PTA) process were investigated using optical metallurgical microscope, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and dry sand abrasion tester (DSAT). The aging effect on the structure and wear resistance of the cobalt-based PTA coating was also studied. The results show that the as-welded coating consists of cobalt-based solid solution with face-centered cubic structure and hexagonal (CrFe)(7)C-3. There are a lot of stacking faults existing in the cobalt-based solid solution. After aging at 600 degrees C for 60 h, the microstructure becomes coarse, and another carbide (CrFe)(23)C-6 precipitates. As a result, the wear mass loss of the aged sample is higher than that of the as-welded sample.