The Influence of Cladding Current on the Microstructure and Wear Properties of NiAl Composite Coatings

ZrC-ZrB2/NiAl composite coatings were fabricated by using a plasma cladding process. The influence of cladding current on the microstructure and wear properties of the coatings is studied in detail. The composite coatings contain a NiAl matrix and ZrC-ZrB2 reinforcements. ZrC is found to be present in the shape of blocks, and the shape of ZrB2 is similar to that of a long rod. The size of the ZrB2 phase increases with increasing current. Thermodynamic calculation and dynamic analysis reveal that the formation mechanism for reinforcements involves diffusion and precipitation. The friction coefficient and wear volume for the composite coatings decrease with increasing current and then increase. The coating prepared at a current of 95 A shows excellent wear resistance due to its high hardness, small friction coefficient and wear volume. The wear mechanism for the substrate mainly involves adhesive wear. The wear type for coatings prepared at currents of 90 and 100 A is adhesive wear and abrasive wear, respectively. The main wear mechanism for the coating prepared using a current of 95 A is abrasive wear.