Tribological characteristics of composite coatings formed by laser cladding of powders of nickel self-fluxing alloy and bronze

Abstract

Microstructures, coefficients of friction, and relative wear of composite coatings based on the PG-12N-01 nickel self-fluxing alloy and PG-19M-01 bronze have been considered. It has been found that composite coatings have a complex structure. The bronze coating, which is deposited on the fillets of the nickel alloy, crystallizes in a form of dendrites with axes arranged under an angle of 45°. The nickel alloy has a globular-dendritic structure with the eutectic component crystallizing between its branches. Momentary coefficients of friction in conditions of the concentrated load are independent of the cladding rate, and their values are 0.08–0.12 depending on the load. In this case, the wear rate of coatings depends substantially on the laser cladding. Under conditions of the distributed contact, bilayer coatings have a considerable advantage, and the relative wear is reduced by several tens of times compared with single-layer ones.