Tribological properties of Ni–B–TiO2 sol composite coating elaborated by sol-enhanced process: abrasive wear and impact wear

摘要

The development of composite coating with higher dispersive second phase is a crucial goal to achieve its performance against wear. In this respect, an interesting experimental investigation on the behavior of Ni-B-TiO2 sol composite coating towards scratching, sliding and impact loadings was performed. The adhesive strength was determined by progressive scratch test, while the tribological behavior was assessed through rotating and reciprocating sliding tests, as well as the impact-sliding tests. The in-situ formation of TiO2 nanoparticles in Ni-B bath, which is a recently invented technique, significantly improves the scratch response of the composite coating and its abrasive wear resistance. Indeed, the composite coating appears exempt from delamination after both scratch tests and pin-ondisk test, contrary to the pure Ni-B coating. Regarding the impact wear resistance, it was found that the wear severity and damage mechanisms depend strongly on the impact angle, which in turn is controlled by the solicitation type. The SEM observations accompanied with EDS analysis were carried out inside the wear scars to clearly understand the relationship between the surface damage and the contact angle.