Tribological behaviour of HVOF sprayed diamond reinforced bronze coatings

Abstract

Abstract Bronze is a well-known bearing material owing to its high ductility and favourable frictional characteristics. However, bronze is a soft metal and its hardness and wear resistance can be improved by incorporating a hard reinforcing phase in it. In the present work the preparation and characterisation of a 10\u202fwt% diamond reinforced HVOF sprayed bronze coatings on bearing steel substrate is reported. The HVOF feedstock is prepared by ball milling a mixture of the bronze and 10\u202fwt% diamond powders. The reinforced coatings were characterised for their microstructural and mechanical properties. These properties were compared with a pure bronze coating. Tribological performances of both the coatings were evaluated in ball-on-disc sliding configuration using a Cr-steel counter body. A significant improvement in the wear resistance was observed in the case of the diamond reinforced composite bronze coatings. A primary wear mechanism active in the case of pure bronze coatings was plastic deformation of the top layer of the coatings. The degree of plastic deformation reduced considerably upon addition of the diamond phase.