2011/1/1 Surface coating

Abrasive Wear of Flame Sprayed and Fused NiCrBSi Alloys

NiCrBSi alloys are often used in thermal spraying because of their good wear and corrosion resistance even at temperatures over 500° C. Experience has proved these alloys are a good choice for components in the presence of hard particles. The main wear mechanism here is abrasive wear caused by hard particles. Some examples are wear plates exposed to impact sliding; extruders, screw conveyors or mixer parts exposed to grooving; fans, rotor wheel blades or impellors transporting sand/granular material at temperatures over 500° C; or pump parts exposed to fluid containing sand. In spite of such widespread use of NiCrBSi alloys in thermal spraying, their abrasive wear resistance is still not fully understood. In order to better understand, a series of sprayed and fused NiCrBSi coatings with hardness from 36 to 62 HRC were tested for abrasive wear according to ASTM G65-4 norm and the wear volumes achieved are presented. Tribological and metallographic analysis of track wear was done in order to better understand how microstrcture and hardness of NiCrBSi coatings influence abrasive wear mechanisms. These results are compared to results previously published.