The Study on Tribology and Surface Interface Characterization of Fe based Alloy Coating Deposited by HVOF Method

Abstract

Thermally Sprayed Coatings of iron based alloy powders are widely used to improve the properties such as surface hardness, wear resistance of a variety of substrate material. A unique Fe based alloy coating was thermally sprayed on to gray cast iron substrate by HVOF method under controlled conditions. Microstructure and the micro abrasive wear performance of the coating were characterized by Optical microscope, Video Measuring system as well as Non contact surface roughness testing analysis used. The dense layered coating had porosity levels below 1.5% and a high surface hardness of the order of 920 HV0.1. The coating has exhibited excellent wear resistance when subjected to micro abrasion wear test as per ASTM G77, with block on-ring test method. The wear volume of coating was significantly lesser than the substrate wear volume, and it also demonstrated a higher coefficient of friction than the substrate. Wear performance of the coating was nearly 80% that of the substrate at 0.05N load even under severe three body abrasive conditions. Wear resistance of sliding parts such as cylinder liners can be improved greatly by this thermally sprayed Fe73Si15Ni10Cr2 coating.