Microstructure and surface wear resistance in rapidly quenched Fe–Cr–B alloy spray coatings

Fe–Cr–B alloy coatings were fabricated by thermal spraying and investigated in this research as to its wear-resistance and friction properties. The Fe–Cr–B spray-coated layers exhibited much higher wear resistance and significantly low friction coefficient in comparison with those of Fe–Cr base tool steel. The present paper reports that the presence of amorphous surface film formed during the sliding wear will be the main cause of noticeably improved friction properties and wear resistance. It was also observed that the Fe–Cr solid solution phase with supersaturated B and Si was the phase contributing to the crystalline-to-amorphous transition induced by sliding wear. These results imply the possible application of the present alloy coatings to the lubricant-free sliding systems in which the use of organic lubricants is limited or prohibited.