Thermal Spraying of FeB Coatings Containing h-BN Solid Lubricant

Abstract

Abstract The crushed and rounded ferroboron (FeB) powders of Fe-18.8B-0.2C-0.5Si-0.8Al (wt %) were deposited onto an aluminum substrate by thermal spraying methods to improve its tribological properties. Hexagonal boron nitride (h-BN) powders which have excellent lubricating properties like graphite were incorporated to the iron boride powders as solid lubricant by sintering process and high energy ball milling technique which allows homogeneous distribution of solid lubricants in a hard metallic matrix to obtain protective coatings with low friction coefficient. As-sprayed coatings are composed of mainly h-BN and FeB, iron matrix supersaturated with boron owing to the rapid solidification of molten droplets flattened on a substrate. The friction and wear behaviors of each coating were evaluated using ring-on-disk type wear tester under paraffin base oil condition in air atmosphere. Preliminary results revealed that iron boride powder with h-BN powder (5 wt.%) is an applicable method to produce a protective composite coating against friction and wear.