Study of the microstructure and tribological property of CoNiAlB coating with FeB phase reinforced

Abstract

In this work, the CoNiAlBx coatings were successfully prepared on 38CrMoAl steel by laser cladding technology. The effects of B content addition on the microstructure, phase composition, microhardness, and tribological properties of the coatings were systematically analyzed. We found that CoNiAlB coatings were composed of β,γ,and FeB phase. TEM results shown that the orientation relationships between FeB phase and γ phase were [—112]FeB//[12]γ. With the addition of B, the microstructure changed from cellular morphology to dendritic morphology, then generated FeB phase, the transformation of microstructure led to the improvement of the coating: The microhardness improved from 380 Hv0.3 to 790 Hv0.3, the friction coefficient reduced from 0.75 to 0.45, wear rate decreased from 3.59·10−14 m3 N−1 m−1 to 1.34·10−14 m3 N−1 m−1. The wear mechanism of CoNiAlB coatings was changed from only oxidation wear to only abrasive wear, exhibited excellent tribological property.