Effect of Zr/Nb Content on the Diffusion Behaviour and Wear Resistance of In-Situ Zrc-Nbc Particles in Fe-Based Composite Coatings

Abstract

AbstractsCeramic-reinforced coatings play a pivotal role in wear-resistant applications. This study developed (Zr, Nb)C reinforced composite coatings via plasma spray welding using Fe-based alloys blended with different Zr/Nb powders. The nucleation, morphology, and strengthening mechanisms of (Zr, Nb)C particles were investigated. XRD analysis confirmed that composite coatings comprised of (Zr, Nb)C reinforced particles in the Fe-Cr matrix. Microstructural analysis revealed Zr/Nb content significantly influenced particle morphology: the presence of higher Zr promoted the formation of block-like dendritic (Nb, Zr)C particles, whereas an increase in Nb resulted in smaller spherical particles. Microhardness of composite coatings ranged from 720 HV to 880 HV, peaking at when Zr/Nb ratio was 1:1. This hardness trend aligned with wear resistance improvements, attributed to the maximum generation of uniform (Zr, Nb)C and grain refinement. The optimized Zr/Nb ratio not only eliminated the coarse microstructures but also enhanced the dispersion of carbide, demonstrating the critical role of stoichiometric control in balancing nucleation kinetics and particle morphology to achieve superior mechanical performance. The improvement in friction and wear performance was directly related to the generation of strengthening particles and their synergistic effects. These findings provide a theoretical framework for designing ceramic-metal composite coatings with tailored phase architectures.

Keywords: (Zr, Nb)C particles, in-situ, plasma spray welding, Wear resistance, composite coating