The Effect of Laser Power on the Properties of M3B2-Type Boride-Based Cermet Coatings Prepared by Laser Cladding Synthesis.

Zhaowei Hu,Yuantao Zhao,Wenge Li

doi:10.3390/ma13081867

Abstract

Boride-based cermet can serve as a good protective coating for low-corrosion and wear-resistant materials, such as carbon steels, due to their mechanical and chemical properties. In this study, M3B2 (M: Mo, Ni, Fe, and Cr) boride-based cermet coatings were fabricated on Q235 steel with mixed powders of Mo, B, Ni60, and Cr by laser cladding synthesis, and the effects of laser power on the properties of the cermet layer were investigated. Three laser powers (2200, 2500, and 2800 W) were used at the same scanning speed. The X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) analysis confirmed that all the coatings were composed of M3B2-type borides and {Fe, Ni} alloys. The micro-hardness, corrosion, and frictional experiments showed that the cermet coatings enhanced the corresponding performances of the Q235 steels at the three laser powers. However, the micro-hardness of the coatings decreased as the power increased, and the maximum micro-hardness value was 1166.3 HV (Vickers Hardness). The results of the corrosion and frictional experiments showed that the best performance was obtained at a laser power of 2500 W, followed by 2800 and 2200 W.

Highlights

In recent years, wear- and corrosion-resistant materials have been used in various industrial areas
Boride-based cermet composite coatings consisting of a transition metal base matrix with dispersed hard phases, such as Mo2 FeB2, WCoB, MoCoB, and Mo2 NiB2, possess high hardness, high melting points, good wear and corrosion resistance, and good optical and thermal properties [1,2,3,4,5,6]
Cr and V addition resulted in improvement of the mechanical properties, such as TRS and hardness associated with a simultaneous phase transformation of complex boride from orthorhombic to tetragonal

Summary

Introduction

Wear- and corrosion-resistant materials have been used in various industrial areas. Boride-based cermet composite coatings consisting of a transition metal base matrix with dispersed hard phases, such as Mo2 FeB2 , WCoB, MoCoB, and Mo2 NiB2 , possess high hardness, high melting points, good wear and corrosion resistance, and good optical and thermal properties [1,2,3,4,5,6]. These cermet coatings have been applied to injection molding machine parts, cutters for heat sealers, bearings for sea water pumps, offshore engineering parts, and slurry flow units in the coal-mining industry [7,8]. The addition of Fe, Co, Ti, Mn, Zr, Nb, and W did not result in structural changes, but Materials 2020, 13, 1867; doi:10.3390/ma13081867 www.mdpi.com/journal/materials

Methods

Results

Discussion

Conclusion