Microstructure and Abrasion Resistance Mechanism of CrB Particles Reinforced MMC Coating

The CrB Particles Reinforced MMC Coating was prepared by using high velocity arc spraying (HVAS) method. Through a series of experiments, including metallographic, SEM and EPMA investigation, the microstructure and composition of the coating were analyzed in details. Additionally, the abrasion resistance mechanism of the coating was studied through field test and observation on the abrasion surface of the coating under the SEM. The results show that the microstructure of the coating is characterized by typical compact laminated structure composed of successive metal matrix and hard particles mainly of borides of chromium and oxides of chromium. The abrasion resistance mechanism of the coating lies in two aspects. One is that the hard particles scatter evenly and dispersedly in the coating, which can reinforce the coating and play a barrier role to hinder the movement of the abrasion particles. The other is that the metal matrix with well ductility and toughness make a buffer action to the impact caused by the abrasion particles, thereby the waste rate of the coating can be greatly slowed down. The results also show that the hardness, shape and quantity of the reinforced particles have magnificent influence on the abrasion resistance of the coating made in this paper.