Microstructure and Tribological Properties of Plasma Sprayed FeCoNiCrMo and FeCoNiCrMn High-entropy Alloy Coatings
Abstract
In this study, FeCoNiCrMo and FeCoNiCrMn high-entropy alloy coatings were successfully prepared on KmTBCr12 iron substrates by plasma spraying technology. The microstructure and phase composition of the coatings were analyzed, and the effects of spraying current and spraying distance on hardness, bonding strength, and porosity were systematically investigated. Additionally, the wear resistance mechanisms of the two coatings were compared. The experimental results show that both coatings exhibit a strong metallurgical interface with partially developed lamellar eutectic patterns. The critical process variables significantly impact the coating hardness, bonding strength, and porosity. Elemental distribution analysis confirms that oxide formation occurs in all metal components of the coating, which greatly improves its hardness and tribological properties. The FeCoNiCrMo coating exhibits a 2.52-fold increase in hardness compared to the substrate, which is attributed to solid-solution hardening induced by Mo additions. Under dry sliding friction conditions, the wear rates of the FeCoNiCrMo and FeCoNiCrMn coatings are reduced by 89 % and 78 %, respectively, relative to the substrate. After the coatings are applied to the substrate surface, the wear mechanism changes from adhesive wear to abrasive and fatigue wear.