钼对激光熔覆FeCoCrNi高熵合金涂层微观结构及腐蚀行为的影响

Influence of Mo on the Microstructure and Corrosion Behavior of Laser Cladding FeCoCrNi High-Entropy Alloy Coatings.

作者信息

Li Wenjuan, Guo Wenmin, Zhang Hongling, Xu Huanhuan, Chen Liang, Zeng Junshan, Liu Bin, Ding Zhibing

机构信息

College of Mechanical and Energy Engineering, Shaoyang University, Shaoyang 422000, China.

Key Laboratory of Hunan Province for Efficient Power System and Intelligent Manufacturing, Shaoyang University, Shaoyang 422000, China.

出版信息

Entropy (Basel). 2022 Apr 12;24(4):539. doi: 10.3390/e24040539.

DOI:10.3390/e24040539

PMID:35455202

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC9028930/

Abstract

FeCoCrNi and FeCoNiCrMo high-entropy alloy powders were prepared by gas atomization. Two kinds of coatings were prepared on the surface of 304 stainless steel by laser cladding technology. The effect of Mo element on the microstructure of laser cladding FeCoCrNi coating and its corrosion behavior in 3.5 wt.% NaCl solution was investigated. Both FeCoCrNi and FeCoCrNiMo powders exhibit a single-phase FCC structure. Due to the remelting and multiple heat treatments during the preparation of the laser cladding coating, a small amount of σ and μ phases appeared in the FeCoCrNiMo coating. The microstructures of the two coatings from the bonding area to the top layer are planar, columnar and equiaxed grains, respectively. The addition of the Mo element causes the dendrite size in the middle region of the FeCoCrNiMo coating increases significantly and exhibits obvious orientation characteristics. FeCoCrNiMo coating has high corrosion potential (-0.01 ) and low current density (0.94 × 10 A/cm) in 3.5 wt.% NaCl solution, showing excellent corrosion resistance. The passivation film formed on corroded the FeCoCrNiMo coating contains high content of oxides of Cr and Mo. The addition of the Mo element enhances the compactness and pitting resistance of the passivation film.

摘要

通过气体雾化法制备了FeCoCrNi和FeCoNiCrMo高熵合金粉末。采用激光熔覆技术在304不锈钢表面制备了两种涂层。研究了Mo元素对激光熔覆FeCoCrNi涂层微观组织及其在3.5 wt.% NaCl溶液中腐蚀行为的影响。FeCoCrNi和FeCoCrNiMo粉末均呈现单相FCC结构。由于激光熔覆涂层制备过程中的重熔和多次热处理，FeCoCrNiMo涂层中出现了少量的σ相和μ相。两种涂层从结合区到顶层的微观组织分别为平面晶、柱状晶和等轴晶。Mo元素的加入使FeCoCrNiMo涂层中间区域枝晶尺寸显著增大，并呈现明显的取向特征。FeCoCrNiMo涂层在3.5 wt.% NaCl溶液中具有较高的腐蚀电位（-0.01）和较低的电流密度（0.94×10 A/cm），表现出优异的耐蚀性。腐蚀后的FeCoCrNiMo涂层上形成的钝化膜含有高含量的Cr和Mo的氧化物。Mo元素的加入增强了钝化膜的致密性和耐点蚀性。