采用激光熔覆工艺在Q235钢表面制备了Al2CrFeCoCuNixTi高熵合金涂层, 分析了Al2CrFeCoCuNixTi高熵合金涂层的组织结构, 测试了Al2CrFeCoCuNixTi高熵合金涂层在0.5 mol/L HNO3溶液及0.5 mol/L HCl溶液中的耐蚀性能。结果表明: Al2CrFeCoCuNixTi高熵合金涂层主要分为熔覆区、结合区、热影响区, 熔覆区组织主要由等轴晶组成, 等轴晶上分布有微米尺度的粒子; 合金相结构简单, 由体心立方(BCC)及面心立方(FCC)结构组成; Cr元素和Ni元素的钝化作用及由Al元素形成Al2O3或Al2O3·H2O膜使得Al2CrFeCoCuNixTi高熵合金涂层在0.5 mol/L HNO3溶液及0.5 mol/L HCl溶液中具有较好的耐蚀性能, 自腐蚀电流密度与基体Q235钢相比降低一两个数量级; 0.5 mol/L HCl溶液中的Cl-会穿透Ni0.5高熵合金涂层表面形成的钝化膜, 出现轻微小孔腐蚀。

The Al2CrFeCoCuNixTi high entropy alloy coating was prepared by laser cladding on Q235 steel surface. The microstructure of Al2CrFeCoCuNixTi high entropy alloy coatings were analyzed, and the corrosion resistance of Al2CrFeCoCuNixTi high entropy alloy coatings in 0.5 mol/L HNO3 solution and 0.5 mol/L HCl solution were tested. The experimental results show that the Al2CrFeCoCuNixTi high entropy alloy coating can be divided into cladding zone, bonding zone and heat affected zone. The microstructure of cladding zone is mainly composed of equiaxed grain, with micron-grade particles distributed on it, the phase structure of Ni1.0 high entropy alloy coating was simple for FCC and BCC structure. Due to the passivation effect of Cr and Ni elements and formation of Al2O3 and Al2O3·H2O films by Al element, the Al2CrFeCoCuNixTi high entropy alloy coating exhibits good corrosion resistance in 0.5 mol/L HNO3 solution and 0.5 mol/L HCl solution. Compared with Q235 steel, the corrosion current density decreases 1-2 orders of magnitude. Pitting corrosion appears because of Cl- in 0.5 mol/L HCl solution can penetrate the passive film on the Ni0.5 high entropy alloy coating surface.