激光熔覆FeCoCrNiMoBSi高熵合金涂层的电化学腐蚀行为

Electrochemical corrosion behavior of FeCoCrNiMoBSi high⁃entropy alloy coating prepared by laser cladding

研究了316L不锈钢基体表面制备的FeCoCrNiMoBSi高熵合金激光熔覆层的微观结构以及其在H_(2)SO_(4)溶液中的电化学腐蚀和浸泡腐蚀性能。激光熔覆制备的高熵合金涂层呈现双层结构,包括底部的柱状晶和顶部的等轴晶。在0.3 mol/L的H_(2)SO_(4)溶液中,高熵合金涂层的自腐蚀电位为0.091 V,自腐蚀电流密度为11.499μA/cm^(2),极化阻抗为9839.90Ω,分别为316L不锈钢的2.12倍、6.17%和12.2倍,高熵合金涂层表现出更大的容抗弧半径和阻抗模值。此外,在浓度为50%的H_(2)SO_(4)溶液中,高熵合金涂层的腐蚀速率较低,约为0.098 mg/(dm^(2)·d);316L不锈钢基体表现出明显的非均匀腐蚀,而高熵合金涂层腐蚀表面整体平坦,具有均匀的腐蚀速率。综合结果显示,FeCoCrNiMoBSi高熵合金激光熔覆层的耐腐蚀性能明显优于316L不锈钢基体。

FeCoCrNiMoBSi high⁃entropy alloy(HEA)coating was fabricated on the 316L stainless steel substrate via laser cladding.The microstructure,electrochemical corrosion and immersion corrosion properties of the HEA coating in H_(2)SO_(4) solution were investigated.The results show that the laser clad HEA coating exhibits a bilayer structure,consisting of a columnar crystal at the bottom and an equiaxed crystal at the top.In the 0.3 mol/L H_(2)SO_(4) solution,the self⁃corrosion potential,self⁃corrosion current density and polarization resistance of the HEA coating are 0.091 V,11.499μA/cm^(2) and 9839.90Ω,which are 2.12 times,6.17%and 12.2 times,respectively,of the 316L stainless steel substrate.The HEA coating exhibits larger capacitance arc radius and impedance modulus value.Additionally,in the 50%H_(2)SO_(4) solution,the corrosion rate of the HEA coating is lower,approximately 0.098 mg/(dm^(2)·d),316L stainless steel substrate shows conspicuous heterogeneous corrosion,whereas the corrosion surface of the HEA coating remains uniformly flat,showing homogeneous corrosion rate.The comprehensive results show that the corrosion resistance of the FeCoCrNiMoBSi high⁃entropy alloy coating on the 316L stainless steel substrate is significantly better than that of the substrate itself.