激光重熔合成AlCo_(x)CrFeNiCu高熵合金涂层组织与耐腐蚀性能

为了提高机械零部件的腐蚀性能,采用冷喷涂辅助激光重熔合成不同Co含量AlCo_(x)CrFeNiCu(x=0、0.5、1、1.5、2)高熵合金涂层。通过XRD、SEM、EDS、TEM、电化学测试系统等设备检测分析了Co含量的变化对合金涂层相结构、显微组织、耐腐蚀性能的影响。结果表明,激光重熔合成AlCo_(x)CrFeNiCu高熵合金涂层是由简单的BCC和FCC相构成,当x=1时高熵合金涂层的晶格畸变最大,随着Co含量的增加,激光重熔合成AlCo_(x)CrFeNiCu高熵合金涂层的等轴树枝晶由少变多并逐渐细化,柱状树枝晶的间距先增大后减小。在3.5%NaCl腐蚀介质中,当x=0.5时高熵合金涂层中Cu元素轻微偏析,有少量点蚀发生,AlCo_(0.5)CrFeNiCu高熵合金涂层自腐蚀电位最正,腐蚀电流密度达到最小,腐蚀速率2.28×10^(-3)mm/a,表现出良好耐腐蚀性。

Microstructure and corrosion resistance of AlCoxCrFeNiCuHEA coatings synthesized by laser remelting

To improve the corrosion resistance of mechanical components, Cold sprayed assisted laser remelting was used to synthesized HEA coatings with different Co contents AlCoxCrFeNiCu (x = 0, 0.5, 1, 1.5, 2). The effect of the change in Co content on the phase structure, microstructure and corrosion resistance of the alloy coating was analysed by XRD, SEM, EDS, TEM, electrochemical test system and other equipment tests. The results show that the laser remelting AlCoxCrFeNiCu HEA coatings is composed of simple BCC and FCC phases, with the increase of Co content, the equiaxed dendrites of the laser remelted AlCoxCrFeNiCu HEA coatings become less and more and gradually refine, and the spacing of columnar dendrites first increases and then decreases. In 3.5% wt. NaCl corrosive medium, the laser remelting synthesized AlCo0.5CrFeNiCu HEA coatings has the most positive self-corrosion potential, the corrosion current density reaches the minimum, the corrosion rate is 2.28x10-3(mm/a), the AlCo0.5CrFeNiCu HEA coatings shows good corrosion resistance.