等离子喷涂镍基合金涂层的组织与耐蚀性

Microstructure and Corrosion Properties of Plasma Arc Spraying Ni-based Coatings

采用等离子热喷涂技术在N80钢表面制备了镍基合金涂层,利用SEM/EDS和XRD以及电化学测试、盐雾试验等方法,对镍基合金涂层的微观组织和腐蚀性能进行了研究。结果表明:镍基合金涂层由单质Ni相及固溶体Cr1.2Ni2.88、FeNi3、MoO2和CuO组成。在5%NaCl溶液中,镍基合金涂层的腐蚀电流密度为1.2823×10-6 A/cm2,仅为N80钢的1/50。在饱和二氧化碳的地层水+3.5%NaCl溶液的酸性环境中,镍基合金涂层的腐蚀电流密度为1.074×10-6 A/cm2,仅为N80钢的1/25。在两种腐蚀环境条件下,镍基合金涂层的极化曲线均有明显的钝化趋势,具有良好的耐蚀性能。在盐雾腐蚀环境中,镍基合金涂层的腐蚀速率是N80钢的1/3,显著提高了基体的抗腐蚀性能。

Ni-based coatings were made on N80 steel by plasma arc spraying.The microstructure,chemical composition and the corrosion resistance of Ni-based alloy coatings were investigated by SEM/EDX,XRD,electrochemical and salt-fog test.The results showed that Ni-based alloy coatings constituted of Ni,Cr1.2Ni2.88,FeNi3,MoO2and CuO.In 5% NaCl solution,the corrosion current density of Ni-based alloy coatings was 1.2823×10-6 A/cm2,and only 1/50 of the N80 steel.In CO2saturated water and 3.5% NaCl solution,the corrosion current density of Ni-based alloy coatings was 1.074×10-6 A/cm2,and about 1/25 of the N80 steel.In the above two corrosion environment,the electrochemical polarization curves of Ni-based alloy coatings showed obvious passivation trend and the corrosion resistance of Ni-based alloy coatings was excellent.The salt-fog test displayed that the Ni-based alloy coatings exhibited better resistance than that of N80 steel,and the corrosion rate of Ni-based alloy coatings was about 1/3 of that of N80 steel.