Ni-Cr_2O_3复合等离子喷涂层热处理改性前后的结构及性能

Effect of Heat-Treatment on Microstructure and Corrosion Resistance of Plasma Sprayed Ni-Cr_2O_3 Composite Coating on 20 Steel Substrate

等离子喷涂层经热处理后可进一步改进其结构及性能,以往对其改性机理研究不多。采用等离子喷涂技术在20钢表面制备了Ni-Cr2O3复合涂层,经500℃、6 h热处理后随炉冷却。通过金相显微分析、X射线衍射、盐雾腐蚀、电化学试验等方法,对比研究了热处理前后Ni-Cr2O3复合涂层的组织形貌、相组成以及耐蚀性的变化。结果表明:Ni-Cr2O3复合涂层热处理前后物相组成未发生改变,经热处理后,孔隙率减小,组织更致密,耐蚀性大幅提高。

Ni-Cr2O3 composite coating was prepared on 20 steel substrate by plasma spraying.As-sprayed composite coating was heat treated at 500 ℃ for 6 h and then cooled in the oven.The microstructure and phase composition of the as-sprayed and heat-treated Ni-Cr2O3 composite coating were analyzed with a metallographic microscope and an X-ray diffractometer,and its corrosion resistance was evaluated with a salt-spray test rig and an electrochemical test rig.Furthermore,the effect of heat-treatment on the microstructure and corrosion resistance of the Ni-Cr2O3 composite coating was investigated.Results indicate that heat-treatment leads to no changes in the phase composition of plasma sprayed Ni-Cr2O3 composite coating.However,heat-treatment contributes to greatly reduce the porosity and refine the grains of the composite coating,leading to significantly improved corrosion resistance.