脉冲电流密度对Ni-SiC镀层微观结构和显微硬度的影响

Effect of current density on microstructure and microhardness of Ni-SiC coatings

采用脉冲电沉积方法,在压缩机阀片表面制备Ni-SiC镀层。利用原子吸收分光光度计、透射电镜和硬度计研究脉冲电流密度对Ni-SiC镀层SiC粒子复合量、微观结构和显微硬度的影响。结果表明,随着脉冲电流密度的增大,Ni-SiC镀层SiC粒子的复合量先增加后略有降低。在脉冲电流密度为7A/dm2时,镀层SiC粒子的复合量高达9.92%(质量分数)。脉冲电流密度为7A/dm2时,镀层致密、晶粒细小,SiC粒子均匀分布于镀层中,且团聚现象较少。当脉冲电流密度为7A/dm2时,镀层的显微硬度高达842.9Hv。

Ni-SiC coatings were synthesized on the surface of compressor valves by using pulse electrodeposition method.The effect of current density on the content,microstructure and microhardness of the coatings was in-vestigated by using the atomic absorption spectrophotometer,transmission electron microscope and microhard-ness tester.The results show that the SiC particle content in the coating increases first and then decreases with the increase of pulse current density.The current density was 7 A/dm2 ,the coating has a density and fine structure,and SiC particles are evenly distributed in this coating.The current density was 7 A/dm2 ,the micro-hardness of the coating reaches 842.9 Hv.