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采用中温化学复合镀在高碳钢表面制备了Ni-Cu-P-TiN复合镀层,采用SEM、XRD对镀层的相组成与微观结构进行了分析,并研究了400℃热处理时间对镀层相组成、硬度、耐腐蚀性能的影响。结果表明,TiN相均匀的分散于Ni-Cu-P胞状结构的界面之间,沉积比例在4.5%~5.0%;在400℃下进行恒温热处理,随时间延长,Ni-Cu-P-TiN镀层中逐渐析出细小Ni3P相,截面硬度增加,40min时达到最高硬度960HV;随热处理时间继续延长,Ni3P相的晶粒粗化,镀层硬度下降;镀态Ni-Cu-P-TiN镀层的自腐蚀电流密度为7.92μA,仅为高碳钢(167μA)的1/20,经400℃下恒温热处理0~40min,其自腐蚀电流密度逐渐升高,40min时达到最大值28.2μA。
The phase composition and microstructure of Ni-Cu-P-TiN composite coating were prepared on the surface of high carbon steel by medium temperature chemical composite plating. The phase composition and microstructure of the coating were analyzed by SEM and XRD. The effects of heat treatment time at 400 ℃ on the phase composition, Hardness, corrosion resistance. The results show that the TiN phase is uniformly dispersed in the interface of Ni-Cu-P cellular structure with a deposition ratio of 4.5% -5.0%. The TiN phase is heat-treated at 400 ℃ with time prolonging. The Ni-Cu-P-TiN coating , The hardness of cross-section increased gradually and reached the maximum hardness of 960 HV at 40 min. With the prolongation of heat treatment time, the grain coarsening of Ni3P phase decreased the hardness of the coating. The self-corrosion current of Ni-Cu-P-TiN coating The density was 7.92μA, which was only 1/20 of that of high carbon steel (167μA). After being heated at 400 ℃ for 0-40min, the self-corrosion current density increased gradually to reach 28.2μA at 40min.