热处理对ZL102合金化学镀Ni-P-SiC镀层结构与性能的影响

Influence of heat-treatment on structure and properties of electroless Ni-P-SiC coating on ZL102 alloy

采用直接化学复合镀法在ZL102合金表面制备了Ni-P-SiC复合镀层,经不同温度热处理后,利用XRD、DSC、扫描电镜等对复合镀层的结构和形貌进行了分析,并对镀层的结合力、显微硬度、耐蚀性及耐磨性等进行了测试。结果表明:镀态镀层由晶态相和非晶态相组成,热处理过程中非晶态相向晶态转化;镀层的显微硬度随热处理温度的升高呈先升后降的趋势,在400℃时达到最大值1395.28 HV;镀层经400℃×1 h热处理后,镀层中的镍和磷原子向铝基体中扩散,复合镀层与基体结合良好,耐磨性和耐蚀性较基体有很大程度的改善,但热处理后镀层的耐蚀性与镀态的相比有所降低。

Ni-P-SiC composite coating on the surface of ZL102 alloy was prepared by direct electroless.After heat treatment at different temperature,the structure and the morphology of the coating were analyzed by XRD,DSC and SEM,and the bonding strength,hardness,corrosion resistance and wear resistance of the coatings were tested too.The results show that the coating consists of an amorphous phase coexisting with a crystalline phase.The amorphous phase is crystallized into crystalline phase during heat treatment.The microhardness of the deposit increases with the increase of heat treatment temperature below 400 ℃,after it decreases,and the microhardness can reach1395.28 HV at 400 ℃.After heat treatment at 400 ℃ for 1 h,the inter-diffusion between the deposits and substrates is mainly the diffusion of Ni and P into aluminum alloy.The composite coating has high bonding strength and the corrosion resistance and wear resistance of the substrate are considerably improved.However,the coating has more corrosion resistance than that of the heat treatment coating.