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目的 提高镁合金表面Ni-P-SiC复合镀层的耐腐蚀性能和耐磨性能.方法 采用加入SiC微粒的Ni-P化学镀溶液,在AZ91D镁合金表面制备Ni-P-SiC复合镀层,并在不同温度下进行热处理,通过X射线衍射(XRD)、显微硬度测试、电化学腐蚀测试和摩擦磨损实验等方法分析和评价镀层的组织构成、显微硬度、耐腐蚀性能和耐磨性能.结果 Ni-P-SiC复合镀层经320℃热处理后,组织结构由非晶向晶体转变,并伴随有Ni3P相的析出.此温度下热处理的Ni-P-SiC复合镀层:显微硬度最高,可达1120HV,为未热处理时显微硬度(620HV)的1.81倍;自腐蚀电位为-0.697 V,较未热处理样品的(-0.727V)有所提高;腐蚀电流密度基本最小,为0.984 μA/cm-2;磨损体积最小,为0.324×10-3mm3.340℃热处理的复合镀层则磨损体积最大,为1.43×10-3mm3.结论 在AZ91D镁合金表面制备的Ni-P-SiC复合镀层经过320℃热处理保温1h后,复合镀层的硬度、耐腐蚀性能和耐磨性能均有所提高.

The work aims to improve the wear resistance and corrosion resistance of Ni-P-SiC composite coating on the surface of magnesium alloys.Ni-P electroless plating solution with SiC particles was used to prepare Ni-P-SiC composite coating on the surface of AZ91D Mg alloy,and the composite coating was heat treated at different temperature.Then the microstructure,micro-hardness,wear resistance and corrosion resistance of the composite coating were analyzed and evaluated by virtue of XRD,micro-hardness test,electrochemical corrosion test and friction-wear test.After thermally treated at 320 ℃,the microstructure of Ni-P-SiC composite coating transformed from amorphous into crystal microstructure accompanied with precipitation of Ni3P phase.Micro-hardness of the Ni-P-SiC composite coating subject to heat treatment at the temperature was up to 1120HV,1.81 times higher than that of the coating not subject to heat treatment (620HV);Ecorr of the Ni-P-SiC composite coating was-0.697 V,higher than that of the coating not subject to heat treatment (-0.727 V);value of Jcorr was the lowest (0.984 μA/cm 2),and wear volume of Ni-P-SiC composite coating was the lowest as well (0.324× 10-3/rnrn3).When the heat treatment temperature was 340 ℃,the wear volume of Ni-P-SiC composite coating was up to 1.43× 10-3/mm3.After being heat treated at 320 ℃ for 1h,micro-hardness,corrosion resistance and wear resistance of the Ni-P-SiC composite coating prepared on the surface ofAZ91D Mg alloy are all increased.