沉积时间对AZ91D合金表面Ni-P-SiC复合镀层性能的影响

目的提高镁合金的耐蚀性和耐磨性。方法以AZ91D镁合金为基体,采用SiC颗粒质量浓度为3 g/L的Ni-P化学镀溶液,在其表面沉积不同时间,制备Ni-P-SiC复合镀层。通过扫描电子显微镜(SEM)、显微硬度测试、粗糙度仪、电化学腐蚀和磨损等试验来分析和评价Ni-P-SiC复合镀层的厚度、表面粗糙度、显微硬度、耐腐蚀性能和耐磨性能。结果 Ni-P-SiC复合镀层的厚度和表面粗糙度随沉积时间增加而增加,沉积时间为150 min时,镀层厚度可达53μm,表面粗糙度为2.5μm。沉积时间为120 min时,镀层的显微硬度最高,为641HV,此时复合镀层的耐蚀性和耐磨性最好,自腐蚀电位高达-0.73 V,腐蚀电流密度为0.78μA/cm~2,磨损体积最小,为1.04×10~(-3)mm~3。与AZ91D镁合金基体相比,沉积复合镀层后的样品更耐蚀,说明复合镀层有效改善了镁合金基体的耐蚀性。结论沉积时间对Ni-P-SiC复合镀层的性能有一定影响,在沉积时间为120 min时获得的复合镀层具有较好的耐蚀性和耐磨性。

Effect of Deposition Time on Properties of Ni-P-SiC Composite Coating on AZ91D Alloy

The work aims to enhance corrosion and wear resistance of magnesium alloys. Ni-P-SiC composite coating was prepared by depositing AZ91D magnesium alloy in Ni-P electroless plating solution with 3 g/L SiC particle for different deposi-tion time. Thickness, surface roughness, microhardness, wear and corrosion resistance of Ni-P-SiC composite coating were ana-lyzed and evaluated with SEM, roughmeter, electrochemical corrosion and wear tests. The thickness and surface roughness of Ni-P-SiC composite coating increased as deposition time increased. When the deposition time was 150 min, the thickness and roughness were 53μm and 2.5μm, respectively; when the deposition time was 120 min, the maximum microhardness was 641HV, corrosion and wear resistance were the best,Ecor,Jcor and wear volume were?0.73 V, 0.78 μA/cm2 and 1.04×10?3 mm3, respectively. Compared with the AZ91D magnesium alloy, the sample produced after deposition exhibited better corrosion re-sistance after deposition, indicating that the Ni-P-SiC composite coating has improved corrosion resistance of the Mg alloy ef-fectively. The properties of Ni-P-SiC composite coating are significantly influenced by deposition time. And the composite coating obtained at the deposition time of 120 min has better corrosion and wear resistance.