Ni/SiC复合镀层腐蚀行为研究  

Corrosion Behavior of Electroplated Ni/SiC Composite Coating in Saline Solution

作　　者：郑学斌[1] 谭澄宇[1] 赵旭山[1] 刘宇[1] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083

出　　处：《材料保护》2008年第2期17-19,共3页Materials Protection

摘　　要：研究了Ni/SiC复合镀层在3.5%NaCl溶液中的腐蚀行为。测定了Ni/SiC镀层在NaCl溶液中的失重曲线,利用Solartron恒电位仪测定其极化曲线,借助扫描电镜对镀层表面形貌进行了观察。结果表明,随着腐蚀时间的延长,腐蚀失重逐渐增加,但腐蚀速率逐渐降低;Ni/SiC复合镀层与纯Ni镀层耐盐水腐蚀能力基本相当;Ni/SiC复合镀层在3.5%NaCl溶液中的开路电位要高于纯Ni镀层的开路电位;在3.5%NaCl+H2O2溶液中,两种镀层的开路电位均明显正移,且Ni/SiC复合镀层自腐蚀电流降低,说明复合镀层耐盐水腐蚀能力有所提高。镀Ni层中引入SiC颗粒能使其组织细化,并促进复合镀层在3.5%NaCl溶液中发生钝化,可能是Ni/SiC镀层在盐水中耐蚀性能提高的主要原因。The corrosion behavior of electroplated Ni/SiC composite coating in 3.5% NaCl solution was evaluated.Thus the weight loss curve of Ni/SiC coating in 3.5% NaCl solution was measured,and its polarization curve was measured using a Solartron potentiostat device.Besides,the morphology of the e-lectroplated Ni/SiC composite coating was observed using a scanning electron microscopy(SEM)and compared with that of electroplated Ni coating.Results showed that the weight loss of the Ni/SiC composite coating increased and its corrosion rate gradually decreased with increasing immersion time.The Ni/SiC composite coating had corrosion resistance comparable to that of Ni coating in the saline solution,and the former had a more positive open circuit potential than the latter.Moreover,the open circuit potentials of the two types of electroplated Ni-matrix coatings shifted positively,and the Ni/SiC composite coating recorded a lower corrosion current in 3.5% NaCl+H2O2 solution,indicating that the composite coating had better corrosion resistance.It was supposed that the introduction of SiC contributed to refining the e-lectroplated Ni-matrix coating and enhancing its passivation in the saline solution as well,and hence increasing its corrosion resistance therein.As main factors that the composite coatings containing SiC grains were fine electronickelling microstructures and easy to be passivation in the solution.

关 键 词：Ni/SiC复合镀层 极化曲线 NACL溶液 腐蚀行为 

分 类 号：TG172[金属学及工艺—金属表面处理]