摘要
研究了在AZ31B镁合金表面以硫酸镍和碱式碳酸镍为主盐镀液体系化学镀Ni-P。通过扫描电镜(SEM)、能谱分析(EDX)、X射线衍射(XRD)及动电位极化曲线分析,探讨了2种不同镀层的组织形貌、物相成分及耐蚀性。结果表明:两种不同镍盐体系均能得到致密、均匀、无缺陷的Ni-P镀层;磷的含量相近,质量分数分别为6.67%,6.60%,属于中磷镀层;镀层的腐蚀电位分别为-0.24,-0.37V(vsSCE)。比较两种镀层发现,以硫酸镍为主盐体系得到的镀层晶胞更细小,均匀、致密;镀层腐蚀电位正移了0.1V,钝化区间更为明显,耐蚀性能更为优异。
NiSO4 and NiCO3·2Ni(OH)2·4H2O were separately used as the main salts to prepare electroless Ni-P alloy coating on the surface of AZ31B magnesium alloy.The microstructure,phase composition,and corrosion resistance of the coatings were analyzed by means of scanning electron microscopy,energy dispersive spectrometry,and X-ray diffraction,while the corrosion resistance of the coatings was evaluated by measurement of polarization curves.Results showed that compact,uniform,and defect-free amorphous Ni-P coating could be prepared on the surface of AZ31B Mg alloy surface from the bath containing NiSO4 or NiCO3·2Ni(OH)2·4H2O as the main nickel salt.The resulting Ni-P coatings had similar mass fraction of P,i.e.,6.67% and 6.60%,respectively.Moreover,the Ni-P alloy coatings prepared from nickel sulfate bath and basic nickel sulfate bath recorded a corrosion potential of-0.24 V(SCE)and-0.37 V(SCE),respectively.Besides,the Ni-P coating deposited from the nickel sulfate bath was more uniform and compact and composed of smaller grains,while its corrosion potential moved forward by 0.1 V(SCE),showing an extended passivation range and better corrosion resistance.
出处
《材料保护》
CAS
CSCD
北大核心
2008年第7期23-25,共3页
Materials Protection
