铝材化学镀Ni-W-P溶液中硝酸镧含量对镀层性能的影响  

Influence of La( NO_3)_3 Content on Corrosion Resistance of Electroless Ni-W-P Alloy Coating on Aluminum Substrate

作　　者：余祖孝[1] 郝世雄[1] 李兰[2] 郑德韬 

机构地区：[1]四川理工学院材料与化学工程学院材料腐蚀与防护四川省重点实验室,四川自贡643000 [2]宜宾学院实验与教学资源管理中心,四川宜宾644007

出　　处：《材料保护》2015年第5期24-26,38,共4页Materials Protection

基　　金：材料腐蚀与防护四川省重点实验室基金(2014CL20);四川理工学院人才引进项目(2012RC04)资助

摘　　要：为了提高铝材Ni-W-P镀层的耐腐蚀性，在镀液中加入La（NO3）3，在1060铝表面化学镀Ni—W—P合金层。采用电化学法和失重法分析了合金镀层的耐蚀性，采用扫描电镜观察合金镀层的形貌，采用X射线衍射仪分析了镀层的结构；研究了La（NO3）3含量对Ni—W-P镀层沉积速率、孔隙率、腐蚀速率、腐蚀电位、腐蚀电流、交流阻抗、维氏硬度等性能的影响；对镀层进行热处理，研究了热处理对合金镀层性能的影响。结果表明：当镀液中La（NO3）3质量分数为1．0％时，所得镀层的沉积速率最大，为65．7g/（m^2·h），维氏硬度最高，为80．3HV，孔隙率最低，镀层的耐蚀性能最好，镀层包状物颗粒大小均匀、紧密、无缺陷；经100～500℃热处理后，镀层硬度有所提高，但耐蚀性有不同程度下降，经300℃热处理后，合金维氏硬度高达136HV，是未热处理的1．7倍。La( NO3)3was introduced into the electroless Ni-W-P plating bath so as to prepare Ni-W-P alloy coatings with improved corrosion resistance on 1060 Al substrate. The morphology and phase structure of as-plated alloy coating were analyzed by scanning electron microscopy and X-ray diffraction,and its corrosion resistance was evaluated by electrochemical method and mass loss method. Furthermore,the effects of heat treatment and content of La( NO3)3in the plating bath on the deposition rate,porosity,corrosion rate, corrosion potential, corrosion current, electrochemical impedance spectrum and Webster hardness of the Ni-W-P alloy coating were investigated. Results showed that,when La( NO3)3additive was added into the plating solution at a mass fraction of 1. 0%,the maximum deposition rate [65. 7g /( m2·h) ]and Webster hardness( 80. 3 HV),as well as the lowest porosity and best corrosion resistance of electroless Ni-W-P alloy coating were obtained; and relevant alloy coating consisted of dense grains with uniform size and without defects. After heat treatment at 100 ~ 500 ℃,the hardness of the alloy coating was increased to some extent,but its corrosion resistance was reduced at a certain degree. Particularly,the Ni-W-P alloy coating heat-treated at 300 ℃ exhibited the highest Webster hardness of 136HV( it was 1. 7 times as much as that of the as-plated alloy coating).

关 键 词：化学镀 Ni—W—P合金 1060铝 La(NO3)3 耐蚀性 热处理 

分 类 号：TB306[一般工业技术—材料科学与工程]