钨含量对Ni-W合金镀层结构及耐蚀性能的影响  

Effect of W Content on the Structure and Corrosion Resistance of Ni-W Alloy Plates

作　　者：龚睿[1] 柳林[1] 

机构地区：[1]华中科技大学材料成型及模具技术国家重点实验室,湖北武汉430074

出　　处：《稀有金属材料与工程》2008年第1期130-134,共5页Rare Metal Materials and Engineering

摘　　要：以硫酸镍及钨酸钠为主盐,采用电沉积法在Cu基体上制得了Ni-W合金镀层。通过X射线衍射分析、X射线荧光探针、金相显微镜、显微硬度计和电化学等测试手段研究了合金镀层的组织结构、表面形貌、力学性能及在3%NaCl溶液中的耐蚀性能。结果表明,镀层结构和性能与镀层中的W含量密切相关。当W含量>21%(原子分数,下同)时,镀层为非晶态结构;当W含量<21%时,镀层为晶态结构;且当W含量在20%左右时,镀层为柱状晶结构。硬度测试结果表明,Ni-W柱状晶镀层及非晶态镀层的维氏硬度HV0.1均达到了5800MPa以上;两镀层光滑平整,与基体结合紧密。动电位极化测试结果表明:2种镀层在3%NaCl溶液中均存在自钝化现象,并形成较宽的稳定钝化区,钝化区间宽度远优于1Cr18Ni9Ti不锈钢,且发生均匀腐蚀,表现出良好的耐蚀性。并且,随着W含量的增加,镀层的硬度和耐蚀性不断提高。The Ni-W alloy plates were prepared by electro-deposition on copper substrate using nickel sulphate and sodium tungstate as precursors. The structure and morphology of the electrodeposited plates as well as microhardness were investigated by X-ray diffraction（XRD）, X-ray fluorescence system （XRF）, optical microscopy （OM） and micro-indentation. It is found that the structure and hardness of the plates are closely related to W content. The plates are of crystalline structure when W content is less than 21 at%, but of amorphous structure when W above the value. Especially, the plate exhibits a columnar crystalline structure when W content is around 20 at%. The microhardness increases continuously with the increase of W content. Both columnar and amorphous plates grew well on the copper substrate and exhibited a high hardness of above HV 5800 MPa. Finally, the corrosion resistance of the Ni-W plates with different W contents was examined by electrochemical polarization in a 3% NaCl solution open to air. It is found that the columnar and amorphous plates also displayed excellent corrosion resistance as indicated by a wider passive region and a lower corrosion current density as compared with 1Cr18Ni9T stainless steel.

关 键 词：电沉积 NI-W合金 W含量 结构 耐蚀性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理]