摘要
目的探究硫酸盐体系镀液中柠檬酸浓度、钨酸钠浓度及镀层热处理工艺,对镍钨合金镀层中钨含量、镀层硬度、镀层微观形貌和物相组成的影响。方法采用合金电沉积方法,以低碳钢为基体,在不同成分的镀液中制备了一定厚度的镍钨合金镀层,然后用不同的热处理工艺进行后处理。用扫描电镜(SEM)及其自带的EDS能谱观察镀层的微观形貌,检测镀层的钨含量。使用X射线衍射(XRD)分析镀层的物相组成、晶粒大小和晶格畸变情况。使用显微硬度计对合金镀层的硬度进行了测试。结果随着镀液中钨酸钠浓度的增大或者柠檬酸浓度的减小,镀层中的钨含量提高,晶粒尺寸减小,维氏硬度增大。热处理氛围对镀层硬度的影响不大,但会改变镀层微观形貌,镀层硬度随热处理温度先增大后减小,也随保温时间先增大后减小。结论当镀液中含有钨酸钠45 g/L,柠檬酸45 g/L,电镀完成后将镀层在400℃氩气保护下热处理1.5 h,得到的镀层是以镍为溶剂、钨为溶质的置换型固溶体Ni_(17)W_3,其具有表面平整、无裂纹,硬度达894HV0.1的优良性能。
The work aims to explore effects of citric acid concentration, sodium tungstate concentration in sulphate bath as well as plating heat treatment process on tungsten content in nickel tungsten alloy plating, plating hardness, plating microstruc-ture and phase composition. Ni-W alloy platings of certain thickness were prepared different bath composition on low carbon steel in alloy electrodeposition method. Later the platings were treated in different heat treatment processes. Microstructure of the platings was observed with scanning electron microscopy （SEM） , and tungsten content of the plating was detected by its built-in EDS energy spectrum. Phase composition, grain size and lattice distortion of the platings were analyzed by X-ray dif-fractometer （XRD）. Hardness of the alloy platings was tested with micro hardness tester. With the increase of sodium tungstate concentration or decrease of citric acid concentration in the bath, tungsten content in the plating increased, grain size decreased and Vickers hardness increased. Heat treatment atmosphere had little effect on hardness of the platings, but it could change mi-crostructure of the platings, hardness of the platings first increased and then decreased with the increase of heat treatment tem-perature and holding time. When the bath contains 45 g/L sodium tungstate and 45 g/L citric acid, the obtained plating is substi- tutional sosoloid Ni17W3 with Ni as solvent and W as solute. In this process, the plating is smooth and crack-free, and hardness of the plating is 894 HV0.1 after later heat treatment for 1.5 h under the protection of argon at 400℃ .
出处
《表面技术》
EI
CAS
CSCD
北大核心
2017年第7期85-90,共6页
Surface Technology
关键词
镍钨合金
电镀
热处理
硬度
晶格畸变
固溶体
nickel-tungsten alloy
electrodeposition
heat treatment
hardness
lattice distortion
sosoloid
