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酸性电解液中锌镍合金电沉积研究

时间:2017-03-21 20:47来源:毕业论文
论文通过选择合适的阳极及阳极电流控制方式,采用新的添加剂和络合剂实现了锌镍合金电镀。重点研究了酸性镀液中总离子浓度、阴极电流密度、镀液PH值、添加剂、镀液温度、镀液中

摘要:本论文通过选择合适的阳极及阳极电流控制方式,采用新的添加剂和络合剂实现了锌镍合金电镀。重点研究了酸性镀液中总离子浓度、阴极电流密度、镀液PH值、添加剂、镀液温度、镀液中镍锌含量比对锌镍合金镀层中含镍量的影响规律。采用x射线衍射仪、扫描电镜和多功能电子能谱仪等分析手段,对锌镍合金镀层的成分变化规律、微观形貌和结构、腐蚀产物、钝化膜的结构及成分进行了分析和研究。结果表明:(1)通过此新型的镀液配方和工艺条件,可获得含镍量为9%~12%,具有良好外观和耐蚀性的锌镍合金;(2)随镀层厚度的增加,锌的含量增加,镍的含量是先增加后减小,镀层中形成了镍的富积层;(3)含镍量不同,镀层的结构不同。当镀层中镍含量低于6%以下时,镍与锌形成固溶体组织η相;当镍含量为6%~10%时,还会有弥散的γ相合金存在;当镍含量为10%~14%时,镍与锌形成金属间隙化合物,其会相组织主要为γ相(Ni6Zn21),当镀层中镍含量高于25%时,镀层组织主要是α相,还会有弥散的ζ相(NiZn3)合金;(4)含镍14%以下的锌镍合金,其自腐蚀电位随镍含量的增加而增加;(5)锌镍合金镀层腐蚀产物主要是ZnO和ZnCl2•4Zn(OH)2,含有少量的2ZnCO3•3Zn(OH)2,腐蚀产物中没有镍的存在;(6)锌镍合金钝化膜表层主要由CrO3、Na2CrO4和H2O等组成;随钝化温度的升高,钝化膜的厚度增加;在锌镍合金钝化膜与镀层之间形成了富镍层。6714
关键词:锌镍合金  电镀合金  电沉积耐蚀性  合金钝化
The Research of Zinc - Nickel Alloy Electroplating in Acidic  Electrolyte
ABSTRACT:In this paper, electroplating Zinc-Nickel alloys has been realized by selecting appropriate anode and mode of controlling anode current and adopting new additive and complexant.The new process conditions and solutions of electroplating Zinc-Nickel alloys have been obtained and researched from all aspects.Focus on the influence of nickel content in Zinc-Nickel alloy in the total ion concentration, additives, cathodic current density,  PH , plating solution, temperature and the ratio of nickel and Zinc content in the plating solution in the acidic solution .The passivation of Zinc-Nickel alloys has been made from adopting Dew passivation solutions and good process,The metabolic rule of Zinc-Nickel alloy coatings components, microcosmic appearance and structure、corrosion production and the structure of passivation film and components have been analyzed and researched by means of adopting XRD, Glow Discharge Optical Emission Spectrometry,SEM and Multifuetional Electronic Energy Spectrum. The results show:(1)By the new process conditions and solutions of electroplating,the Zinc-Nickel alloys which the content of nickel is in 9 at% to 12 at%, has good appearance and high corrosion resistance has been obtained.(2)When the thickness of Zinc-Nickel alloys coatings increase,the content of zinc increase,but the content of nickel increase at the first some times and then decrease.There is an enrichment of nickel in the coatings.(3)Zinc-Nickel alloys electrodeposits exhibit different alloy phases as a function of their alloy composition.When the content of nickel is under 6 at%,alloys have η-phrase which is a solid solution of nickel in zinc.When the content of Nickel is 6 at%~9 at%,there is dispersion γ-phrase.Alloys of  l0~14% nickel are γ-phrase mainly.When the content of nickel exceeds 25 at%,ally have α-phrase mainly and have little ξ-phrase.(4) The stabilized potential of alloys that the content of Nickel is under 14%increase when the content of Nickel increased. The properties of corrosion resistance of passivation Zinc-Nickel alloys are much more than the properties of passivation Zinc coatings,passivation Cadmium comings and alloys of Cadmium-Titanium.(5)The corrosion productions are mainly ZnO and ZnCl2•4Zn(OH)2,have little 2ZnCO3•3Zn(OH)2 and isn't nickel.(6) The passivation films of Zinc-Nickel alloy ale mainly made up of CrO3、Na2CrO4 and H2O and there is a enrichment of nickel between the passivation films and alloy coatings. When the passivation temperature increase,the thickness of passivation films increase. 酸性电解液中锌镍合金电沉积研究:http://www.youerw.com/huaxue/lunwen_4361.html
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