【作者】 郭莉华；

【导师】 熊金平； 赵景茂；

【作者基本信息】 北京化工大学 ， 应用化学， 2003， 硕士

【摘要】 本文在几种典型溶液配方的基础上,采用250毫升的霍尔槽实验,阳极为纯锌板,通过小槽电镀实验以及镀液性能、镀层性能测试,最后分析对比确定出最佳溶液成分及工艺条件。研究了主盐含量、添加剂、电流密度、温度及pH值对镀层镍含量的影响。初步研究了锌镍合金镀层组成、结构与镀层的氢脆性能、耐蚀性能的关系。开发研究了添加剂B,使得含有添加剂B的氯化物体系得到的镀层能满足低氢脆和高耐蚀性的性能要求。用双电解池渗氢实验和缺口延迟破坏实验共同验证了镀层的氢脆性能。电化学渗透方法能够实地监控和评价镀层的氢脆性能。最大渗氢电流Jm和衰减曲线斜率K可以用来表示电镀层的有关性能,如镀层中的氢浓度和孔隙率等。添加剂B能够改善镀层的氢脆性能,但是添加剂含量增加,镀层中镍含量减少,因此添加剂的含量应适量。操作温度为30℃、电流密度为2A/dm2时, 含有添加剂B的氯化物体系得到的镀层镍含量为13%左右,镀层外观细致均匀,与基体结合力强,并且耐蚀性能良好,氢脆性能符合ASTM标准。镍含量为13%左右的锌镍合金镀层仅有单一的γ相出现,其组成为金属间化合物Ni5Zn21,镍的存在有利于抑制Zn(OH)2向ZnO转化,<WP=4>同时,镀层的组织结构呈现网状微裂纹,这些都增加了镀层的耐腐蚀性能。镀层氢脆机理倾向于氢与位错交互作用。锌镍合金共沉积机理倾向于氢氧化物抑制机理,即异常共沉积。更多还原

【Abstract】 The electrodeposition of a metallic coating on to high strength steel introduces the possibility that the steel fail by hydrogen embrittlement. This paper describes a fundamental study of the hydrogen uptake resulting from electroplating with zinc-nickel alloy in chloride electrolyte. The influence of various of parameters for example the solution temperature, PH and cathode current density on the nickel content in the electrodeposited zinc-nickel alloy coating have been investigated. Properties of the Zn-Ni alloy deposit were determined with the methods of the notch tensile and the neutral salt spray. And the satisfactory alloy deposit can be obtained at 30℃ and cathode current density 2A/dm2 from the chloride bath.Evaluated of hydrogen uptake and permeation in Zinc-Nickel alloy and metals by an electrochemical technique. Zinc-nickel alloys have been obtained from two electroplating baths, which present a low hydrogen <WP=6>embrittling. And the results were tested by the notched tensile test.Determining the presence of escape channels as well as other microstructural features enables one to control plating processes to assure the production of articles that exhibit low hydrogen embrittlement.The predominant phase found in the deposit was gamma-Ni5Zn21 phase. The microstructure of cross-sections of the deposits could improve the corrosion resistance of the alloy.In the deposition of Zn-Ni alloy, the predominant presence of Zinc is result of anomalous codeposition.更多还原