论文部分内容阅读
在改进的Watts槽中电沉积不同钴含量镍-钴合金涂层,采用电化学阻抗谱方法研究钴含量对涂层电沉积机理的影响。采用SEM和XRD表征涂层的表面形貌和晶体结构。采用维氏显微硬度和拉伸试验确定涂层的力学性能。结果表明,随着电解槽中Co~(2+)离子的增加,镍-钴涂层电荷转移电阻增加,相反Warburg阻抗降低。这可能是因为Co(OH)2阴极表面覆盖范围增大和金属离子向阳极表明扩散速率较高。而且,随着槽中钴含量的增加,合金涂层中的钴含量异常增加,(111)织构逐渐加强。当合金涂层的钴含量增加到45%时,晶粒尺寸减小,随之合金的硬度和强度增大。进一步增加钴含量达55%,合金的硬度和强度稍微降低。在Ni-25%Co涂层中能观察到最大的延展性,这是因为合金具有小晶粒尺寸和致密结构。
In the modified Watts cell electrodeposited cobalt-nickel alloy coating with different cobalt content, electrochemical impedance spectroscopy method to study cobalt content of the coating electrodeposition mechanism. The surface morphology and crystal structure of the coating were characterized by SEM and XRD. Vickers microhardness and tensile tests were used to determine the mechanical properties of the coatings. The results show that the charge transfer resistance of nickel-cobalt coating increases with the increase of Co 2+ in the electrolyzer, while the Warburg impedance decreases. This may be due to the increased surface coverage of the Co (OH) 2 cathode and the higher diffusion rate of metal ions toward the anode. Moreover, as the cobalt content in the cell increases, the cobalt content in the alloy coating increases abnormally and the (111) texture gradually increases. As the cobalt content of the alloy coating increases to 45%, the grain size decreases, and as the hardness and strength of the alloy increase. Further increase the cobalt content of 55%, the hardness and strength of the alloy slightly lower. Maximum ductility was observed in Ni-25% Co coatings because of the alloy’s small grain size and dense structure.