摘要
采用氨基磺酸体系电解液电沉积Co-Ni合金,研究了电解液中钴、镍金属离子浓度与合金镀层中钴含量的关系.利用扫描电子显微镜和X射线衍射分析测定了不同钴含量沉积层的微观形貌和晶体结构.同时研究了合金沉积层显微硬度和合金成份的关系及热处理的影响.实验结果表明:电解液中Co2+/(Co2++Ni2+)在0.1～0.5的范围内时,钴离子的优先共沉积的趋势最强.SEM观察结果和XRD分析测试表明,随着钴镍合金沉积层中钴含量的不断增加,低钴含量合金层粗大的颗粒状结晶逐渐转变为细致、均匀的三角形状结晶,最终又形成中等大小的颗粒状结晶.同时合金层中钴含量的逐渐增加,结构由fcc镍固溶体过渡为fcc的钴固溶体,最后转变为hcp的钴固溶体.并且在形成两个钴固溶体的钴含量范围内(20%～50%和60%～80%),所对应的钴镍合金层的硬度值远大于低钴含量区所具有fcc镍固溶体结构的合金层硬度.
Cobalt-mickal alloys were electrodeposited in a sulfamate bath containing various ratios of metallic additives. The relationship between the nickel content in the deposited layer and the ionic concentration of cobalt and nickel in the electrolyte were studied. The microscopic morphology and crystalline structure of the deposited layer with various Co contents were examined by using SEM and XRD techniques. The relationship between the microhardness and chemical composition as well as heat treatment procedures of the deposited layers was also investigated. The experimental results show that when the Co2+/(Co2++Ni2+) value of the electrolyte lies within 0.1～0.5,the Co ions have the strongest tendency to preferential codeposition. The SEM and XRD results show that with increasing the Co content in the deposited layer, the coarse gronular crystals of the low Co content layer transform into time-gramed and uniformly distributed triangular crystals and finally into granular crystals of medium sizes. In the meantime, the Co content in the deposited layer gradually increases, and its structure transforms from fcc Ni solid solution into fcc Co solid solution and at last into Co-solid solution. In the two regions of Co-solid solution(with Co content 20%～50% and 60%～80% respectively) the hardness of the Ni-Co layer is much larger than the hardness of the layer fcc Ni-solid solution with low Co contents.
出处
《材料科学与工艺》
EI
CAS
CSCD
2002年第4期419-423,共5页
Materials Science and Technology
