不同络合剂对化学镀镍过程的影响

The Effect of Complexing Agents on the Processing of Electroless Nickel Plating

  • 摘要: 用热力学平衡的方法研究了在BaTiO3系陶瓷PTCR上进行化学沉积金属镍电极时常用的醋酸盐-镍离子、甘氨酸-镍离子和柠檬酸盐-镍离子体系化学镀镍溶液中各种型体镍离子的分布。研究结果表明,加入络合剂会影响化学镀镍的速度,醋酸盐会使化学沉积速度升高,而甘氨酸和柠檬酸盐会使化学镀镍速度明显下降,这可能和混合电位及空间位阻、化学键合力等因素有关。选择合适的络合剂对于化学镀镍的稳定操作有着十分重要的意义。

     

    Abstract: Based on thermodynamic speciation calculations, the roles of complexing agents in electroless nickel solutions, employed in ohemic electrodes formation of BaTiO3-based PTCR ceramics, were investigated in this paper. Electroless nickel solutions, using acetate or citrate or glycine, decrease the concentration of free nickel. All solutions exhibit a fraction of free nickel, which would be decreased with the formation constant of the nickel-ligand species increased. The plating rate and solution stability are dependent upon the structure of nickel in solution. Higher deposition rates were observed in nickel solutions with fewer chelated sites in the nickel complex.

     

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