中文摘要：

研究了添加剂硫脲（TU）对低温碱性化学镀镍的镀速和镀层质量的影响。结果表明，随着硫脲加入量增大，化学镀镍速率先减小后增大，其适宜加入量为1mg／L；硫脲对H＋的还原具有抑制作用而对镀层组成影响很小。它的添加使镀层晶粒更为细致均匀，镀层更平滑，孔隙率更低；镀层以Ni为主并含少许Ni5P4，硫脲使Ni结晶峰得到增强。少量的硫脲会促进极化进而减缓镍的沉积，但加入量增加时，则增加去极化效应而加速镍的沉积。

英文摘要：

The influence of thiourea（TU） addition on the deposition rate and quality of coating was investigated for a low temperature alkaline electroless nickel plating process. The results show that the deposition rate firstly decreases and then increases with the increasing thiourea addition, while the suitable addition amount is 1 mg/L. Due to the thiourea addition, the grains of the coating are refined, and the coating becomes smooth and even, which may be ascribed to the inhibition of TU to the reduction of H＋. Thiourea has little influence on coating chemical composition. XRD results show that the coating consists of dominant Ni and a little NisP4. A small amount of thiourea may promote polarization, resulting in decline of plating rate, whereas depolarization occurs with the increasing addition, resulting in the rise of plating rate.