高频脉冲电镀镍镀层在3．5％NaCl溶液中的耐蚀性

Corrosion-resistance of high-frequency electroplated Ni in 3.5 % NaCl solution

研究了高频脉冲电镀Ni在3．5％NaCl溶液中的耐蚀性与频率的关系。通过腐蚀失重和阳极极化曲线测试表明，脉冲频率升高使镀层耐腐蚀能力增大，相比较直流电镀镀层，性能明显优异。通过SEM以及XRD测试观察其微观形貌及结构，结果表明，随着脉冲频率升高镀层表面更加平整，结晶粒径要小，明显优于直流镀层。电沉积时择优取向程度随着频率的升高也越来越大。在高频条件下，镍晶（111）型与（200）型的衍射强度之比可达0．05，镀层微晶尺寸可达48nm，达到纳米级。

Nickel coatings were pulse electro-deposited, the relationship of corrosion-resistance in 3.5% NaCl and the pulse frequency was studied. The weight loss tests and anode polarization curses show that the corrosion-resistance becomes much better as the pulse frequency rises, comparing to the DC Ni deposits, the corrosion-resistance of the pulse-electrodeposited Ni is obviously much better. Morphological and micro-structural information was acquired through investigations by techniques such as scanning electron microscopy （SEM）, X-ray diffraction （XRD）. The results indicate that the surface becomes much more level off, and the average grain size becomes more homogeneous and smaller when the pulse frequency rises, it is about 45nm, when the frequency is about 140kHz. The deposits have a highly preferred orientation of （200）, and the ratio of the diffraction intensity （I[111]/[200]） could be 0.045.