硫酸盐电铸镍内应力的影响因素

研究了NiSO4·6H2O质量浓度、NiCl2·6H2O质量浓度、温度和阴极电流密度等工艺参数对硫酸盐电铸镍层内应力的影响。通过铜箔阴极弯曲法半定量地测定了镍铸层的内应力,采用扫描电镜和X射线衍射表征了镀层在不同应力状态下的表面形貌和微观结构。结果表明,当NiSO4·6H2O质量浓度为100～150g/L时,其变化对内应力影响较大;镀液中氯离子浓度的增加会增大镀层内应力;低温和大电流密度条件下获得的镀层具有大的拉应力,高温小电流则有利于降低镀层的拉应力。

Factors affecting internal stress of electroformed nickel in sulfate bath

The effect of process parameters such as nickel sulfate concentration, chlorine ion concentration, temperature and cathodic current density on the internal stress of electroformed nickel in sulfate bath was studied. The internal stress was measured semi-quantitatively by copper cathodic curvature method. The surface morphology and micro-structure of the nickel deposit under various stress state were characterized by scanning electron microscopy and X-ray diffraction. The results showed that the internal stress is sensitive to the change of the concentration of nickel sulfate within the range of 100 ～ 150 g/L and is increased with the increase of chloride ion concentration in electrolyte. Low temperature or high current density favors the tensile stress of nickel deposit, while high temperature or low current density favors compressive stress.