Effect of Temperature on the Immersion Gold Process Based on Electroless Ni-P Alloy Substrate

The immersion gold process based on electroless Ni-P alloy substrate with different P contents (4wt%, 9wt% and 1 1 wt%) was investigated by X-ray fluorescence spectrometer, atomic force microscopy and open circuit potential measurement and analysis. The effects of temperature on the gold deposition process were also discussed. The results show that the deposition rate, surface roughness and electrode potential are changed during the immersion gold process. At the same temperature, a higher P content often leads to a high electrode potential and a low initial deposition rate. However, the effect of temperature on immersion gold is relatively complex. In the range of 50 similar to 80 degrees C, increasing the temperature results in a positive potential and a better surface morphology of the gold coating with a smaller surface roughness, while a more negative potential and a bigger surface roughness are obtained at a higher temperature (90 degrees C).