The porosity of gold plating by dust contamination

The porosity of electric contacts caused by dust contamination during gold plating was much more serious than that caused by simply a roughness of the substrate. Nevertheless, experimental results showed that even when plating on a dusty substrate, porosity was still closely related to the substrate roughness. Dust contamination on rougher substrates produced larger numbers of pores. Pores caused during gold plating were inspected by both scanning electron microscopy and X-ray energy spectrometry. Silicon and aluminium, as well as other elements of dust particles found in the pores, showed the existence of dust contamination on the substrate. Various chemical and ultrasonic cleaning methods were tested in an attempt to improve the plating quality and to reduce pore formation at the contacts. It was found that ultrasonic cleaning in acetone for more than 20 minutes is necessary for reducing porosity and increasing the sliding duration.<>