Study on Electroless Tin Coating on the Surface of Red Copper

Abstract

In order to meet the demand for tin-rich treatment in the decoration industry, electroless tin plating experiment was carried out on the surface of red copper. The thickness of the tin coating ranged from 0.15 to 0.76 μm as the deposition time varied from 5 to 40 min. Scanning electron microscope (SEM) was used to analyze the microstructure of the tin coating. X-ray fluorescence spectrometer (XRF) was used to analyze the thickness of the coating. The chemical elements of the coating were investigated using energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of the tin coating was compared using an electrochemical workstation, which measured the electrochemical impedance spectroscopy (EIS) and Tafel polarization curves of tin coatings. Results showed that as the deposition time prolonged, the Sn content on the surface of the tin coating continuously rose, leading to a thicker coating. The surface of the tin coating was composed of a large amount of SnO2 and a small amount of metallic Sn. The deposition time was found to have a certain impact on the microstructure and corrosion resistance of the tin coating. As the deposition time was extended from 5 to 40 min, the microstructure of the tin coating underwent changes, and its corrosion resistance progressively deteriorated. Corrosion resistance was lowest at 20 min, showing slight improvement at 40 min compared to 20 min.

Keywords

• electroless tin plating|deposition time|surface properties|corrosion resistance