Effect of polarization scan rate on the corrosion properties of SAC305 in acidic solution

Abstract

The corrosion behaviour of the Sn-3.0Ag-0.5Cu (SAC305) solder to the corrosion properties of alloys in an acidic solution were investigated under polarized conditions. The corrosion parameters including the current potential and corrosion current of solder were determined through different scan rates. The potentiodynamic polarisation test was used to study the corrosion properties of SAC305 solder through polarization curves. Initially, SAC305 solder was punched into a pellet shape. Then, the soldering process was performed in order to let the solder connected to the copper wire. The solder were grinded and mounted using epoxy resin and hardener. Next, the samples are sent and carried out using basic characterization of XRD and SEM. The solder is then send for potentiodynamic testing. The secondary characterization was performed after the samples have been corroded. Scanning electron microscope (SEM) and X-ray diffraction (XRD) results confirms that corrosion process occurs on the samples after potentiodynamic testing. The three phase of Ag3Sn, Cu6Sn5 and β-Sn, were presented on the SAC305 samples. From the result of polarization, SnO and SnO2 in a passivation layer formed to provide increased protection to the SAC305 solder for next corrosion attack. The graph of Ecorr and Icorr against the different scan rate in the potentiodynamic scan rate is shown. From the graph of Ecorr, it can be conclude that 2.5mV/s is the most active scan rate towards the environment. Whereas for the graph of Icorr , it displays that Icorr is not affected by the scan rate.