Low-temperature Sn electrodeposition: Texture evolution, grain boundary constitution and corrosion behavior

Abstract

Electrodeposition of Sn was conducted at three different electrolyte bath temperatures: 25 °C, 20 °C, and 15 °C in galvanostatic conditions. Corrosion analysis using the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization revealed that decreasing the electrodeposition bath temperature reduced the corrosion resistance of Sn coatings. The 25 °C coating exhibited the highest polarization resistance (Rp) value of 71,460 Ω.cm2 and lowest corrosion current density (icorr) value of 0.251 μA.cm−2, whereas the 15 °C coating exhibited Rp value of 16,120 Ω.cm2 and icorr value of 0.891 μA.cm−2. The electrochemical response was correlated with the texture and grain boundary constitution using the electron backscatter diffraction (EBSD) technique. It was observed that decreasing the electrodeposition temperature decreased the predominance of the (100) texture, increased the strain, and reduced the average grain size of Sn grains. The Sn coating with the lowest corrosion resistance displayed a predominant (501) texture, lowest grain size, and highest strain within the Sn grains.