Depth Profiling Analysis of Tarnish Films on Copper Formed during Short-Term Outdoor Exposure by Glow Discharge Optical Emission Spectroscopy

Abstract

Abstract The elemental depth profiling of tarnish films were analyzed at the early stages of atmospheric copper corrosion by glow discharge optical emission spectroscopy (GDOES), where the tarnish films had been formed by exposing copper plates to various outdoor environments, i.e., urban, rural/coastal, and hot-spring sites, for 1 month. Since GDOES probed a large surface area, on the order of millimeters, the depth profiles reflected macroscopic-averaged characteristics over this area, which are representative of real corroded surfaces. GDOES complemented previous analyses, i.e., Auger electron spectroscopy (AES), x-ray diffraction, field-emission scanning electron microscopy (FE-SEM), coulometric reduction, and x-ray photoelectron spectroscopy, and provided a better understanding of these tarnish films. In particular, the previous findings from microscopic FE-SEM observation and AES depth profiling were well supported by the GDOES results. With GDOES we observed the generation and distribution of cupri...