They found that at 100–500 ☌ the corrosion products were flaky, and the thickness of the products varied from 50 nm at 100 ☌ to micro-meters at 500 ☌, whereas at 800 ☌ they were netlike porous tissues. focused their research on the oxidation of copper in air at temperatures ranging from room temperature to 900 ☌. Electrochemical reduction analysis of oxidized massive copper samples indicated that the oxide film is mostly Cu 2O, and CuO develops only after several days at 90–100 ☌. Although SEM-EDS analyses in TGA tests indicated that oxygen was adsorbed on the copper surface, neither XRD patterns nor Raman spectroscopy measurements showed any trace of Cu 2O or CuO formation on the copper surface. Oxidation at 90–100 ☌ produced 40 nm thick films in a day and over 100 nm films in a week. With QCM, oxidation at 60–80 ☌ produced less than 40 nm films in 10 days. Temperature and exposure time appeared to have a large effect on oxide film thickness and composition. In QCM tests using electrodeposited copper film, the weight change was rapid at the beginning but slowed to a linear relationship after few minutes. In thermogravimetric tests the mass of the copper sample increased until the oxidation gradually slowed down and finally started to decrease due to cracking and spalling of the oxide formed on the surface. The weight change in thermogravimetric tests showed periodic weight increase and decrease. The aim of this study was to investigate the oxidation kinetics of copper at low temperatures (60 ☌ to 100 ☌) in air by isothermal thermogravimetric analysis (TGA) and quartz crystal microbalance (QCM).
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