Effect of Ga Content on High-Temperature Oxidation of (Cu,Ga) Solid Solution Powders

Abstract

Copper and its alloys are widely used in different industrial fields, but environmental impact could lead to corrosion and therefore may result in poor performance of these materials. To ensure safe operation of the equipment, it is necessary to study the corrosion behavior. Here, we introduce a novel study of the kinetics of complete isothermal oxidation in air of pure Cu and Cu1–xGax (0 < x < 0.15) solid solution powders by the periodic weighment method and XRD phase analysis. It is shown that experimental oxidation curves for each Ga-containing sample studied are perfectly described by single-term exponential function. Analysis of these curves made it possible to calculate the main oxidation parameters of Cu1–xGax powders. As a result, it was shown that the activation energy of oxidation increases from 98 to 114 kJ/mol with Ga content increasing from 0 to 12 at.%, while the oxidation rates decrease by almost 100 times. Oxidation of Cu1–xGax powders is accompanied by the depletion of initial solid solution with Ga atoms followed by the formation of Ga2O3, CuO and CuGa2O4 phases. Thus, Ga dopants significantly increase the corrosion resistance of copper at annealing in air (600–850 °C). The results obtained contribute to the optimization of Cu1–xGax solid solution content for development of the targets for deposition of multilayer coatings for technical or medical purposes, for example, CuIn1–xGaxSe2 for solar cells or thin copper–gallium-doped silica-rich bio-active glass implant-type coatings.