High-temperature oxidation behavior of Cu64Zr36 metallic glass powders
(1. State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China;
2. State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China;
3. School of Mechanical Engineering, Wuhan Polytechnic University, Wuhan 430023, China;
4. School of Mechanical Engineering and Automation, Wuhan Textile University, Wuhan 430073, China)
2. State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China;
3. School of Mechanical Engineering, Wuhan Polytechnic University, Wuhan 430023, China;
4. School of Mechanical Engineering and Automation, Wuhan Textile University, Wuhan 430073, China)
Abstract: Cu64Zr36 metallic glass powders were prepared via gas atomization. The high-temperature oxidation behavior of Cu64Zr36 metallic glass powders under the influence of internal factors (powder particle size) and external factors (oxidation temperature and oxidation time) was experimentally investigated by using XRD, DSC, TGA, SEM and TEM. The oxidation kinetics, oxide phase, surface morphology and microstructure of metallic glass powders were analyzed. The results show that Cu64Zr36 metallic glass powders form multiple layers of surface oxides after oxidation and the major components of the surface oxides are t-ZrO2, m-ZrO2, Cu2O and CuO. The oxidation kinetics follows a double-stage parabolic rate law. The oxidation process is dominated by the inward diffusion of O anions and the outward diffusion of Cu cations. Thermodynamic analysis shows that the Gibbs free energy change of the oxidation reaction increases with the decrease of particle size, leading to a more rapid and thorough oxidation of the powder with a smaller particle size.
Key words: metallic glass powder; high-temperature oxidation; thermodynamic analysis; ionic diffusion; parabolic rate law