Mechanical alloying of Ga2O3 and Ga2O3-Al2O3

Mechanical milling of Ga2O3 powder and a mixture of Ga2O3 and Al2O3 was performed with the intent to prepare a (AlGa)(2)O-3 alloy. Vibrational milling was conducted with stainless steel or zirconia ceramic balls. The milled samples were characterized using X-ray diffraction (XRD) analysis, Raman spectroscopy, and microscopic observation. During the mechanical milling of Ga2O3, the monoclinic beta-Ga2O3 phase was transformed into the corundum alpha-Ga2O3 phase, and the phase transition was presumed to be similar to that induced by pressure loading. The fraction of alpha-Ga2O3 phase increased with milling time in a manner consistent with the Johnson-Mehl-Avrami (JMA) equation. Mechanical alloying of the Al2O3-Ga2O3 system was performed for 1200 h. Although the XRD and Raman peaks for both alpha-Al2O3 and alpha-Ga2O3 were broadened with increasing alloying time, and some of the peaks gradually merged, no distinct evidence of the production of single-phase (Al0.5Ga0.5)(2)O-3 was obtained. It is thus difficult to synthesize the (Al0.5Ga0.5)(2)O-3 phase by powder metallurgy methods.