Glass formation of rare earth aluminates by containerless processing

xR2O3–(100 − x)Al2O3 binary glasses (R = Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) were synthesized by containerless processing using an aerodynamic levitation furnace. Transparent glasses with a composition of x = 30 and 32 were obtained for all Rs except Yb and Lu, which contained a small amount of crystalline phases. The glass transition temperature for x = 32 glasses increased with a decrease in the ionic radius of R while the thermal stability of the glass and the molar volume decreased. From the results of the relation between the glass forming region and the phase equilibrium, it is proposed that solidification by containerless cooling proceeds as expected from the non-equilibrium phase diagram in the binary systems of small R (R = Y, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu).

► We determine glass forming region of rare-earth oxide-alumina glasses. ► Glass transition temperature and density decreased linearly with the ionic radius. ► Glass with a smaller ionic radius of R has a denser packed structure.