Crystallization of yttrium aluminum perovskite at around room temperature

The possibility of obtaining crystalline aluminum perovskite from yttria and alumina powders during milling without heating was demonstrated. The reaction is considered to be a sort of over-milling effect. The ball-milling process destroys the crystal of both yttria and alumina by a sort of cold-welding through the collisions between the ball-powder-balls and ball-powder-vials. The heat of mixing for yttria and alumina then becomes negative, allowing Y-Al-O nonequilibrium phase to form spontaneously by interdiffusion across the particle surface. As the starting materials were extremely fine, the reaction field is huge and the efficiency of the reaction increases enormously.