Phenomenology of corundum crystal formation in supercritical water fluid

This paper describes a solid phase transformation of aluminium hydroxide into oxyhydroxide (boehmite), and then into well formed fine crystals of corundum (α-Al 2 O 3 ) in the medium of a supercritical water fluid at a temperature of 450 °C and a pressure of 30 MPa. Using electron microscopy the development and processing of corundum crystal formation from incipient crystals to crystal growth and their perfecting is traced.