Based on the theoretical
temperature and pressure as determined by the Al 2O 3-H 2O phase state diagram, and considering the influencing factors of
hydrothermal corundum such as the reaction materials' compositions, grit sizes and heating evenness, this paper studied how reaction pressure (P), temperature(t) and
insulation time (T) affect the grain sizes and shapes of micropowder so as to optimize the P-T relation curve By making experiments on different T-P-t relations, a T-P-t curve can be found in accordance with expected ideal product The results showed that, if the mineralizer, raw materials, temperature and insulation time are
stable, the higher the pressure is, the larger the grains will become, and the crystallization will be more complete and the conversion rate will be higher; if the mineralizer, raw materials,
pressure and temperature are stable, the longer the insulation time is, the larger the grains will become, the conversion rate of Al 2O 3 will also be higher; if the
synthesis conditions are kept the same, the influence of insulation time on grain size is not as strong as that of pressure