Synthesis and high-pressure sintering of lanthanum magnesium hexaaluminate

摘要

Lanthanum magnesium hexaaluminate is a very important ceramic material for high temperature applications. In this paper lanthanum magnesium hexaaluminate has been synthesized directly by solid-state reaction. The forming mechanism was investigated by XRD. The SEM photographs show that the prepared powders are made of hexagonal plates. These powders can be well sintered at the high temperature (1600 ℃) under the high pressure (4.5 GPa), and the relative density reaches 94.8%. The hardness of the high-pressure sintered lanthanum magnesium hexaaluminate is tested to be 16.68 GPa, which is much larger than that of pressureless sintering. Toughness of high-pressure sintered lanthanum magnesium hexaaluminate is about 5.25 MPa m~(1/2).