In situ hot pressing/reaction synthesis, mechanical and thermal properties of Lu_2SiO_5

摘要

Lu_2SiO_5 is a promising candidate of environmental barrier coatings (EBC) for silicon based ceramics due to its excellent high temperature stability. However, little information is available for the mechanical and thermal properties of Lu_2SiO_5, which frustrated evaluation of its performances for EBC applications. In this paper, dense Lu2SiC>5 ceramic is successfully fabricated from Lu_2O_3 and SiO_2 powders by in situ hot pressing/reaction sintering at 1500 °C. Mechanical properties, including Young's modulus, bulk modulus, shear modulus, Poisson's ratio, fracture toughness, Vickers hardness, and bending strength are reported for the first time. Lu_2SiO_5 possesses excellent high temperature mechanical properties up to at least 1300 °C. Thermal stress for the case of Lu_2SiO_5 or Y_2SiO_5 coating on silicon bond coat and thermal stress resistance parameter are also estimated based on the experimental mechanical and thermal properties. The present results suggest that Lu_2SiO_5 has better reliability than Y_2SiO_5 in harsh thermal environment.