IN-SITU OBSERVATION OF DISCRETE GLASSY SIO2 FORMATION AND QUANTITATIVE-EVALUATION OF GLASSY SIO2 IN MOSI2 COMPACTS

Properties, distribution and quantity of grain boundary glassy SiO2 ar e very important factors to determine the mechanical properties of MoS i2 sintered bodies. The formation mechanism of discrete glassy SiO2 in MoSi2, and sintering mechanism of a MoSi2 powder were clarified by in situ SEM observation method using a new type of direct heating stage with small thermal drift. Furthermore, the glassy SiO2 in sintered MoS i2 was quantitatively evaluated by the cryogenic specific heat measure ments, which has been developed for Si3N4 based materials. Combining t hese method enables precise evaluation of sintered MoSi2 based materia l. (C) 1998 Elsevier Science B.V. All rights reserved.