High-temperature mechanical properties of a solid oxide fuel cell glass sealant in sintered forms

High-temperature mechanical properties of a silicate-based glass sealant (GC-9) for planar solid oxide fuel cell have been studied in sintered forms. Ring-on-ring biaxial flexural tests are carried out at room temperature to 800 degrees C for the sintered GC-9 glass. The results are also compared with those in cast bulk forms. From the force-displacement curves, the glass transition temperature (T(g)) of the non-aged, sintered GC-9 glass is estimated to be between 700 degrees C and 750 degrees C, while that of the aged one is between 750 degrees C and 800 degrees C. Due to a crack healing effect of the residual glass at high temperature, the flexural strength of the sintered GC-9 glass at temperature of 650 degrees C to T(g) point is greater than that at room temperature. At temperature above T(g), the flexural strength and stiffness are considerably reduced to a level lower than the room-temperature one. The sintered GC-9 glass with pores and crystalline phases has a flexural strength lower than the cast bulk one at temperature of 650 degrees C and below. Due to a greater extent of crystallization, the flexural strength and stiffness of the sintered GC-9 glass are greater than those of the cast bulk one at 700-800 degrees C. (C) 2010 Elsevier B.V. All rights reserved.