The layup was then loaded into a graphite die and placed in the
hot press (HP20-3060-20, Thermal Technology, Santa Rosa, CA). Binder
removal was conducted by heating under vacuum (~20 Pa) to 600 °C
with no applied pressure. The atmosphere was then changed to argon,
a uniaxial load of 32 MPa was applied and the furnace was ramped to
the sintering temperature at ~25 °C/min. The maximum sintering temperature
was set to 1450 °C on the basis of previous analysis of shrinkage
curves. After 40min at the sintering temperature, the furnace power
was turned off and the specimen was allowed to cool naturally.