Pressure Sintering: Mechanisms and Microstructures for Alumina and Magnesia

摘要: Pressure sintering (or hot-pressing) of pure alumina and magnesia in graphite dies ceramic over the range 1100° to 1700°C 4000 10,000 psi has been shown be very useful fabricating these materials with controlled microstructures (e.g., high relative density fine grain size or larger sizes) without use additives control size. Apparent diffusion co-efficients calculated for densification process are orders magnitude greater than pressureless sintering, which might explained by enhanced under stress. Alternatively, however, lower coefficients more agreement pressureless-sintering data result when pressure correction terms, modified porosity, applied existing relations. It is concluded that consistency as well reasonable comparison activation energies suggests that, pressures used, beyond initial stages a diffusion-controlled process.