A processing strategy is presented for obtaining alumina-spodumene ceramics
with controlled microstructures from a new, low-cost alumina powder and sp
odumene (Li2O . Al2O3. 4SiO(2)) mineral, both being produced in Western Aus
tralia. The addition of 15 wt% beta-spodumene to alumina is used to produce
ceramics with (i) high thermal expansion mismatch and (ii) a glassy phase
to aid in liquid-phase sintering, Specifically, the effects of spodumene ad
dition and grain size on tolerance to thermal shock are addressed, The ther
mal shock resistance of the alumina-spodumene ceramics is evaluated by wate
r quenching and subsequent three-point bend testing of strength diminution,
Comparisons are made with results from parallel experiments conducted usin
g a pure monolithic alumina ceramic, The reference alumina shows the expect
ed substantial strength losses when thermally quenched from similar to 200
degrees C above room temperature. By contrast, the alumina-spodumene cerami
cs, while displaying reduced strength relative to the reference aluminas, e
xhibit minimal strength degradation under severe thermal shock conditions.