| 摘 要： | In order to reduce the sintering temperature and improve the properties of sintered corundum, corundum specimens were prepared by granulation and sintering with nano-η-Al_2O_3 as the raw material and polyvinyl alcohol as the binder. The effects of different sintering temperatures(1 550, 1 600, 1 650 and 1 700 ℃) and holding time(2, 4 and 6 h) on the properties and microstructures of the specimens were studied, and the transformation mechanism of η-Al_2O_3 was analyzed. The results show that dense sintered corundum with bulk density of 3.74 g/cm~3 and apparent porosity of 1.77% is obtained by calcinating at 1 650 ℃ for 6 h; the phase transition from η-Al_2O_3 to α-Al_2O_3 occurs first on the surface of alumina particles and then diffuses rapidly to the interior; at lower sintering temperatures there is no abnormal growth of crystals, the bonding between the grains is tight, transgranular fracture is the main fracture mode, there are fewer intergranular pores, and the grain size is in the range of 3.5-7.5 μm.
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