The effect of water-soluble CaCl2 on the properties and microstructure of calcium aluminates cement bonded corundum based castable has been investigated.When the castables were fired at 1450°C for 3h,well dispersed CA6 was produced in the matrix of the castable with 1.5 wt％ CaCl2,owing to the in situ reaction of Al2O3 with the well dispersed CaCl2 at high temperature.The content of CA6 phase increased significantly with the introduction of CaCl2.As the thickness of the plate-like CA6 is only about 100 nm,a large amount of microcracks or tiny gaps among CA6 grains are well dispersed in the matrix,which lead to the increase of apparent porosity and to the decrease of the mechanical strength of castable with 1.5 wt％CaCl2.Nevertheless,these well dispersed microcracks or tiny gaps will be very helpful to improve the thermal shock resistance of castable;additionally,because of the mismatch of thermal expansion coefficient between CA6 and alumina,more micro-cracks will possibly generate by the presence of well dispersed CA6 during the employment under high temperature,which will be also beneficial to improve the thermal shock resistance of castable.
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