Effects of Organic Template Pore Size and Sintering Temperature on Structure and Properties of SiC Foam Ceramics
SiC foam ceramics,as a new type of porous materials,are widely used in metallurgy,petrochemical,aerospace,biomedicine and other fields due to its excellent properties of high strength,high hardness,corrosion resistance,and high temperature resistance.SiC foam ceramics were prepared by organic template impregnation with SiC as the main raw material and Al2O3 as the sintering aid.The effects of the organic template pore size and sintering temperature on macro and micro morphologies,phase composition,porosity and compression properties of the SiC foam ceramics were studied.Porosity of the SiC foam ceramics increased from 48.3％to 75.6％,as the pore size of the organic template increased from 35 ppi to 20 ppi,while the compressive strength decreased from 1.94 MPa to 0.4 MPa.As the sintering temperature was increased from 1350 ℃ to 1500 ℃,porosity of the SiC foam ceramics decreased from 78.7％to 68.3％,while the compressive strength first increased and then decreased.The SiC foam ceramic sample prepared at 1450 ℃ has the highest compressive strength(1.45 MPa)with a porosity of 71.6％.The pore structure is complete and particles are tightly packed.In addition,there are fewer pinholes,cracks and brittle phase cristobalite in the samples.
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