Study the effect of kaolin addition on some physical and mechanical properties of α-SiC powder

Abstract

The present work investigates the physical and mechanical properties based on α-SiC powder with different percentage addition of Duekhla raw kaolin. Samples have been prepared utilizing powder technology technique, then formed by uniaxial pressing and sintered at 1400 ˚C. The apparent density (A.D.) and apparent porosity (A.P.) for each sample were evaluated as a function of kaolin percentage. It was shown that the A.D. and A.P. decreasing with increasing kaolin content. These results are interpreted in view of that, the kaolin have density lower than the SiC. Mechanical properties show that the compressive strength, diametrical strength and hardness of ceramic samples increased significantly with increasing of kaolin content until it reached a maximum value with 20% kaolin addition. This phenomenon may be attributed to the presence of alumina and silica in kaolin composition which formed a new phases enhancement the mechanical properties of the prepared ceramic.