MECHANICAL-PROPERTIES OF SIC WHISKER-REINFORCED MULLITE COMPOSITES (PART 1) - EFFECTS OF DISPERSANT CONTENTS IN MIXING SOLVENTS ON THE STRENGTH AND MICROSTRUCTURE OF SINTERED BODIES

The dispersibility of mixed powder consisting of mullite and SiC whisk er in solvents was assessed by carrying out sedimentation tests and vi scosity measurements. The dispersibility was improved with increasing dispersant content and became goad by adding dispersant over 0.5 mass% . On the other hand, the dispersibility of mixed powder consisting of mullite and carbon-coated SiC whisker W (AC) was better than that of m ixed powder consisting of mullite and W (A), despite the dispersibilit y of W (AC) being worse than that of W(A) if their particles existed a lone in solvent. However, the dispersibility of the mixed powder consi sting of mullite and W(AC) was lowered on addition of 0.5 mass% disper sant and improved again on addition of 1.0 mass%. The strength of SiC whisker-reinforced mullite composites became maximum by addition of 0. 5-1.0 mass% dispersant to the solvent used in powder-mixing.