| 摘要 |
PURPOSE:To facilitate working of blank materials, to maintain accuracy and to obtain a spacer pad of high abrasion resistance by using a sintered body of silicon nitride or silicon carbide as a material for the spacer pad. CONSTITUTION:A sintered body of silicon nitride or silicon carbide having superior strength in high temp. and abrasion resistance is utilized as a material for a spacer pad of a wrapper pipe. For example, a silicon compound is sintered with an HIP or hot press or is sintered by adding several % MgO or Al2O3 or Y2O3 at ordinary temp. With addition of deformation by this sintering, the powder of the silicon compound is die-stamped with a press, whereby the accuracy of sizes is maintained. In addition, the silicon nitride and silicon carbide have high hardness and are maintained up to around 1,300 deg.C, whereby high abrasion is provided, and further the deformation at elevated temp. is prevented since the coefft. of thermal expansion is minimal. |
