| 摘要 |
PURPOSE:To produce a silicon nitride composite material having high strength and high toughness by forming a fine composite structure contg. silicon carbide particles dispersed among groups of silicon nitride-based grains. CONSTITUTION:One or more kinds of oxides or nitrides selected from among oxides of group IIIa elements of the Periodic Table, Al2O3, MgO, CaO, ZrO2 and AlN are added by 0.2-10.0wt.% to silicon nitride powder, they are granulated to 10-50mum average particle diameter and 0.1-5.0wt.% carbon is deprosited to the peripheries of the granulated particles by heating to 500-1,000 deg.C in gaseous propane. The particles are then compacted and fired at 1,600-2,100 deg.C under 1-500atm pressure of gaseous nitrogen to obtain the objective silicon nitride composite material having a fine composite structure in which 0.2-10.0wt.% silicon carbide is contained, silicon nitride forms groups of silicon nitride-based grains as lumps of polycrystals having 10-50mum average diameter and silicon carbide particles have been dispersed among the groups. |
