Ceramic rotor and manufacturing process therefor

A ceramic rotor of a unitary structure, comprising integrally formed blade portions which include a completely smooth conical female surface, said blade portions comprising ceramics sintered at atmospheric pressure, a blade-holding portion which includes a completely smooth conical male surface, said blade-holding portion comprising ceramics sintered at atmospheric pressure, said blade-holding portion having a density which is greater than that of said blade portions, and a cement portion between said smooth conical female surface and said smooth conical male surface, said cement portion for fixing said blade portions to said blade-holding portion, said blade portions having front surfaces defining a first plane and rear surfaces defining a second plane, said second plane intersecting a central axis of said blade-holding portion at a first point and being spaced from said first plane by a distance d.sub.3 along said central axis, said blade portions having interblade center lines defining a curved surface surrounding said central axis, said cemented surface being located between said curved surface and said central axis in a relationship such that a distance d.sub.1 from an arbitrary point on said cemented surface to said first point along a straight line therebetween is less than said distance d.sub.3 but not less than a distance d.sub.2, said distance d.sub.2 being measured from said arbitrary point on said cemented surface to said curved surface taken along said straight line, specifically, d.sub.1 <d.sub.3 and d.sub.1 .gtoreq. d.sub.2.