Abstract: An air cushioned bearing includes: a cylindrical arbor; and an axial bushing formed as a hollow cylindrical tube for rotationally accepting the arbor; wherein a spiral groove or a spiral flange rib is formed between the arbor and the axial bushing. Therefore, the arbor rotates in high speed to form an air cushion between the axial bushing and the arbor.

Abstract: A sintered silicon carbide (SiC) body prepared by a process which contains the steps of: (a) preparing a raw batch containing: (i) a raw silicon carbide mixture containing about 10 to about 90 weight percent of an .alpha.-phase SiC powder and about 90 to about 10 weight percent of a .beta.-phase SiC powder; (ii) aluminum oxide (Al.sub.2 O.sub.3) powder, about 3 to 15 weight percent of the raw silicon carbide mixture; (iii) yttrium oxide (Y.sub.2 O.sub.3) powder, about 2 to 10 weight percent of the raw silicon carbide mixture; (iv) an organic binding agent and a dispersing agent; and (v) deionized water; (b) drying the raw batch to form a green body; (c) heating the green body at temperatures between about 400.degree. and 800.degree. C. to remove the organic binding agent and the dispersing agent; and (d) subjecting the green body to a two-stage pressureless sintering process, first at a first sintering temperature between about 1,800.degree. and about 1,950.degree. C. for 0.5 to 8.