摘要:
Processes for the production of a silicon nitride sintered body are disclosed. One process comprises molding a mixed powder of 100 parts by weight of metallic silicon with a maximum particle size of 20 .mu.m or less and 0.2 to 2 parts by weight (calculated as chromium oxide) of a chromium component and, thereafter, reaction sintering the mold in a nitrogen gas or in a non-oxidizing atmosphere containing nitrogen gas at a temperature of 1,300.degree. to 1,500.degree. C. This invention provides further process which comprises molding a mixed powder of 100 parts by weight of metallic silicon with a maximum particle size of 20 .mu.m or less, 0.2 to 1 part by weight (calculated as chromium oxide) of a chromium component, and further 10 to 20 parts by weight of an oxide component of one or more of the oxides of yttrium, lanthanum, cerium, gadolinium, and erbium, reaction sintering the above-prepared mold, and thereafter, hot pressing the reaction sintered body. This silicon nitride hot pressed body is superior in oxidation resistance, and moreover is of high density and has high mechanical strength. Thus it is suitable for use as, e.g., gas turbine parts of diesel engine parts.
摘要:
A sintered silicon nitride products and processes for the fabrication thereof are described, wherein the product comprises from 60 to 98.9% by weight of silicon nitride, from 0.1 to 15% by weight of one or more chromium components selected from metal chromium, chromium oxide, and chromium nitride, and from 1 to 25% by weight of one or more oxides selected from oxides of rare earth elements, scandium oxide, yttrium oxide, aluminum oxide, zirconium oxide and silicon dioxide.
摘要:
A silicon nitride sintered product and processes for the production thereof are described, wherein the product comprises from 75 to 97.9% by weight of silicon nitride, from 2 to 20% by weight of yttrium oxide and cerium oxide in a molar ratio of cerium oxide to yttrium oxide of 0.4/1 to 4/1, and from 0.1 to 8% by weight of aluminum oxide.
摘要:
A process for producing a silicon nitride sintered product having high toughness is described, comprising blending from 97 to 57% by weight of metallic silicon powder having a maximum particle size of 25 .mu.m or less with from 1 to 15% by weight, calculated as TiN, of a TiN powder having a maximum particle size of 20 .mu.m or less or a powder of titanium component capable of changing into TiN during reaction sintering, and from 2 to 28% by weight of one or more components selected from the group consisting of AlN, Al.sub.2 O.sub.3, SiO.sub.2 and oxides of rare earth elements, molding the resulting mixture, carrying out reaction sintering in a nonoxidizing atmosphere of a nitrogen gas or a nitrogen-containing mixed gas, and thereafter resintering in the same atmosphere at a temperature of from 1,600.degree. C. to 2,200.degree. C.
摘要:
A silicon nitride based ceramic tool is disclosed which is prepared from the starting powder compositions surrounded by and including the lines defined by the points A, B, and C and preferably D, E, and F in the FIGURE.
摘要:
A high strength silicon nitride sintered material having a modulus of rupture of about 100 kg/mm.sup.2 or more, which is prepared by sintering a mixture of about 88.7 to 98% by weight of silicon nitride (Si.sub.3 N.sub.4) and the balance a sintering aid comprising Al.sub.2 O.sub.3, Y.sub.2 O.sub.3 and Ti present in the following proportions based on weight: ##EQU1##
摘要翻译:通过烧结约88.7-98重量%的氮化硅(Si 3 N 4)的混合物制备的具有约100kg / mm 2或更高的断裂模量的高强度氮化硅烧结材料,其余为包含Al 2 O 3的烧结助剂 ,Y 2 O 3和Ti以以下重量比例存在:
摘要:
A process for producing high density sintered product which comprises molding a composite of an inorganic powder and an organic resin, burning off the organic resin, coating the surface of the molding with a rubber film, pressing said moldings under 2 ton/cm.sup.2 or more of isostatic pressure, and sintering.
摘要:
A ceramics spike pin is provided with a pin body having a horizontal cross section of a substantially circular shape, which pin body is provided with a rounded free end portion having a predetermined radius of curvature and a connecting base portion having a predetermined radius of curvature, and a horizontally expanded base connected to the connecting base portion, wherein a diameter (d) of the connecting base portion in horizontal cross section, the radius of curvature(r) of the connecting base portion, and a maximum diagonal length (D) of the horizontally expanded base satisfy the relationship of 0
摘要:
A bearing includes an inner ring made of ceramics. A shaft is made of metal and fitted in the inner ring. The ceramics has a tensile strength equal to or larger than 50 Kg/mm.sup.2, and the ceramics and the metal are determined so as to satisfy the relation of .beta..sub.2 -.beta..sub.1 .ltoreq.6.times.10.sup.-6 /.degree.C. where .beta..sub.1 is a coefficient of linear expansion of the ceramics and .beta..sub.2 is a coefficient of linear expansion of the metal.
摘要:
A method of improving the impact resistance of a ceramic turbine rotor by rotating the rotor in a number of abrasive grindstones such that the edges of the rotor are rounded to a radius in the range of about 0.2 to 1 mm.