Abstract: A zirconia-base sintered body comprising a sintered substrate containing 30% by volume or more of tetragonal zirconia and a coating film disposed thereon, characterized in that the diffusion coefficient of oxygen in a material forming said coating film at no higher than 550.degree. C. is smaller than that of oxygen in said tetragonal zirconia at a temperature of no higher than said temperature.

Abstract: Disclosed is a curable composition which is superior in chemical resistance and weather resistance and appearance by the use of oxazolidine compounds, comprising (A) a compound having a carboxylic anhydride group, (B) an oxazolidine compound and (C) a polymer containing an alkoxysilyl group. An epoxy compound (D) may be added to the composition.

Abstract: AlN-base sintered body with a high thermal caonductivity is produced by:preparing a compact of a material comprising 100 parts by weight of aluminum nitride and 0.1-10 parts by weight, calculated on metal element, of at least one component selected from the group consisting of elements of Groups 4a, 5a and 6a of the Periodic Table, and compounds thereof; andsintering said compact at a temperature ranging from 1500.degree. to 2000.degree. C. under a non-oxidizing atmosphere having a source of boron and/or carbon supply. The compounds include oxides, borides, nitrides and carbides. The elements include W, Mo, Ta and Ti. Oxides are converted to other compounds through sintering. This AlN-base sintered body has good wettability with metal for metallization and enables simultaneous sintering with metallization layer. Multilayer laminated circuit boards or substrates thereof can be produced.

Abstract: AlN-base sintered body with a high thermal conductivity is produced by:preparing a compact of a material comprising 100 parts by weight of aluminum nitride and 0.1-10 parts by weight, calculated on metal element, of at least one component selected from the group consisting of elements of Group 4a, 5a and 6a of the Periodic Table, and compounds thereof; andsintering said compact at a temperature ranging from 1500.degree. to 2000.degree. C. under a non-oxidizing atmosphere having a source of boron and/or carbon supply. The compounds include oxides, borides, nitrides and carbides. The elements include W, Mo, Ta and Ti. Oxides are converted to other compounds through sintering. This AlN-base sintered body has good wettability with metal for metallization and enables simultaneous sintering with metallization layer. Multilayer laminated circuit boards or substrates thereof can be produced.

Abstract: Whisker-reinforced ceramics with high fracture toughness and strength consists essentially of 5-40 weight % SiC including SiC whiskers, 1-30 weight % of at least one kind of oxides of elements selected from the group consisting of Al, Sc, Y and rare-earth elements, and the balance being silicon oxynitride constituents, wherein said SiC whiskers are present in an amount of no less than 5 weight % of the total essential constituents.The silicon oxynitride constituents are Si.sub.2 N.sub.2 O or a mixture of silicon nitride and silica (0.83-1.22 by molar ratio), or a mixture of Si.sub.2 N.sub.2 O and said mixture of silicon nitride and silica. Silicon oxynitride and SiC phases are predominant.

Abstract: A composite ceramic material reinforced with silicon carbide whiskers consists essentially of 5 to 45% by weight of SiC whiskers, 3 to 20% by weight of at least one selected from the group consisting of oxides and oxynitrides of zirconium calculated on zirconium, and the balance being a SiZlON-based ceramic substance. The SiAlON-based ceramic substance consists essentially of a substance selected from the group consisting of .beta.-SiAlON represented by a compositional formula of Si.sub.6-z Al.sub.z O.sub.z N.sub.8-z (where 0<z.ltoreq.1) and an .alpha.,.beta.-composite SiAlON made up of said .beta.-SiAlON and an .alpha.-SiAlON of the formula M.sub.x (Si,Al).sub.12 (O,N).sub.16, where M denotes at least one selected from the group consisting of Li, Ca, Mg, Y and rare earth metals and 0<x.ltoreq.2; and 1 to 25% by weight of a glass phase containing therein Zr, Si, Al, O and N, or further at least one selected from the group consisting of Y, Mg, Ca and rare earth metals.

Abstract: A silicon nitride sintered product comprises, in % by weight, 1 to 10% Mg, calculated as MgO, 1 to 10% Zr, calculated as ZrO.sub.2, 0.1 to 2.0% of at least one of Al, calculated as Al.sub.2 O.sub.3, Li, calculated as Li.sub.2 O, and Na, calculated as Na.sub.2 O, and the remainder being Si.sub.3 N.sub.4 and unavoidable impurities.

Abstract: AlN-base sintered body with a high thermal conductivity is produced by:preparing a compact of a material comprising 100 parts by weight of aluminum nitride and 0.1-10 parts by weight, calculated on metal element, of at least one component selected from the group consisting of elements of Groups 4a, 5a and 6a of the Periodic Table, and compounds thereof; andsintering said compact at a temperature ranging from 1500.degree. to 2000.degree. C. under a non-oxidizing atmosphere having a source of boron and/or carbon supply. The compounds include oxides, borides, nitrides and carbides. The elements include W, Mo, Ta and Ti. Oxides are converted to other compounds through sintering. This AlN-base sintered body has good wettability with metal for metallization and enables simultaneous sintering with metallization layer. Multilayer laminated circuit boards or substrates thereof can be produced.

Abstract: An apparatus and method for inserting optical fibers into a spacer having spiral grooves to produce a spacer type optical fiber cable wherein a torsional force detecting device is formed integrally with the optical fiber gathering device for inserting optical fibers into the spiral grooves. The torsional force exerted on the device by the spacer is detected by a tension/compression measuring device and the axial speed of the spacer is controlled in response to the measured torsional force so as to reduce the torsional force to zero.

Abstract: A composite layer aluminum nitride-base sintered body has on at least one surface of AlN-base sintered body having a first layer and a second layer. The first layer is 100 parts by weight of at least one component selected from the group consisting of W, Mo, borides thereof and carbides thereof as a first component (s), and 0.1-50 parts by weight of AlN second component. The second layer has at least one component selected from the group consisting of W, Mo, borides thereof and carbides thereof. The thickness of said first layer is 0.5-40 .mu.m, and the sum of thickness of the first and second layers is 1-50 .mu.m. The AlN may also include sintering aids of oxides of rare earth metal and alkaline earth metals. Hydrides and oxides of Ti, Zr, Nb, V and Mn may be included in the first layer composition.

Abstract: A microwave absorber composed of dense silicon carbide having an electrical resistivity of one ohm-centimeter or more. In an electron linear accelerator, it is necessary to provide a microwave absorber to absorb excess energy used to accelerate electrons and discharge this excess energy in the form of heat in order for the accelerator to operate safely. The important characteristics are high-frequency wave absorption, good heat resistance, good thermal conductivity, and stability in a vacuum. The invention meets these requirements with a microwave absorber composed of dense silicon carbide. In an electron linear accelerator the absorber is attached to the end portion of an accelerator guide or a branch portion of a power divider to absorb unnecessary wave energy. Such a microwave absorber is found to have characteristics rendering it highly suitable for this application as well as others.

Abstract: Ceramic sintered mass having a mean grain size of no more than 3 microns of high toughness even at high temperatures is obtainable, the mass comprising 30-99.5% by weight of a component A as defined below and the balance being a component B as defined below:Component A: zirconia having a tetragonal and/or cubic system content of no less than 90% by weight, with the proviso that the tetragonal/cubic system ratio by weight is no less than 0.25, said zirconia including a stabilizer of Y.sub.2 O.sub.3, CaO, MgO, etc.Component B: one or more of borides, carbides and nitrides of Al, Si and an element in the groups 4a, 5a and 6a of the periodic table, and Al.sub.2 O.sub.3.The balance may incorporate a further component C, such as SiO.sub.2, Fe.sub.2 O.sub.3 and TiO.sub.2 and the like of no more than 3% by weight in the sintered mass.

Abstract: A silicon carbide-graphite composite material is disclosed. The composite material includes graphite as a secondary phase which is segregated along the grain boundaries of all the silicon carbide grains. The graphite has an average grain size of not more than 3 .mu.m and is present in a proportion of 1 to 20 vol % based on the volume of the silicon carbide. The composite material has a density greater than 90% of the theoretical density. The composite material is a high density and high strength material.

Abstract: A composite layer aluminum nitride-base sintered body has on at least one surface of AlN-base sintered body having a first layer and a second layer. The first layer is 100 parts by weight of at least one component selected from the group consisting of W, Mo, borides thereof and carbides thereof as a first component(s), and 0.1-50 parts by weight of AlN second component. The second layer has at least one component selected from the group consisting of W, Mo, borides thereof and carbides thereof. The thickness of said first layer is 0.5-40 .mu.m, and the sum of thickness of the first and second layers is 1-50 .mu.m. The AlN may also include sintering aids of oxides of rare earth metal and alkaline earth metals. Hydrides and oxides of Ti, Zr, Nb, V and Mn may be included in the first layer composition.

Abstract: A silicon carbide-graphite composite material is disclosed. The composite material includes graphite as a secondary phase which are dispersed uniformly in a grain boundary of the silicon carbide. The graphite have an average grain size of not more than 3 .mu.m and are present in a proportion of 1 to 20 vol % based on the volume of the silicon carbide. The composite material has a density greater than 90% of the theoretical density. A process for producing the silicon carbide-graphite composite material is also disclosed. The composite material is a high-density and high-strength material.

Abstract: A process for producing a silicon carbide heating element is disclosed comprising: adding boron or a boron compound in an amount corresponding to from 0.3 to 3.0% by weight as boron, and carbon or a carbon compound in an amount corresponding to from 0.1 to 6.0% by weight as carbon, to a SiC powder having an average particle size of 1.0.mu. or less; blending and molding the mixture; conducting a primary sintering in vacuum or in an inert atmosphere, except nitrogen; and thereafter conducting a secondary sintering at from 1500.degree. to 2300.degree. C. in a pressurized nitrogen atmosphere to produce a silicon carbide heating element having a density of at least 80% based on the theoretical density and an electrical resistivity of 1.0 .OMEGA.-cm or less.

Abstract: A microwave absorber, particularly, a microwave absorber intended for use in an electron beam accelerator, having an increased maximum power characteristic. The microwave absorber is formed of a body of dense silicon carbide having a hollow portion and a closed tip end portion. A pipe of high melting point glass or alumina is inserted into the hollow portion. Cooling water is guided through the pipe and circulated through the hollow portion of the body of the absorber.

Abstract: A process for producing a ceramic body suitable for surgical implantation that has high strength and toughness and good compatibility with bone material. A porous material is provided by semi-sintering a ceramic compact. The pores in the surface of the porous material are filled with a first powder of either tricalcium phosphate or apatite or both, or with a material of the fine powder and a powder of a material substantially the same as the material of the ceramic compact. The porous material is then fired at the sintering temperature of the ceramic compact. Following sintering, the surface of the porous material is coated with a fine apatite powder or a finally pulverized mixture of apatite and a calcium phosphate base frit. The resulting assembly is then fired at a temperature up to about 1,350.degree. C.

Abstract: A high toughness sintered body is described, consisting essentially of from 40 to 99.5% by weight of Component A, and 0.5 to 60% by weight of Component B, wherein the mean grain size of the sintered body is 3 microns or less, and Components A and B are as follows:Component A: ZrO.sub.2 containing a stabilizer, such as Y.sub.2 O.sub.3, CaO, and MgO, in which the fraction of the tetragonal and cubic ZrO.sub.2 constitutes at least 90% by weight, and the ratio of the tetragonal ZrO.sub.2 to the cubic ZrO.sub.2 is at least 1/3; andComponent B: at least one of Al.sub.2 O.sub.3 and TiN, with impurities being 3% by weight or less of SiO.sub.2, 0.5% by weight or less of Fe.sub.2 O.sub.3, and 0.5% by weight or less of TiO.sub.2, provided that the total amount is 3% by weight or less.

Abstract: A method for manufacture of a high toughness sintered body, characterized by sintering a shaped body of a mixed powder consisting essentially of from 40 to 70% by weight of a first component of powdered ZrO.sub.2 containing at least one stabilizer selected from the group consisting of Y.sub.2 O.sub.3, CaO, and MgO and having an average particle diameter of not more than 1.mu. and from 30 to 60% by weight of a second component of powdered .alpha.-Al.sub.2 O.sub.3 having an average particle diameter of not more than 1 .mu.m, which mixed powder may also contain not more than 3% by weight of SiO.sub.2, not more than 0.5% by weight of Fe.sub.2 O.sub.3, or not more than 0.5% by weight of TiO.sub.2 in a combined proportion of not more than 3% by weight at a temperature in the range of from 1400.degree. C. to 1600.degree. C. under normal pressure thereby producing a sintered body wherein at least 90% by weight of ZrO.sub.