Abstract: A semiconductor-supporting device comprising a substrate made of an aluminum nitride-based ceramic material and having a semiconductor-placing surface, wherein an orientation degree of the aluminum nitride-based ceramic material specified by the following formula is not less than 1.1 and not more than 2.0.Orientation degree=[I'(002)/I'(100)]/[I(002)/I(100)]in which in an X-ray diffraction measurement, I'(002) is a diffraction intensity of a (002) face of the aluminum nitride-based ceramic material when X-rays are irradiated from the semiconductor-placing surface, I'(100) is a diffraction intensity of a (100) face of the aluminum nitride-based ceramic material when X-rays are irradiated from the semiconductor-placing surface, I(002) is a diffraction intensity of the (002) face of the aluminum nitride ceramic according to a JCPDS Card No. 25-1133, and I(100) is a diffraction intensity of the (100) face of the aluminum nitride ceramic according to a JCPDS Card No. 25-1133.

Abstract: A porous, flow-through molded body, designed specifically for use in the removal of diesel soot particles from the exhaust gas of diesel engines. It includes a reciprocally closed honeycombed body made of silicon carbide and possessing the following features.wall thickness: 1.25.+-.0.5 mm;porosity: 55 to 60%;average pore diameter: 25 to 70 .mu.m;specific permeability: 20 to 100 nPm.In the production method, a starting powder of silicon or a mixture of silicon with portions of silicon carbide and/or carbon is combined with an organic binding agent that can be coked and molded into a green body. This is then subjected to a coking fire in an inert-gas atmosphere; the molded body obtained in this manner is then heated in the presence of nitrogen or a nitrogenous inert gas to a temperature where free silicon is converted with the carbon, in a reaction firing, to silicon carbide. Additionally, a recrystallization firing at greater than 2000.degree. C. is implemented.

Abstract: A controlled dielectric loss, sintered aluminum nitride body having a density of greater than about 95% theoretical, a thermal conductivity of greater than about 100 W/m-K, and a dissipation factor measured at room temperature at about 1 KHz selected from:(a) less than or equal to about 0.001; and(b) greater than or equal to about 0.01.A process for producing a controlled dielectric loss, sintered aluminum nitride body, comprising heat treating an aluminum nitride body at sintering temperatures, including providing a heat treatment atmosphere which effects a selected nitrogen vacancy population in the aluminum nitride body at the sintering temperatures, and cooling the aluminum nitride body from sintering temperatures at a controlled rate and in a cooling atmosphere effective to control the selected nitrogen vacancy population.

Abstract: A silicon nitride sintered body prepared through a nitriding reaction of Si, consists of crystal grains mainly composed of silicon nitride and/or SIALON and a grain boundary phase. The grain boundary phase includes a first component including at least one element selected from a group of Na, K, Mg, Ca and Sr and a second component including at least one element selected from a group of Y and lanthanoid series elements. The molar ratio of the first component to the second component is in the range of 1:1 to 6:1 in terms of oxides. The mean breadth and the mean length of the crystal grains are not more than 0.1 .mu.m and not more than 3 .mu.m respectively, and the standard deviation of the mean length in the sintered body is within 1.5 .mu.m. Especially, the mean breadth of the crystal grains is at least 0.4 .mu.m and not more than 0.9 .mu.m.

Abstract: A conductive wire is electrically heated in a gas atmosphere, wherein a gas reacts with a constituent material of the conductive wire, under gravity-free or micro gravity state. A ceramic is formed on a surface of the wire sa an outer core through a reaction between the wire and the gas and is left by caving an inside wire by melting while maintaining controlled gas convection.

Abstract: The invention relates to refractory materials that may be used in iron and steel metallurgy comprising, in % by weight:A! 32 to 87% of particles and/or grains of at least one refractory material, the melting temperature and thermal dissociation temperature of which are greater than 1700.degree. C.;B! 7 to 50% of an in situ-formed binding matrix and consisting of a sialon, AIN or one of its polytypes, or a mixture thereof;C! 2 to 40% of a material based on titanium nitride TiN dispersed in the matrix; and, optionally,D! 0 to 42% of hexagonal boron nitride, amorphous carbon and/or crystallized graphite dispersed in the binding matrix.

Abstract: A composite powder having a specific surface area of 7 m.sup.2 /g or more is produced by mixing a silicon powder with a carbonaceous powder and a sintering aid powder, and heat-treating the resultant mixed powder in a nitrogen-containing atmosphere at a temperature of 1,450.degree. C. or lower thereby nitriding and carbonizing silicon in the mixed powder. The temperature elevation speed in the heat treatment for nitriding and carbonizing is less than 2.degree. C./minute at least in a range from a temperature at which the nitriding and carbonizing of silicon starts to take place to a temperature at which the composite powder is kept for nitriding and carbonizing of silicon. The composite sintered body is produced by sintering such a composite powder at a temperature of 1,600.degree. C. to 2,200.degree. C.

Abstract: Ceramic granules for producing sintered products of silicon nitride that can be favorably used as structural materials for various heat engines such as automotive parts, gas turbines and the like, and as abrasion resistant materials and corrosion resistant materials. A process for preparing the ceramic granules and a process for preparing sintered products of silicon nitride by using the ceramic granules. Ceramic granules comprise a mixture of a silicon nitride powder, a silicon powder and an assistant, as well as an organic binder, said ceramic granules having an average particle diameter of from 50 to 300 .mu.m and a relative density of from 18 to 30%.

Abstract: Sintered reaction-bonded silicon nitride components, e.g., automotive components, are made by forming a powder mixture comprising silicon and oxide or oxide precursor additives. These additives comprise alumina and a calcium compound. The powder is formed into a preform, the silicon is reacted with nitrogen in a nitriding process to form silicon nitride, and the so-formed silicon nitride is sintered.

Abstract: Boron nitride articles are made by heat treating turbostratic BN powder to reduce its oxygen content to 5-8% (mesographitic BN), washing this heat-treated powder, mixing it with 5-8% amorphous boron, shaping the mixture, explosively compacting the shape by a hydrodynamic method and reaction sintering the compacted shape, to form the article.The article is then buried in a powder mixture of BN and SiC and heat treated, to getter residual B.sub.2 O.sub.3.After this, the article is impregnated with low-viscosity oligomers (MW<1000) of methylsilanes selected to yield a high proportion of SiC on pyrolysis, and the article is heat-treated to fill the pores evenly throughout its thickness with SiC.

Abstract: A ceramic matrix composite material comprising a matrix containing silicon carbide as the primary component and silicon nitride as the secondary component is disclosed. The silicon nitride includes not more than 1% by weight of iron and reinforcements mixed and dispersed. The ceramic matrix composite material is manufactured, for example, by forming a matrix containing reaction sintered silicon carbide as the primary component and nitriding the free metal silicon produced in the sintering process so that the free metal silicon will be converted to fine silicon nitride particles. Said metal silicon used for reaction sintering already contains iron. These processes enable the containing of a comparatively large amount of reinforcements, as well as the improvement of heat resistance of the sintered compact and the suppression of the deterioration of reinforcements.

Abstract: The invention reduces the time required for nitriding in the process of reaction sintering for production of a sintered body of silicon nitride, thereby improving productivity, and provides a sintered body of silicon nitride having sufficient compactness and high strength which can be produced by reaction sintering. The sintered body is Si.sub.3 N.sub.4 having an unpaired electron density of 10.sup.15 /cm.sup.3 to 10.sup.21 /cm.sup.3. The sintered body is produced through reaction sintering by using a Si powder having an unpaired electron density of 10.sup.15 -10.sup.20 /cm.sup.3, which is obtained by annealing a commercially available Si powder at temperatures of 300.degree. to 800.degree. C. in other than nitrogen atmosphere for 3-5 hours.

Abstract: A process for the production of dense silicon nitride materials by the nitriding of moulded bodies of silicon powder, silicon nitride powder and sintering additives under normal pressure and sintering of the moulded bodies at normal nitrogen pressure as well as silicon nitride materials produced correspondingly.

Abstract: A process for the production of refractory materials containing SiALON and carbon or SiALON/SiC and carbon. The process for producing a refractory material containing SiALON and carbon includes heating a molding containing silicon, aluminum, aluminum oxide and carbon to a temperature of 1380.degree. C. at a total atmospheric pressure of less than or equal to 0.1 MPa in an atmosphere containing predominantly nitrogen and containing a concentration of 0 to 5 vol. % of carbon monoxide, subsequently increasing the concentration of carbon monoxide to between 10 and 30 vol. % and heating the molding to a temperature of 1500.degree. C. at a total atmospheric pressure of less than or equal to 0.1 MPa; and subsequently controlling the concentration of carbon monoxide to be between 0 and 10 vol. % and heating the molding to a temperature of 2200.degree. C. at a total atmospheric pressure of greater than or equal to 0.1 MPa.

Abstract: A sintered composite body of silicon nitride and silicon carbide is manufactured by mixing a silicon powder with a carbonaceous powder and a sintering additive, producing a mixture, molding the mixture into a molded body, heat-treating the molded body in an atmosphere containing a nitrogen gas for thereby simultaneously nitriding and carbonizing silicon contained in the molded body, and subsequently firing the molded body in a nitrogen gas atmosphere. A composite powder of silicon nitride and silicon carbide which is produced by simultaneously nitriding and carbonizing silicon contained in the molded body has a content of .alpha.-type silicon nitride which is at least 30% of all silicon nitride in the composite powder. To produce such a composite powder, a silicon powder is mixed with a carbonaceous powder and a sintering additive, producing a mixture, and the mixture is heat-treated in an atmosphere containing a nitrogen gas at a temperature of at most 1450.degree. C.