Abstract: A structure according to the embodiment includes a first crystal grain, a second crystal grain, and a first region. The first crystal grain includes silicon nitride. The second crystal grain includes a first element selected from a first group consisting of scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, aluminum, chromium, zirconium, magnesium, zinc, titanium, gallium, beryllium, calcium, strontium, barium, hafnium, vanadium, niobium, tantalum, tungsten, iron, cobalt, nickel, and copper, and oxygen. The first region includes an oxide of the first element.

Abstract: A ceramic contains, in mass percent: Si3N4: 20.0 to 60.0%, ZrO2: 25.0 to 70.0%, and one or more oxides selected from MgO, Y2O3, CeO2, CaO, HfO2, TiO2, Al2O3, SiO2, MoO3, CrO, CoO, ZnO, Ga2O3, Ta2O5, NiO, and V2O5: 5.0 to 15.0%. The ceramic has a coefficient of thermal expansion as high as that of silicon and an excellent mechanical strength, allows fine machining with high precision, and prevents particles from being produced.

Abstract: Described are multi-layer coatings, substrates (i.e., articles) coated with a multi-layer coating, and methods of preparing a multi-layer coating by atomic layer deposition, wherein the coating includes layers alumina and yttria.

Abstract: A tape casting slurry composition for preparing a silicon nitride sintered body is provided. The tape casting slurry composition exhibits a viscosity suitable for tape casting, and thus, can easily control the area and thickness of the prepared green sheet, thereby preparing a large area silicon nitride sintered body having a thickness of a circuit board without post-processing processes such as grinding, and the like. Therefore, according to the present invention, a silicon nitride sintered body can be prepared using low cost raw materials by a simplified process, thereby securing efficiency and economic feasibility of the preparation process.

Abstract: The spark plug includes an insulator formed of an alumina-based sintered body, and the insulator contains Si, Ba, and a rare earth element. In an analysis of the insulator by using a scanning transmission electron microscope having an electron-probe diameter of 1 nm, Si and a rare earth element are detected at a crystal grain boundary having a thickness of 15 nm or less, a content of an alkaline earth metal is less than a detection limit at the crystal grain boundary, and a diffraction spot is present in an electron diffraction pattern of a portion where Ba is detected.

Abstract: The present invention provides a silicon nitride wear resistant member comprising a silicon nitride sintered compact containing ?-Si3N4 crystal grains as a main component, 2 to 4% by mass of a rare earth element in terms of oxide, 2 to 6% by mass of Al in terms of oxide, and 0.1 to 5% by mass of Hf in terms of oxide, wherein the silicon nitride sintered compact has rare earth-Hf—O compound crystals; in an arbitrary section, an area ratio of the rare earth-Hf—O compound crystals in a grain boundary phase per unit area of 30 ?m×30 ?m is 5 to 50%; and variation of the area ratios of the rare earth-Hf—O compound crystals between the unit areas is 10% or less. Due to above structure, there can be provided a wear resistant member comprising the silicon nitride sintered compact having an excellent wear resistance and processability.

Abstract: A wear resistant member formed of ceramic sintered body mainly composed of silicon nitride, the ceramic sintered body containing 10 to 3500 ppm of an Fe component in terms of Fe element, more than 1000 ppm to 2000 ppm of a Ca component in terms of Ca element, and 1 to 2000 ppm of a Mg component in terms of Mg element, wherein a ?-phase ratio of silicon nitride crystal grains is 95% or more, a maximum longer diameter of the silicon nitride crystal grains is 40 ?m or less, Ca component existing in grain boundary phase is not detected by XRD (X-ray Diffraction method), and each of dispersions in Vickers hardness, fracture toughness and density of the wear resistant member is within a range of ±10%. According to this structure, there can be obtained a wear resistant member comprising a ceramic sintered body improved in grinding-work property in addition to an excellent wear resistant property.

Abstract: There is disclosed a porous material. The porous material contains aggregates, and a bonding material which bonds the aggregates to one another in a state where pores are formed among the aggregates, the bonding material contains crystalline cordierite, the bonding material further contains a rare earth element or a zirconium element, and a ratio of a mass of the bonding material to a total mass of the aggregates and the bonding material is from 12 to 45 mass %. The bonding material preferably contains, in the whole bonding material, 8.0 to 15.0 mass % of MgO, 30.0 to 60.0 mass % of Al2O3, 30.0 to 55.0 mass % of SiO2, and 1.5 to 10.0 mass % of a rare earth oxide or zirconium oxide.

Abstract: A process for preparing a ceramic body having a surface roughness, said process comprising the step of depositing particles of a ceramic material on the surface of a ceramic basic body. The process is characterized in that separate agglomerates comprising at least two particles and a binder binding the particles together are deposited on the surface of the basic body by projecting the agglomerates towards the basic body.

Abstract: There is disclosed a porous material containing aggregates; and a composite binding material which binds the aggregates to one another in a state where pores are formed and in which mullite particles that are reinforcing particles are dispersed in cordierite that is a binding material, and a content of metal silicon is smaller than 15 mass %. Preferably, to a total mass of the aggregates, the composite binding material and the metal silicon, a lower limit value of a content of the composite binding material is 12 mass %, and an upper limit value of the content of the composite binding material is 50 mass %. Preferably, to the total mass, a lower limit value of a content of the mullite particles is 0.5 mass %, and an upper limit value of the content of the mullite particles is 15 mass %. A porous material having a high thermal shock resistance is provided.

Abstract: The invention concerns a sintered ceramic component of silicon nitride or sialon suitable as rolling element in a bearing and a manufacturing method for making such ceramic components. The ceramic component has high density and a homogeneous and fine microstructure, giving the component excellent mechanical properties. Manufacturing of the sintered ceramic component by SPS is cost-effective and rapid.

Abstract: A composite article having a body including a first phase that includes a nitride material, a second phase that includes a carbide material, and a third phase having one of an amorphous phase material with a nitrogen content of at least about 1.6 wt % or an amorphous phase material comprising carbon.

Abstract: A silicon nitride material is disclosed which has properties necessary for efficient operation of a corona discharge igniter system in an internal combustion gas engine allowing an increase in fuel efficiency of over 10%. The material is disclosed in a range of compositions, all of which exhibit high dielectric strengths, high mechanical strength, thermal shock resistance and fracture toughness, low dielectric constant and loss tangent and electrical resistivity, all of which significantly increase the efficiency of the igniter system over current state of the art alumina insulators. Moreover, the materials retain their dielectric strength and structural integrity at elevated temperatures, up to 800° C.-1000° C. One embodiment comprises a sintered silicon nitride process comprising powder batching, binder removal and sintering. In the preferred embodiment the method of manufacture for silicon nitride is an SRBSN process comprising powder batching, powder pressing, binder removal, nitriding and sintering.

Abstract: Silicon nitride materials with high strength, fracture toughness values, and Weibull moduli simultaneously, due to unique large grain reinforcing microstructures and well engineered grain boundary compositions. The invention demonstrates that, surprisingly and contrary to prior art, a silicon nitride material can be made which simultaneously has high strength above about 850-900 MPa, a Weibull above about 15 and high fracture toughness (above about 8 and 9 MPa·m1/2), and has reinforcing grains longer than 5 ?m, typically longer than 10 ?m in the microstructure without compromising its properties and reliability. The product of this invention can be processed using a variety of densification methods, including gas-pressure sintering, hot pressing, hot isostatic pressing, but is not limited to these, and does not require multiple heat treatments for all of these features to be achieved.

Abstract: A silicon nitride sintered body, wherein in a silicon nitride substrate consisting of crystal grains of ?-type silicon nitride and a grain boundary phase containing at least one type of rare earth element (RE), magnesium (Mg) and silicon (Si), the grain boundary phase consists of an amorphous phase and a MgSiN2 crystal phase. The X-ray diffraction peak intensity of any crystal plane of a crystal phase containing the rare earth element (RE) is less than 0.0005 times the sum of the diffraction peak intensities of (110), (200), (101), (210), (201), (310), (320) and (002) of the crystal grains of the ?-type silicon nitride; and the X-ray diffraction peak intensity of (121) of the MgSiN2 crystal phase is 0.0005 to 0.003 times the sum of the X-ray diffraction peak intensities of (110), (200), (101), (210), (201), (310), (320) and (002) of the crystal grains of the ?-type silicon nitride.

Abstract: A sliding member includes a silicon nitride sintered compact containing a rare earth element of 7 to 18 mass % in terms of oxide and at least one element M selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W of 0.1 to 3 mass % in terms of oxide, and having a total content of impurity positive ion elements of 0.3 mass % or less and a thermal conductivity of 60 W/m·K or higher. The silicon nitride sintered compact includes silicon nitride crystal grains and a grain boundary phase, and has a ratio of crystalline compound phases in the grain boundary phase of 20% or more in area ratio, and an average grain size of the crystalline compound phases of 0.5 ?m or less. The sliding member is used, for example, as a bearing ball 2.

Abstract: A silicon nitride cutting tool comprising a sintered product is disclosed. The sintered product comprises silicon nitride, at least one rare earth element compound, and a magnesium compound. The silicon nitride cutting tool further comprises a surface region and an inside region comprising the sintered product with varying content ratios of component compounds to provide enhanced wear and fracture resistance.

Abstract: An insert includes a silicon nitride sintered body including ?-Si3N4 as a main component, Mg, and a rare-earth element Re (Y, La, Ce, Er, Dy, Yb). A content of Mg in terms of MgO is 1.0-7.0 mol %, a content of Re in terms of an oxide thereof is 0.4-1.0 mol %, and a total content of Mg and Re is from 1.7 to less than 7.5 mol %. The insert has a graded composition in which oxygen content increases from a surface of the sintered body toward an inside thereof such that 0.8-1.5 mass % of oxygen is contained in a region of less than 0.5 mm inside from the surface, 1.1-2.3 mass % of oxygen is contained in a region of 0.5 mm or more inside from the surface, and a difference in oxygen content between the regions is 0.1-1.0 mass %.

Abstract: A wear resistant member formed of silicon nitride sintered body having a volume of 4000 mm3 or more, the silicon nitride sintered body containing 1 to 5 mass % of a rare earth component in terms of rare earth element, 1 to 6 mass % of an Al component in terms of Al element, 10 to 3500 ppm of an Fe component in terms of Fe element, and 10 to 1000 ppm of a Ca component in terms of Ca element, wherein a ?-phase ratio of silicon nitride crystal grains is 95% or more, a maximum longer diameter of the silicon nitride crystal grains is 40 ?m or less, and each of dispersions in Vickers hardness and fracture toughness of an inner portion of the wear resistant member is within a range of ±10%. According to this structure, the wear resistant member can be manufactured with a low cost, and there can be provided a wear resistant member comprising a silicon nitride sintered body excellent in reliability and the dispersion in characteristics is effectively suppressed.

Abstract: Composite materials composed of cubic boron nitride (cBN) and a matrix component of various ceramic oxides, nitrides, and solid solutions of matrix materials as well as whisker reinforcements. Methods of manufacture and their use in high performance machining of ferrous metals are also claimed and disclosed.

Abstract: A silicon nitride sintered compact contains silicon nitride grains, and a sintering aid component in a range of 2 to 15 mass %. The silicon nitride grains include needle crystal grains each having a long diameter L of 10 ?m or less and a ratio (L/S) of the long diameter L to a short diameter S of 5 or more, by 50% or more in area ratio in a crystalline structure of the silicon nitride sintered compact. The silicon nitride sintered compact is used as a sliding member like a bearing ball (2).

Abstract: A densified silicon nitride body can be formed using a lanthana-based sintering aid. The composition may exhibit properties that provide a material useful in a variety of applications that can benefit from improved wear characteristics. The composition may be densified by sintering and hot isostatic pressing.

Abstract: A silicon nitride-melilite composite sintered body in accordance with the invention includes silicon nitride and a melilite Me2Si3O3N4, where Me denotes a metal element combining with silicon nitride to generate the melilite. The silicon nitride-melilite composite sintered body contains Si in a range of 41 to 83 mole percent in Si3N4 equivalent and Me in a range of 13 to 50 mole percent in oxide equivalent. The silicon nitride-melilite composite sintered body has an average thermal expansion coefficient that is arbitrarily adjustable in a range of 2 to 6 ppm/K at temperatures of 23 to 150° C. The silicon nitride-melilite composite sintered body has a high Young's modulus, a high mechanical strength, and excellent sintering performance. A device used for inspection of semiconductor in accordance with the invention utilizes such a silicon nitride-melilite composite sintered body.

Abstract: The invention concerns a sintered ceramic component of silicon nitride or sialon suitable as rolling element in a bearing and a manufacturing method for making such ceramic components. The ceramic component has high density and a homogeneous and fine microstructure, giving the component excellent mechanical properties. Manufacturing of the sintered ceramic component by SPS is cost-effective and rapid.

Abstract: A high-strength, fracture-resistant silicon nitride ceramic material that includes about 5 to about 75 wt-% of elongated reinforcing grains of beta-silicon nitride, about 20 to about 95 wt-% of fine grains of beta-silicon nitride, wherein the fine grains have a major axis of less than about 1 micron; and about 1 to about 15 wt-% of an amorphous intergranular phase comprising Si, N, O, a rare earth element and a secondary densification element. The elongated reinforcing grains have an aspect ratio of 2:1 or greater and a major axis measuring about 1 micron or greater. The elongated reinforcing grains are essentially isotropically oriented within the ceramic microstructure. The silicon nitride ceramic exhibits a room temperature flexure strength of 1,000 MPa or greater and a fracture toughness of 9 MPa-m(1/2) or greater. The silicon nitride ceramic exhibits a peak strength of 800 MPa or greater at 1200 degrees C.

Abstract: High-volume, fully dense, multi-component monoliths with microstructurally indistinguishable joints that can be used as refractory, corrosion and wear resistant components in the non-ferrous metal industry. The Si3N4 monoliths according to the invention comprise at least 90% by weight ?-type Si3N4 and up to 10% by weight of a predominantly amorphous binder phase, said binder phase being formed from compositions of the rare earth metal —Al—Si—O—N, rare earth metal —Mg—Si—O—N or Mg—Si—O—N systems. Preferably the rare earth metal is yttrium (Y). The monoliths have a volume of greater than 250 cm3. A method of making the multi-component monoliths is achieved by simultaneously joining and uniaxially hot pressing an assembly of reaction bonded silicon nitride bodies (RBSN bodies). RBSN bodies are placed in contact with each other in the substantial absence of any interlayer or ceramic paste in between.

Abstract: A coated material for a cutting tool can realize long life-time under severe cutting processing conditions such as high-speed processing, high-feed-rate processing, higher hardness of a material to be cut, cutting of a difficult-to-cut material, etc. In a coated material in which a coating is coated on the surface of a substrate, at least one layer of the coating is a hard film having a cubic metallic compound which includes at least one metal element M selected from Al, Si, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W, and at least one element selected from C, N and O. An X-ray intensity distribution of an ? axis in a pole figure for a (111) plane of the hard film has a maximum intensity in an ? angle range of 75 to 90°, and an X-ray intensity distribution of an ? axis in a pole figure for a (220) plane of the hard film has a maximum intensity in an ? angle range of 75 to 90°.

Abstract: Disclosed is a porous sintered reaction-bonded silicon nitride ceramic, which includes an array of sintered granules having fine pore channels in the sintered granules and coarse pore channels formed between the sintered granules, and in which the pore channel size is controlled so that both coarse pores and fine pores are formed together in the ceramic, thus simultaneously enhancing air permeability and capturing efficiency. A method of manufacturing the porous sintered reaction-bonded silicon nitride ceramic is also provided.

Abstract: A precursor of a ceramic adhesive suitable for use in a vacuum, thermal, and microgravity environment. The precursor of the ceramic adhesive includes a silicon-based, preceramic polymer and at least one ceramic powder selected from the group consisting of aluminum oxide, aluminum nitride, boron carbide, boron oxide, boron nitride, hafnium boride, hafnium carbide, hafnium oxide, lithium aluminate, molybdenum silicide, niobium carbide, niobium nitride, silicon boride, silicon carbide, silicon oxide, silicon nitride, tin oxide, tantalum boride, tantalum carbide, tantalum oxide, tantalum nitride, titanium boride, titanium carbide, titanium oxide, titanium nitride, yttrium oxide, zirconium boride, zirconium carbide, zirconium oxide, and zirconium silicate. Methods of forming the ceramic adhesive and of repairing a substrate in a vacuum and microgravity environment are also disclosed, as is a substrate repaired with the ceramic adhesive.

Abstract: It is intended to provide a taphole mix capable of forming SiC bonds with minimum of an excess and a deficiency in components thereof, and excellent in drillability. A fine particle fraction having a particle diameter of 75 ?m or less is comprised of three components consisting of a silicon nitride-based material, a carbon-based material, and roseki, or comprised of the three component, and one or more selected from the group consisting of an alumina-based material, a silicon carbide-based material, a rare-earth element oxide-based material, clay, a high-purity silica-based material containing SiO2 in an amount of 80 mass % or more, a boron compound-based material in an amount of less than 0.3 mass % with respect to 100 mass % of the silicon nitride-based material, and a metal powder in an amount of less than 10 mass % with respect to 100 mass % of the carbon-based material.

Abstract: A ceramic material for an optical member which shows black, wherein the ceramic material comprises a reaction-sintered sintered ceramic body prepared by synthesizing a formed body of a mixture comprising a ceramic raw material and a component that accelerates blackening, making use of a reaction sintering; and wherein the ceramic material is a porous body.

Abstract: A sintered product of silicon nitride includes a crystal phase mainly having silicon nitride crystal grains and an amorphous grain-boundary phase located on the grain boundaries of the silicon nitride crystal grains. The grain-boundary phase contains lanthanum, aluminum, magnesium, silicon, and oxygen. The sintered product described above contains 0.1% by mass or more of lanthanum on an oxide basis, 0.05 to 0.6% by mass of aluminum on an oxide basis, 0.3% by mass or more of magnesium on an oxide basis, and 2.5% by mass or less of oxygen. The total amount of lanthanum on an oxide basis, aluminum on an oxide basis, and magnesium on an oxide basis is 3.5% by mass or less.

Abstract: A silicon nitride sintered compact contains silicon nitride grains, and a sintering aid component in a range of 2 to 15 mass %. The silicon nitride grains include needle crystal grains each having a long diameter L of 10 ?m or less and a ratio (L/S) of the long diameter L to a short diameter S of 5 or more, by 50% or more in area ratio in a crystalline structure of the silicon nitride sintered compact. The silicon nitride sintered compact is used as a sliding member like a bearing ball (2).

Abstract: A composition and method for fabricating high-density Ta—Al—O, Ta—Si—N, and W—Si—N sputtering targets, having particular usefulness for the sputtering of heater layers for ink jet printers. Compositions in accordance with the invention comprise a metal component, Si3N4, and a sintering aid so that the targets will successfully sputter without cracking, etc. The components are combined in powder form and pressure consolidated under heated conditions for a time sufficient to form a consolidated blend having an actual density of greater that about 95% of the theoretical density. The consolidated blend may then be machined so as to provide the final desired target shape.

Abstract: A precursor of a ceramic adhesive suitable for use in a vacuum, thermal, and microgravity environment. The precursor of the ceramic adhesive includes a silicon-based, preceramic polymer and at least one ceramic powder selected from the group consisting of aluminum oxide, aluminum nitride, boron carbide, boron oxide, boron nitride, hafnium boride, hafnium carbide, hafnium oxide, lithium aluminate, molybdenum silicide, niobium carbide, niobium nitride, silicon boride, silicon carbide, silicon oxide, silicon nitride, tin oxide, tantalum boride, tantalum carbide, tantalum oxide, tantalum nitride, titanium boride, titanium carbide, titanium oxide, titanium nitride, yttrium oxide, zirconium diboride, zirconium carbide, zirconium oxide, and zirconium silicate. Methods of forming the ceramic adhesive and of repairing a substrate in a vacuum and microgravity environment are also disclosed, as is a substrate repaired with the ceramic adhesive.

Abstract: To provide a sintered silicon nitride with conductivity and densification, an oxide of titanium group elements, such as titanium oxide, hafnium oxide, zirconium oxide and the like, aluminum oxide and/or aluminum nitride is added as needed to silicon nitride-oxidant of rare-earth elements-aluminum oxide system or silicon nitride-oxide of rare-earth elements-magnesia system, and then specified quantity of carbon nonotube (CNT) is added to the above mixture. CNT generates silicon carbide after the reaction with contiguous or proximal silicon nitride and the like depending on the sintering duration at high temperature. Since silicon carbide is generated along with nanotubes, the silicon carbide functions as conductor with excellent heat resistance, corrosion resistance and the like.

Abstract: The present invention provides methods for making a microporous ceramic material using a metal silicon powder and including a reaction sintering process of the silicon. A material for forming a microporous ceramic material used in these methods includes a metal silicon powder, a silicon nitride powder and/or a silicon carbide powder, and if desired, a yttrium oxide powder and/or an aluminum oxide powder. These methods can make a microporous ceramic material that can be used preferably as a gas or liquid filter, a catalyst carrier or a support of a gas separation membrane.

Abstract: A silicon nitride abrasion resistant member is formed of silicon nitride sintered body containing 2% to 4% by mass of a rare earth element in terms of oxide thereof as a sintering aid, 2% to 6% by mass of an Al component in terms of oxide thereof, and 2% to 7% by mass of silicon carbide. The silicon nitride sintered body has a porosity of 1% or less, a three-point bending strength of 800 to 1000 MPa, and a fracture toughness of 5.7 to 6.5 MPa·m1/2. According to this structure, even when an inexpensive silicon nitride powder manufactured by metal nitriding method is used, there can be provided a silicon nitride abrasion resistant member having a mechanical strength, high abrasion resistance, and a rolling life, equal to or higher than those of conventional silicon nitride sintered bodies, and excellent workability, and a method for manufacturing the member can be provided.

Abstract: A nitride glass with the general formula ?x?y?z is provided wherein ? is a glass modifier comprising at least one electropositive element. ? comprises Si, B, Ge, a and/or Al. ? is N or N together with O, whereby the atomic ratio of O:N is in the interval from 65:35 to 0:100.

Abstract: A silicon nitride-bonded SiC refractory is provided, which includes SiC as a main phase and Si3N4 and/or Si2N2O as a secondary phase and which has a bending strength of 150 to 300 MPa and a bulk density of 2.6 to 2.9. A method for producing a silicon nitride-bonded SiC refractory is also provided, which comprises a step of mixing 30 to 70% by mass of a SiC powder of 30 to 300 ?m as an aggregate, 10 to 50% by mass of a SiC powder of 0.05 to 30 ?m, 10 to 30% by mass of a Si powder of 0.05 to 30 ?m, and 0.1 to 3% by mass, in terms of oxide, of at least one member selected from the group consisting of Al, Ca, Fe, Ti, Zr and Mg.

Abstract: High-volume, fully dense, multi-component monoliths with microstructurally indistinguishable joints that can be used as refractory, corrosion and wear resistant components in the non-ferrous metal industry. The Si3N4 monoliths according to the invention comprise at least 90% by weight ?-type Si3N4 and up to 10% by weight of a predominantly amorphous binder phase, said binder phase being formed from compositions of the rare earth metal —Al—Si—O—N, rare earth metal —Mg—Si—O—N or Mg—Si—O—N systems. Preferably the rare earth metal is yttrium (Y). The monoliths have a volume of greater than 250 cm3. A method of making the multi-component monoliths is achieved by simultaneously joining and uniaxially hot pressing an assembly of reaction bonded silicon nitride bodies (RBSN bodies). RBSN bodies are placed in contact with each other in the substantial absence of any interlayer or ceramic paste in between.

Abstract: The present invention provides silicon nitride with tungsten carbide additives in a sinterable material comprising silicon nitride and tungsten carbide, in which the silicon nitride content is a minimum of about 80% and wherein the total nitride component is about 28-40 w/w % N2, and further comprising about 1.5-3.5 w/w % Al, about 2-6 w/w % Y, about 1.5-7 w/w % W, and about 3-9 w/w % O2. which after sintering will produce ceramic bodies with a high degree of toughness suitable for armor applications.

Abstract: A yttria sintered body is provided which includes yttria as a principal ingredient and 5 to 40 vol. % silicon nitride, and which exhibits enhanced corrosion resistance and mechanical strength.

Abstract: A sintered ceramic material comprises a crystalline phase and an intergranular phase comprising a glass phase. The material is manufactured from a starting powder being mixed with an additive comprising one or more metal from a group of Li, Na, Mg, Ca, Sr, Ba, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Th, Pa or U. The additive is in non oxide form, or in a form which transforms to a metal or nitride during a synthesis in nitrogen atmosphere and the resulting glass phase having a high nitrogen content with a N:O ratio higher than 35:65 and a glass transition temperature above 950° C.

Abstract: The present invention is directed to bearings produced from a silicon nitride material. The silicon nitride material consists of a sintering aid selected from the group consisting of Al2O3 and Y2O3, silicon dioxide, and optionally, up to 10 mole %, based on the amount of silicon nitride, of an additive that reacts with silicon nitride, said additive selected from the group consisting of TiO2, WO3, MoO3 and mixtures thereof.

Abstract: In hexaboride particles having particles of a hexaboride of at least one element (X) selected from Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sr and Ca, or a dispersion of such particles, the surfaces of the hexaboride particles have physically been coated with a surface treatment agent containing silicon, selected from a silazane type treatment agent, a chlorosilane type treatment agent, an inorganic treatment agent having at least one alkoxyl group in the molecular structure, and an organic treatment agent having at least one alkoxyl group at a molecular terminal or in the side chain, or have been coated with the surface treatment agent, having chemically combined with hexaboride particles on the surfaces of the hexaboride particles.

Abstract: A silicon nitride sintered body exhibiting a high heat conductivity, the silicon nitride sintered body includes a rare earth element in an amount of 2 to 17.5 mass % in terms of the oxide thereof, Fe in an amount of 0.07 to 0.5 mass % in terms of the oxide thereof, Ca in an amount of 0.07 to 0.5 mass % in terms of the oxide thereof, Al in an amount of 0.1 to 0.6 mass % in terms of the oxide thereof, Mg in an amount of 0.3 to 4 mass % in terms of the oxide thereof, and Hf in an amount not larger than 5 mass % (including 0 mass %) in terms of the oxide thereof.

Abstract: A silicon nitride based ceramic, that is highly effective for use as a cutting tool for the high speed machining of cast irons, that is essentially a homogeneous mixture consisting of both crystalline and whisker forms of beta silicon nitride that are interstitially bonded by a stoichiometrically balanced glass mixture of magnesia, silica, yttria and zirconia, where the ratios of each have been controlled to increase the eutectic point and refractoriness of the mixed glass.

Abstract: The present invention consists of a synergistic mixture of Si3N4, Al2O3, AlN, SiO2 and Nd2O3. The cost effective synergistic composition is useful for the preparation of dense neodymium stabilised ?-Si3N4-?-SiAlON composite of the order of >98% theoretical density, having high hardness and high fracture toughness. The dense ?-Si3N4-?-SiAlON composite will be useful for low temperature applications as wear parts like bearing and roller materials and particularly for grinding and milling operations like grinding balls.

Abstract: The present invention provides a process for the manufacture of dense neodymium stabilized ?-Si3N4-?-SiAlON composite, wherein a synergistic composition essentially consisting of Si3N4, Al2O3, AlN, SiO2 and Nd2O3 as starting materials is mixed in proportion to make a total of 100 mole in the mixed batch, passing the powder through 100 mesh, pressing the powder to form green compacts, sintering the green compacts at a temperature in the range of 1700° to 1900° C. in nitrogen atmosphere. The process of the present invention provides neodymium stabilized ?-Si3N4-?-SiAlON composites by processing a composition from the system Si3N4—Al2O3.AlN—Nd2O3.9AlN—SiO2 resulting into dense product of the order of >98% theoretical density with the advantages such as cost effectiveness, high hardness and high fracture toughness.