Abstract: Methods of making and compositions of dense sintered ceramic nano- and micro-composite materials that are highly stable in a variety of conditions and exhibit superior toughness and strength. Liquid feed flame spray pyrolysis techniques form a plurality of nanoparticles (e.g., powder), each having a core region including a first metal oxide composition comprising Ce and/or Zr or other metals and a shell region including a second metal oxide composition comprising Al or other metals. In certain aspects, the core region comprises a partially stabilized tetragonal ZrO2 and the shell region comprises an ?-Al2O3 phase. The average actual density of the ceramic after sintering is greater than 50% and up to or exceeding 90% of a theoretical density of the ceramic.

Abstract: A ceramic porous body including at least Si as a chemical component, the ceramic porous body being obtained by adding a porous silica powder or a porous silica-containing compound powder to a forming raw material to prepare a clay, forming the resulting ceramic clay into a specific shape, and firing the formed product. The ceramic porous body according to the present invention does not produce carbon dioxide or toxic gas during firing and allows the firing time to be reduced in comparison with the case of using a resin powder or a carbon powder as a pore-forming agent by using the porous silica powder or the porous silica-containing compound powder as the pore-forming agent during production. Moreover, a change in pore-forming characteristics or deformation of a formed product rarely occurs.

Abstract: A ceramic foam filter for molten aluminum alloys comprising an alumina silicate rich core and a boron glass shell and a chemical composition comprising: 20-70 wt % Al2O3, 20-60 wt % SiO2, 0-10 wt % CaO, 0-10 wt %; MgO and 2-20 wt % B2O3.

Abstract: A chemical processing apparatus that utilizes a ceramic media sintered at a lower temperature than the apparatus' maximum exposure temperature is described. The media's physical and chemical properties may contribute to its thermal stability when exposed to temperatures that exceed the media's sintering temperature by at least 50° C.

Abstract: A process for producing a honeycomb structure by obtaining clay from a cordierite-forming raw material containing an alumina source, a silica source, and a magnesia source; and forming the clay into a honeycomb shape, wherein a material having, in its volume particle size distribution, a 50 volume % particle size (V50) [?m] of 1 to 25 ?m is used, as each of alumina source, silica source, and magnesia source; and a material having, in the volume particle size distribution of the whole cordierite-forming raw material, a ratio of 90 volume % particle size (Vall90) [?m] to 10 volume % particle size (Vall10) [?m] [a volume particle size distribution ratio (Vall90/Vall10)] of 10 or less and a difference (Vall90?Vall10) between 90 volume % particle size (Vall90) [?m] and 10 volume % particle size (Vall10) [?m] of 25 ?m or less is used, as the cordierite-forming raw material.

Abstract: An aluminum oxide sintered product including a layer phase containing a rare-earth element and fluorine among grains of aluminum oxide serving as a main component, or a phase containing a rare-earth element and fluorine along edges of grains of aluminum oxide serving as a main component. The product includes a phase containing a rare-earth element and a fluorine element among grains of aluminum oxide, the phase not being in the form of localized dots but in the form of line segments, when viewed in an SEM image. The product can be readily adjusted to have a volume resistivity in the range of 1×1013 to 1×1016 ?·cm, the volume resistivity being calculated from a current value after the lapse of 1 minute from the application of a voltage of 2 kV/mm to the aluminum oxide sintered product at room temperature.

Abstract: The invention relates to a fired refractory ceramic product. According to the invention, this generic term encompasses both shaped and unshaped products. Shaped products are ones which have a defined shape so that they can be manufactured in finished form on the premises of the manufacturer. Shaped products include: bricks, nozzles, tubes, stoppers, plates, etc. The term unshaped products includes ones which are usually produced by the user from a corresponding composition. They include bases for furnaces which are cast from a composition but also repair compositions, etc.

Abstract: The invention relates to a fired, basic, refractory, industrial ceramic shaped body comprising at least one basic resistor component and an elasticizer component, wherein the elasticizer component is a calcium aluminate having the abbreviated formula CA6. The invention additionally relates to a process for producing the shaped body and to its use.

Abstract: A ceramic body, a ceramic catalyst body, a ceramic catalyst body and related manufacturing methods are disclosed wherein a cordierite porous base material has a surface, formed with acicular particles made of a component different from that of cordierite porous base material, which has an increased specific surface area with high resistance to a sintering effect. The ceramic body is manufactured by preparing a slurry containing an acicular particle source material, preparing a porous base material, applying the slurry onto a surface of the porous base material and firing the porous base material, whose surface is coated with the slurry, to cause acicular particles to develop on the surface of the porous base material. A part of or a whole of surfaces of the acicular particles is coated with a constituent element different from that of the acicular particles.

Abstract: Molten ceramic grains are intended, for example, for applications involving abrading tools, having the following average chemical weight composition, expressed in weight percent based on oxide content: Al2O3: 93% to 97.5%; MgO: 2.2 to 6.5%; SiO2: <0.1%; other impurities: <0.4%.

Abstract: The present invention provides materials and methods for the manufacture of high porosity ceramic exhaust filters employing relatively low amounts of pore formers, the filters combining efficient diesel particulate filtration with effective support for exhaust emissions control catalysts. Cordierite-forming ceramic batches comprising non-hydrated transition alumina powders of relatively large particle size provide high porosities with well-controlled pore sizes and with low filter thermal expansion coefficients and good mechanical strengths.

Abstract: A ceramic having at least about 90% by weight magnesium aluminate and having a bulk scattering and absorption loss of less than about 1/cm at any wavelength in a range of about 0.23 to about 5.3 microns or 0.2/cm at any wavelength in a range of about 0.27 to about 4.5 microns. A method of making a ceramic by providing a plurality of particles having a magnesium aluminate core and a fluoride salt coating; heating the particles in an oxidizing atmosphere to a temperature in the range of about 400° C. to about 750° C.; and sintering the particles to form a solid ceramic.

Abstract: There is provided a honeycomb structured body having improved durability in a honeycomb structure body obtained by unitarily bonding a plurality of honeycomb segments. There is provided a honeycomb structure body 1 including a plurality of honeycomb segments 12 each having an outer wall 7, partition walls 2 disposed in the outer wall 7, and a plurality of cells 3 separated from each other by the partition walls 2 and extending in an axial direction, a bonding layer 8 interposed between the plurality of honeycomb segments 12 to unitarily bond the honeycomb segments 12, and an intermediate layer 9 interposed between the bonding layer 8 and the honeycomb segments 9. In the honeycomb structure body 1, pores having a diameter of 0.5 ?m or more of the intermediate layer 9 occupies 25% by volume or less of the whole volume of the intermediate layer 9.

Abstract: The present invention is directed to a noise suppressor for electronic signals. The noise suppressor at least includes Aluminum Oxide (Al2O3) that is sintered under high temperature, resulting in ceramic Aluminum Oxide (Al2O3) for effectively absorbing or suppressing noise, and reshaping the waveform or filtering waveform glitch of the electronic signals.

Abstract: According to the present invention, a porous material is characterized by comprising: a connected structure formed by combining silicon carbide which is an aggregate with cordierite which is a combining material in a state to hold a large number of pores, and having a porosity of 52 to 70% and a median pore diameter of 15 to 30 ?m, and is a porous material having a high porosity and a high strength and having a remarkably low possibility of including defective portions such as cuts and the like causing liquid leakage in a case where the material is used as a filter.

Abstract: The present invention is directed to a noise suppressor for electronic signals. The noise suppressor at least includes Aluminum Oxide (Al2O3) that is sintered under high temperature, resulting in ceramic Aluminum Oxide (Al2O3) for effectively absorbing or suppressing noise, and reshaping the waveform or filtering waveform glitch of the electronic signals.

Abstract: Disclosed is a corrosion resistant member comprising a sintered material having an ?-Al2O3 crystal and an YAG (yttrium-aluminum-garnet) crystal. The corrosion resistant member contains metal elements, 70 to 98% by mass (inclusive) of Al in terms of Al2O3 and 2 to 30% by mass of Y in terms of Y2O3. The corrosion resistant member has a peak intensity ratio I116/I104 within the range from 0.94 to 1.98, preferably. 2.21 or higher, wherein I116 and I104 represent peak intensities attributed to the (116) face and the (104) face, respectively, of an ?-Al2O3 crystal as measured by X-ray diffractometry on its surface layer.

Abstract: The proposed inventions pertain to technology of continuous inorganic fibers manufacturing by way of drawing from melted minerals. Such continuous inorganic fibers may be used in production of heat-resistant threads, rovings, cut fibers, fabrics, composition materials and products based on such materials. The C contains the mixture of silicon (SiO2), aluminum (Al2O3), titan (TiO2), iron (Fe2O3 and FeO), calcium (CaO), magnesium (MgO), manganese (MnO) oxides and admixtures, and, according to the invention, this composition further contains potassium (K2O), sodium (Na2O), barium (BaO) oxides with the following components ratio (in mass %): Al2O3 15.90-18.10 TiO2 0.75-1.20 Fe2O3 + FeO 7.51-9.53 CaO 6.41-8.95 MgO 2.50-6.40 K2O 1.60-2.72 Na2O 3.30-4.10 P2O5 0.23-0.50 SO3 0.02-0.15 MnO 0.12-0.21 BaO 0.05-0.19 admixtures, up to 1.00 SiO2 the rest.

Abstract: A method of the controlling the chemical and physical characteristics of a body formed from a powder precursor, including measuring a predetermined amount of a first particulate precursor material, wherein the first particulate precursor material defines a plurality of respective generally spherical first phase particles, adhering second phase particles to the respective first phase particles to define composite particles, forming the composite particles into a green body, and heating the green body to yield a fired body. The second phase particles adhered to the first phase particles are substantially uniformly distributed and a respective first phase particle defines a first particle diameter that is at least about 10 times larger than the second phase diameter defined by a respective second phase particle. The composite particles define a predetermined composition.

Abstract: There is disclosed a ceramic clay obtained by kneading a forming material containing a ceramic forming material, wherein the forming material contains layered double hydroxide, in addition to the ceramic forming material, at a ratio of 0.5 to 50% by mass with respect to a total with the ceramic forming material, and hardness measured by an NGK clay hardness meter is set to 4 to 18 mm. A high-strength honeycomb structure can be obtained capable of preventing or inhibiting pollution and global warming when used in manufacturing a ceramic structure, and having few defects such as cracks.

Abstract: The present invention provides a cordierite ceramic containing at least either of zirconium oxide and hafnium oxide and also containing titanium oxide, wherein the molar ratio of zirconium (Zr), hafnium (Hf) and titanium (Ti) in terms of the moles in the form of the dioxides, respectively which is given by the formula [(ZrO2+HfO2)/TiO2] is in a range of 0.1 to 5; and a honeycomb structure made of the cordierite ceramic. In this cordierite ceramic, the phases of the above components are contained mainly as zirconium titanate or hafnium titanate, and there occurs no heterogeneity in appearance, caused by change in color and generation of spots or the like.

Abstract: A chemical processing apparatus that utilizes a ceramic media sintered at a lower temperature than the apparatus' maximum exposure temperature is described. The media's physical and chemical properties may contribute to its thermal stability when exposed to temperatures that exceed the media's sintering temperature by at least 50° C.

Abstract: The invention relates to a melted and cast refractory product which is intended, for example, for a checker work element of a glass furnace regenerator, having the following average chemical weight composition, expressed in weight percent based on oxide content: 0.4%<MgO<2.5%; 0.2%<SIO2<2%; CaO<0.4%; impurities<0.5% AL2O3: complement.

Abstract: Cordierite ceramic articles with high volume percent porosities of at least 64% but less than 80% have controlled median pore sizes and mean coefficients of thermal expansion that impart substantially improved modulus of rupture strengths (MOR) and thermal shock resistance (TSR) to the ceramic articles.

Abstract: A process for making cordierite ceramic articles exhibiting improved properties involves steps of preparing a solution in which a sintering promoting agent is dissolved in a solvent prior to being combined with an alumina source, a silica source, a magnesia source, and an organic binder. The sintering promoting agent induces rapid growth of cordierite at lower temperatures and/or during shorter firing times, while preserving valued CTE and MOR properties. Improved MOR (MOR/E?mod*CTE) provide products exhibiting higher thermal shock resistance, and improved pore size distribution with cut off of smaller pore sizes providing products with lower back pressure at high filtration efficiency.

Abstract: Disclosed is a sintered ceramic article that exhibits a primary crystalline phase of cordierite having an analytical oxide composition, expressed in weight percent on an oxide basis, of 49-53% SiO2, 33-38% Al2O3, 12-16% MgO and which exhibits a coefficient of thermal expansion equal to or more negative than ?0.6×10?7/° C. over the temperature range of about 25° C. to about 800° C. Also disclosed is a method for producing a ceramic article comprising the aforementioned cordierite.

Abstract: In a method of producing a cordierite honeycomb structure body, talc, kaolin, and alumina as prepared raw materials are mixed. The mixed raw materials are extruded and molded in an extrusion molding step. The obtained green body is cut into plural green bodies of a specified length. In a following drying step, the green body is dried and then fired in order to make the cordierite honeycomb structure body. In particular, the talc for use in the mixing step has IgLoss (Ignition Loss) within a range of 5.7 to 6.5 wt % which is obtained by firing at 1,000° C. for two hours.

Abstract: A method of manufacturing a cordierite porous body of the present invention is a method of manufacturing the cordierite porous body using a cordierite forming material including an Al source, an Si source, and an Mg source and forming cordierite by firing, characterized in that an inorganic micro balloon containing SiO2 and Al2O3 is used as a part or all of the Al source and the Si source, so that a high-open-porosity cordierite porous body having an extremely low possibility of generating defects causing leakage of a fluid, such as cuts can be manufactured.

Abstract: A dense cordierite based sintered body is provided, containing at least 93% by mass of cordierite among crystal components present in the sintered body. The average particle diameter of the particles constituting the sintered body is 2 ?m or less.

Abstract: A cordierite ceramic body having (i) a pore size distribution and a porosity which satisfy the relationship 10.2474/[(d50)2(pore fraction)]+0.0366183(d90)?0.00040119(d90)2+0.468815(1/pore fraction)2+0.0297715(d50)+1.61639(d50?d10)/d50?3.65, and (ii) a CTE (25°-800° C.) of ?15×10?7/° C., wherein the cordierite ceramic body is produced from a moldable mixture comprising cordierite-forming raw materials including (a) a fine talc having a median particle diameter, as measured by laser diffraction, of less than 10 micrometers, and a B.E.T. specific surface area of greater than 5 m2/g, and (b) a pore former. The cordierite ceramic body is suitable in the fabrication of cellular, wall-flow diesel particulate filters having a low pressure drop, high filtration efficiency and improved strength.

Abstract: A fired spinel complex oxide is produced by firing a mixture containing a slag by-produced in chromium refining, a reducer, and a silica-containing material, and is essentially composed of: 29 to 40 percent by weight of Fe2O3; 15 to 20 percent by weight of Al2O3; 9 to 14 percent by weight of MgO; 0 to 4 percent by weight of Na2O; 9 to 17 percent by weight of Cr2O3; 14 to 20 percent by weight of SiO2; and 2 percent by weight or less of CaO. The fired spinel complex oxide shows a Cu—K&agr; X-ray diffraction pattern in which the ratio (b/a) of the diffraction peak intensity of the silica-containing material (b) in the vicinity of 2&thgr;=26.7° to the {113} plane diffraction peak intensity (a) in the vicinity of 2&thgr;=36° is 0.1 or less.

Abstract: A ceramics structure body having chemical composition of 42 to 56 wt % of SiO2, 30 to 45 wt % of Al2O3 and 12 to 16 wt % of MgO, crystalline phase mainly composed of cordierite, a porosity of 55 to 65%, an average pore size of 15 to 30 &mgr;m; and the total area of pores exposed on surfaces of partition walls constituting the honeycomb ceramics structure body being 35% or more of the total area of partition wall surfaces. Fifteen to 25 wt % of graphite and 5 to 15 wt % of a synthetic resin are added as a pore forming agent to a cordierite-forming raw material; the resultant is kneaded and molded into a honeycomb shape; and the resultant is dried and fired to produce above-mentioned honeycomb ceramics structure body. According to this honeycomb ceramics structure body, a low pressure loss and a high collection efficiency can be attained.

Abstract: A ceramic carrier comprising a substrate ceramic containing Mg, Al, Si and O as constituent elements and containing, as the second component, an element other than said constituent elements. The support contains many microvoids capable of absorbing thermal expansion, the porosity is larger than 28%, and the thermal expansion coefficient is smaller than 2.3×10−6/° C. The second component enables the direct loading of a catalytic component.

Abstract: An economical and environment-friendly process for the synthesis of anionic clays with carbonate and/or hydroxide anions as the charge-balancing interlayer species is disclosed. The process involves reacting a slurry comprising an aluminum source and a magnesium source, the aluminum source comprising two types of aluminum-containing compounds, preferably aluminum trihydrate and/or thermally treated calcined aluminum trihydrate. There is no necessity to wash or filter the product. It can be spray dried directly to form microspheres or can be extruded to form shaped bodies. The product can be combined with other ingredients in the manufacture of catalysts, absorbents, pharmaceuticals, cosmetics, detergents, and other commodity products.

Abstract: A particulate sealant for forming plugs in selected cells of honeycomb structures and consisting essentially, by weight, of about 70 to 90% ceramic blend, the ceramic blend being raw ceramic materials selected to form a composition consisting essentially of in percent by weight about 12 to 16% MgO, about 33 to 38% Al2O3, and about 49 to 54% SiO2, which will form cordierite (2MgO.2Al2O3.5SiO2) on firing, and about 10 to 30% binder system comprising a thermoplastic polymer capable of forming a gel or a thermosetting resin.

Abstract: Ceramic mass and thermal transfer media suitable for use in thermal regenerative oxidizers made using a mixture of a ball clay, talc and optionally a dolomitic limestone have enhanced resistance to environments containing halogens and hydrogen halides. The media preferably comprises less than 0.25% by weight of alkali metal, expressed as the oxide, and has a cordierite: silica phase ratio of less than 1.2:1, as determined by X-ray diffraction.

Abstract: A cordierite ceramic body having (i) a pore size distribution and a porosity which satisfy the relationship 10.2474/[(d50)2(pore fraction)]+0.0366183(d90)−0.00040119(d90)2+0.468815(1/pore fraction)2+0.0297715(d50)+1.61 639(d50−d10)/d50≦3.65, and (ii) a CTE (25°-800° C.) of ≦15×10−7/° C., wherein the cordierite ceramic body is produced from a moldable mixture comprising cordierite-forming raw materials including (a) a fine talc having a median particle diameter, as measured by laser diffraction, of less than 10 micrometers, and a B.E.T. specific surface area of greater than 5 m2/g, and (b) a pore former. The cordierite ceramic body is suitable in the fabrication of cellular, wall-flow diesel particulate filters having a low pressure drop, high filtration efficiency and improved strength.

Abstract: Disclosed is a ceramic material which is suitable for coating a body by way of a thermal spraying method and which has a coefficient of longitudinal thermal expansion that may be matched to that of a metal. The ceramic material includes 10 to 95% by weight of MgAl2O4, 5 to 90% by weight of MgO, up to 20% by weight of Al2O3, remainder standard impurities, and has grains of MgO which are embedded in a matrix of MgAl2O4.

Abstract: A ceramic filter for trapping and combusting diesel exhaust particulates composed of an end-plugged cordierite honeycomb structure exhibiting a pore size distribution as determined by mercury porosimetry in which the quantity d50/(d50+d90) as related to pore size distribution is less than 0.70, a soot loaded permeability factor Sf, as defined by the equation [d50/(d50+d90)]/[% porosity/100], of less than 1.55, and, a coefficient of thermal expansion (25-800° C.) of no greater than 17×10−7/° C. The ceramic filter further exhibits a median pore diameter, d50, of at least 4 micrometers and up to 40 micrometers. A method of making the filter is provided.

Abstract: This invention is a method of manufacturing oxide porous bodies and components of alumina and magnesia, using alumina and magnesia powders as raw materials, wherein (1) cold isostatic pressure (CIP) of at least 100 MPa is applied to the materials to introduce a plastic deformation with lattice disorder in the surface vicinity without external changes in the particles, (2) by sintering (calcining) the powders with the above described plastic deformation, the microscopic plastic deformation is removed and, at the same time, formation and growth of necks between grains is induced, (3) from the above described steps (1) and (2), a highly porous body with a structure constituted by a three dimensional network of grains connected through the necks is produced.

Abstract: Strong, high-surface-area honeycombs of alumina or other ceramic composition are provided by compounding and shaping a moldable ceramic powder extrusion batches including a cellulosic temporary binder and a high-surface-area boehmite precursor for a permanent binder, hydrating the shaped honeycomb to develop a boehmite binding phase, and calcining the hydrated body to develop the binder and provide a ceramic honeycomb of high strength and porosity.

Abstract: Refractory investment material for forming a positive replication of a tooth structure on which a high-alumina based porcelain tooth restoration is to be formed, the material being formed from a refractory powder which includes alumina mixed with a liquid carrier comprising an aqueous dispersion of silicon dioxide.

Abstract: A dielectric ceramic article precursor and a process for preparing a dielectric ceramic article are presented. The ceramic article precursor comprises a crystalline aluminosilicate zeolite or an amorphous aluminosilicate and a glass phase. The ceramic article precursor can optionally contain at least one forming aid selected from binders, plasticizers and surfactants. Metal oxide additives such as B2O3 or SnO2 as well as metal oxide precursor additives such as nitrates or carbonates of metals such as boron or tin can also be included in the ceramic article precursor. The process for preparing a dielectric ceramic article involves forming a mixture from the above components into a shaped article such as a tape and then calcining the shaped article at a temperature of about 700° C. to about 1000° C. for a time of about 0.5 to about 24 hours.

Abstract: The present invention provides aluminum oxide crystalline materials including dopants and oxygen vacancy defects and methods of making such crystalline materials. The crystalline materials of the present invention have particular utility in optical data storage applications.

Abstract: Ceramic mass and thermal transfer media suitable for use in thermal regenerative oxidizers made using a mixture of a ball clay, talc and optionally a dolomitic limestone have enhanced resistance to environments containing halogens and hydrogen halides. The media preferably comprises less than 0.25% by weight of alkali metal, expressed as the oxide, and has a cordierite: silica phase ratio of less than 1.2:1, as determined by X-ray diffraction.

Abstract: A ceramic sintered body comprising from 90 to 99.8% by volume of cordierite and from 0.2 to 10% by volume of mullite based on 100% by weight of a total sum of the contents of the cordierite and the mullite, and having a density of 2.48 g/cm3 or more.

Abstract: A ceramics structure body having chemical composition of 42 to 56 wt % of SiO2, 30 to 45 wt % of Al2O3 and 12 to 16 wt % of MgO, crystalline phase mainly composed of cordierite, a porosity of 55 to 65%, an average pore size of 15 to 30 &mgr;m; and the total area of pores exposed on surfaces of partition walls constituting the honeycomb ceramics structure body being 35% or more of the total area of partition wall surfaces. Fifteen to 25 wt % of graphite and 5 to 15 wt % of a synthetic resin are added as a pore forming agent to a cordierite-forming raw material; the resultant is kneaded and molded into a honeycomb shape; and the resultant is dried and fired to produce above-mentioned honeycomb ceramics structure body. According to this honeycomb ceramics structure body, a low pressure loss and a high collection efficiency can be attained.

Abstract: A particulate sealant for forming plugs in selected cells of honeycomb structures and consisting essentially, by weight, of about 70 to 90% ceramic blend, the ceramic blend being raw ceramic materials selected to form a composition consisting essentially of in percent by weight about 12 to 16% MgO, about 33 to 38% Al2O3, and about 49 to 54% SiO2, which will form cordierite (2MgO.2Al2O3.5SiO2) on firing, and about 10 to 30% binder system comprising a thermoplastic polymer capable of forming a gel or a thermosetting resin.

Abstract: A ceramic comprising predominately a cordierite-type phase approximating the stoichiometry Mg2Al4Si5O18 and having a coefficient of thermal expansion (25-800° C.) of greater than 4×10?7/° C. and less than 13×10?7/° C. and a permeability and a pore size distribution which satisfy the relation 2.108 (permeability)+18.511 (total pore volume)+0.1863 (percentage of total pore volume comprised of pores between 4 and 40 micrometers)>24.6. The ceramic is suitable in the fabrication of cellular, wall-flow, diesel particulate filters having a pressure drop in kPa that at an artificial carbon soot loading of 5 grams/liter and a flow rate of 26 scfm is less than 8.9-0.035 (number of cells per square inch)+300 (cell wall thickness in inches), a bulk filter density of at least 0.60 g/cm3 and a volumetric heat capacity of at least 0.67 J cm?3 K?1 as measured at 500° C.

Abstract: Low thermal expansion ceramics contains a cordierite crystal phase, wherein a phase of a crystalline compound containing at least one element selected from the group consisting of an alkaline earth element other than Mg, a rare earth element, Ga and In, is precipitated in the grain boundaries of said crystal phase, said ceramics has a relative density of not smaller than 95%, a coefficient of thermal expansion of not larger than 1×10?6/° C. at 10 to 40° C., and a Young's modulus of not smaller than 130 GPa. That is, the ceramics has a small coefficient of thermal expansion, is deformed very little depending upon a change in the temperature, has a very high Young's modulus and is highly rigid and is resistance against external force such as vibration. Accordingly, the ceramics is very useful as a member for supporting a wafer or an optical system is a lithography apparatus that forms high resolution circuit patterns on a silicon wafer.

Abstract: Truss systems and components thereof for use in connection with supporting rock formations in underground mines, caverns, storage vaults, and so forth. Multiple types of truss brackets of unique design are incorporated in the various systems which also include tensioning tie rods and anchor bolts. The truss bracket components are designed so that a minimum or no force couples are exhibited when the tie rods employed are tightened down in their interconnection between associated truss brackets. Various truss systems accommodate mine entries, two-way, three-way, and four-way passageway configurements, and so forth. Additionally, provision is made for intercoupling trusses together.