Abstract: A method for producing an oil-binding agent of granular open-porous structure with a silicate ceramic matrix by using recovered paper material and clay. The method is characterized in that, in each case based on the entire raw material, 35 to 60 wt.-% sewage sludge with a water content of between 70 and 85 wt.-%, 25 to 55 wt.-% recovered paper material with a water content of between 35 and 55 wt.-%, 10 to 25 wt.-% clay and optionally 1 to 3 wt.-% zeolite, 1 to 2 wt.-% quicklime and/or up to 3 wt. % fly ash are mixed to a homogeneous mixture. The raw material thus obtained is subsequently processed in order to form particles having an average diameter of 4 to 6 mm. The particles are then dried and subsequently burnt at 950 to 1050° C. The oil-binding agents produced according to said method have a bulk density of between 0.4 and 0.75 kg/1 and a oil-binding capability of 0.7 to 1.0 1 oil per oil-binder.

Abstract: In a method for producing silicon-containing ceramic structures, structures of a ceramic precursor polymer are provided on the surface of a substrate, the ceramic precursor polymer being selected from the group including polysiloxanes, polycarbosilanes, polysilazanes and/or polyureasilazanes, and the ceramic precursor structures being ceramicized on the substrate. In the method, the structures of the ceramic precursor polymer have a height of ?20 ?m and a width perpendicular to their longitudinal axis of ?500 ?m.

Abstract: [Object] Providing a solidified ceramic body with an improved mechanical strength, wherein the solidified ceramic body is fabricated by activating ceramic powder through mechanochemical treatment and solidifying the activated ceramic powder through alkali treatment. [Method of Solution] Activated ceramic powder having mechanochemically amorphized surfaces is obtained by grinding ceramic powder which is composed of silicic acid and/or silicate at least at surfaces thereof (grinding process). Inorganic fibers and/or plastic fibers are added to the activated ceramic powder and are mixed with the activated ceramic powder (mixing process), and a solidified ceramic body is obtained by adding alkali water solution containing alkaline metal hydroxide and/or alkaline earth metal hydroxide to the powder (alkali treatment process).

Abstract: This invention relates to a method for manufacturing silicon-containing particles characterized by preparing a uniform phase comprising a curable composition that includes a silicon-containing compound having in one molecule one or more reactive functional groups per 50 silicon atoms and an oil that does not participate in curing of the composition, then curing the composition, and causing phase separation from the oil for obtaining the silicon-containing particles; and to silicon-containing particles obtained by the above method. The method provides silicon-containing particles of an extremely small diameter in a simple process without the use of surfactants. And the silicon-containing particles possess excellent dispersibility in oil and a high degree of ceramification by baking.

Abstract: A honeycomb structured body of the present invention is a honeycomb structured body in which plural pillar-shaped honeycomb units are bonded to one another through sealing material layers, each unit having in the longitudinal direction a large number of cells placed in parallel with a cell wall interposed therebetween. Herein, each honeycomb unit includes inorganic fibers and/or whiskers in addition to inorganic particles. A cross-sectional area of the honeycomb unit on a cross section perpendicular to the longitudinal direction is at least about 5 cm2 and at most about 50 cm2. A region in which a sealing material layer is not formed is provided on both ends of the side faces of each of the honeycomb unit, each of the ends accounting for at least about 0.3% and at most about 5% of the length of the honeycomb structured body.

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: A method and apparatus for manufacturing ceramic microspheres from industrial slag. The microspheres have a particle size of about 38 microns to about 150 microns. The microspheres are used to create a cement slurry having a density of at least about 11 lbs/g. The resultant cement slurry may then be used to treat subterranean wells.

Abstract: A process for the synthesis of a bioceramic composition comprising calcium phosphosilicate (CPS, Ca10(PO4)4(SiO4)2), the process comprising: providing calcium or a calcium-containing compound, a phosphorus-containing compound and a silicon-containing compound; and forming a precipitate by reacting the compounds in an aqueous phase at an alkali pH.

Abstract: The invention provides a method for producing ceramic nanoparticles, which comprises hydrolyzing a ceramic material in a thin film fluid formed between processing surfaces arranged to be opposite to each other so as to be able to approach to and separate from each other, at least one of which rotates relative to the other.

Abstract: A ceramic powder composition and an optoelectronic device substrate utilizing the ceramic powder composition are disclosed. The optoelectronic device substrate is formed by sintering a ceramic powder composition including 4 to 97 wt % (weight percent) of zircon, 0 to 60 wt % of silicon dioxide, and 0 to 80 wt % of alumina, wherein the sintered ceramic substrate includes first and second crystalline phases, the first crystalline phase is zircon, and the second crystalline phase is at least one of or a combination of alumina, silicon dioxide, and zirconia crystalline phases, furthermore, the second crystalline phase can also includes a mullite crystalline phase.

Abstract: A composite material having utility for removing sulfur from a feedstock comprises a ceramic matrix having a relatively low melting point metal such as tin, zinc, lead or bismuth nanodispersed therein. The material may be prepared from a mixture of particles of a precursor of the ceramic matrix and precursor of the metal. The precursors are selected such that the melting point of the precursor of the ceramic is less than the melting point of the precursor of the metal. The mixture of precursor materials is heated to a temperature sufficient to melt the precursor of the ceramic material so as to coat it onto the precursor of the metal. The ceramic precursor is then reacted so as to convert it to a ceramic. Thereafter, the precursor of the metal is converted to a free metal which is retained within the ceramic matrix so as to prevent agglomeration.

Abstract: Metal ion conducting ceramic materials are disclosed having characteristics of high ion conductivity for certain alkali and monovalent metal ions at low temperatures, high selectivity for the metal ions, good current efficiency and stability in water and corrosive media under static and electrochemical conditions. The metal ion conducting ceramic materials are fabricated to be deficient in the metal ion. One general formulation of the metal ion conducting ceramic materials is Me1+x+y?zMIIIyMIV2?ySixP3?xO12?z/2, wherein Me is Na+, Li+, K+, Rb+, Cs+, Ag+, or mixtures thereof, 2.0?x?2.4, 0.0?y?1.0, and 0.05?z?0.9, where MIII is Al3+, Ga3+, Cr3+, Sc3+, Fe3+, In3+, Yb3+, Y3+, or mixtures thereof and MIV is Ti4+, Zr4+, Hf4+, or mixtures thereof.

Abstract: A ceramic composite thin film or layer includes individual graphene oxide and/or electrically conductive graphene sheets dispersed in a ceramic (e.g. silica) matrix. The thin film or layer can be electrically conductive film or layer depending the amount of graphene sheets present. The composite films or layers are transparent, chemically inert and compatible with both glass and hydrophilic SiOx/silicon substrates. The composite film or layer can be produced by making a suspension of graphene oxide sheet fragments, introducing a silica-precursor or silica to the suspension to form a sol, depositing the sol on a substrate as thin film or layer, at least partially reducing the graphene oxide sheets to conductive graphene sheets, and thermally consolidating the thin film or layer to form a silica matrix in which the graphene oxide and/or graphene sheets are dispersed.

Abstract: The present invention relates to a biocompatible ceramic material comprising Baghdadite (Ca3ZrSi2O9), and a method for its preparation. Preferably the Baghdadite is synthetically prepared. The present invention also relates to an implantable medical device comprising biocompatible Baghdadite, and a method for its production. The present invention further relates to a method for improving the long term stability of an implantable medical device and an implantable drug delivery device comprising Baghdadite. Further, the present invention relates to the use of comprising biocompatible Baghdadite in the regeneration or resurfacing of tissue.

Abstract: A synthetic glass family in the quaternary phase field of CaO—SiO2-Al2O3-MgO (CSAM) with hydraulic and pozzolanic properties for use in differing applications in the gas and oil well cementing area. A method of making a mud-to-cement (MTC) slurry and a method for treating oil and gas wells with the MTC slurry containing a homogenous amorphous synthetic glass made from a mixture of inorganic materials selected from the group consisting of CSAM, wherein the cementing glasses with the mixture of inorganic materials are in a 100% amorphous phase with a degree of crystallization of zero.

Abstract: A method for preparing a high-temperature heat-resistant composite material by combining a mixture of submicron alumina powder and submicron silica powder, wherein the ratio of alumina to silica is from about 4:1 to about 5:1, submicron Group II metal oxide powder, and a Group I metal silicate solution to form a slurry, wherein the weight of the Group II metal oxide powder is an amount corresponding to about 5% to about 10% of the weight of the silicate solution; contacting reinforcing high-temperature resistant fibers with the slurry to form a composite precursor composition; and curing the composition at a temperature sufficient to produce the high-temperature heat-resistant composite material capable of resisting temperatures up to about 1400° C. Composite materials prepared according to the method and articles incorporating the material are also presented.

Abstract: A pulling roll for glass manufacture comprised of a high-temperature millboard material. The millboard comprises aluminosilicate refractory fiber, silicate, mica, and kaolin clay. A method of manufacturing a pulling roll is disclosed, together with a roll produced by the methods disclosed herein. The method comprises forming a pulling roll and densifying at least a portion of the pulling roll by exposing to the pulling roll to high temperatures.

Abstract: There is described a Ceramic Powder, a Ceramic Layer and a Layer System of Two Pyrochlore Phases and Oxides. Besides a good thermal insulation property, thermal insulation layer systems must also have a long lifetime of the thermal insulation layer. The layer system has a ceramic layer, which comprises a mixture of two pyrochlore phases.

Abstract: The invention relates to synthetic hybrid rock compositions, articles of manufacture and related processes employing mineral waste starting materials such as mine tailings, mine development rock, ash, slag, quarry fines, and slimes, to produce valuable articles of manufacture and products, which are characterized by superior physical and structural characteristics, including low porosity, low absorption, increased strength and durability, and retained plasticity. The resulting materials are compositionally and chemically distinct from conventional synthetic rock materials as demonstrated by scanning electron microprobe analysis, and are useful in a wide variety of applications, particularly with respect to commercial and residential construction.

Abstract: The invention provides a method for producing a porous body comprising: a starting material mixing step of mixing ceramic particles serving as an aggregate and a sintering aid which includes at least one element selected from the group consisting of rare earth elements, alkaline earth elements, Al and Si such that the amount of the sintering aid is about 1.0% by weight or less relative to the total amount of the ceramic particles and the sintering aid to form a puddle; and a molding and firing step of molding the puddle into a molded body and firing the molded body.

Abstract: Lithium silicate materials are described which can be easily processed by machining to dental products without undue wear of the tools and which subsequently can be converted into lithium silicate products showing high strength.

Abstract: Disclosed is a ceramic substrate including silicon in which the concentration of a silicon oxide and a silicon composite oxide in the surface thereof is less than or equal to 2.7 Atom %.

Abstract: The present invention provides a dielectric film having a high permittivity and a high heat resistance. An embodiment of the present invention is a dielectric film (103) including a composite oxynitride containing an element A made of Hf, an element B made of Al or Si, and N and O, wherein mole fractions of the element A, the element B, and N expressed as B/(A+B+N) range from 0.015 to 0.095 and N/(A+B+N) equals or exceeds 0.045, and has a crystalline structure.

Abstract: The present patent application relates to a reactive ceramic binder in liquid form which is suitable for producing ceramic products from ceramic powder, characterized in that the reactive, liquid ceramic binder comprises liquid organomodified siloxane compounds having organoalkoxysiloxane units of the general formula (I) where the radicals R1 are, independently of one another, identical or different alkyl, alkaryl or aryl radicals which may be interrupted by ether functions, the radicals R2 are, independently of one another, identical or different radicals selected from the group consisting of H and/or alkyl radicals having from 1 to 6 carbon atoms, the radicals R3 are, independently of one another, identical or different divalent, saturated or unsaturated hydrocarbon radicals which have from 1 to 30 carbon atoms and may be interrupted by ether functions and a is greater than or equal to 0 and less than or equal to 2.

Abstract: Disclosed are yellowing-stable, silver-white effect pigments having high whiteness based on synthetic mica flakes and to the use thereof in paints, lacquers, printing inks, plastics, button pastes, ceramic materials, glasses, for coloring seed, as dopant in laser markings of plastics and papers, as additive for laser welding of plastics, as additive for coloring in the foods and pharmaceuticals sectors and in cosmetic formulations, and for the preparation of pigment compositions and dry preparations.

Abstract: A filler for a dental resin composition is disclosed, comprising silica particles derived from a nanoparticulate silica sol, the filler material having at least one crystalline phase. The filler material provides improved wear resistance and other properties.

Abstract: Al2O3-rare earth oxide-ZrO2/HfO2 ceramics (including glasses, crystalline ceramics, and glass-ceramics) and methods of making the same. Ceramics according to the present invention can be made, formed as, or converted into glass beads, articles (e.g., plates), fibers, particles, and thin coatings. The particles and fibers are useful, for example, as thermal insulation, filler, or reinforcing material in composites (e.g., ceramic, metal, or polymeric matrix composites). The thin coatings can be useful, for example, as protective coatings in applications involving wear, as well as for thermal management. Certain ceramic particles according to the present invention can be are particularly useful as abrasive particles.

Abstract: A ceramic honeycomb structure comprising a ceramic honeycomb body comprising axial grooves on its periphery and cell walls constituting a larger number of flow paths inside the grooves, and a peripheral wall layer covering the grooves, wherein there are stress release portions at least partially in the peripheral wall layer and/or between the peripheral wall layer and the grooves. The thermal expansion coefficient of the peripheral wall layer is preferably smaller than those of the cell walls in a radial direction. The peripheral wall layer is preferably formed on the ceramic honeycomb body formed by removing a peripheral wall from a ceramic green body, before or after firing the ceramic honeycomb body.

Abstract: Highly wear-resistant, low-friction ceramic composites suited for machining-tool, sliding-component, and mold-die materials are made available. The ceramic composites characterized are constituted from a phase having carbon of 3 ?m or less, preferably 30 nm or less, average crystal-grain size as the principal component, and a ceramic phase (with the proviso that carbon is excluded). The ceramic phase is at least one selected from the group made up of nitrides, carbides, oxides, composite nitrides, composite carbides, composite oxides, carbonitrides, oxynitrides, oxycarbonitrides, and oxycarbides of Al, Si, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W. The ceramic composites are produced by sintering the source-material powders at a sintering temperature of 800 to 1500° C. and a sintering pressure of 200 MPa or greater.

Abstract: The compound is a clay aqueous suspension made of at least one 2:1 layer phyllosilicate clay mineral, at least one 1:1 layer phyllosilicate clay mineral, and water that can be used to sequester asbestos, such as chrysotile, as well as dust and other fibrous particles, at all scales of contamination.

Abstract: Methods for crosslinking polysiloxane compounds, crosslinked polysiloxane compounds, methods for making ceramic products from the crosslinked polysiloxane compounds, and ceramic products made from the crosslinked polysiloxane compounds.

Abstract: A batch mixture including ceramic-forming ingredients, a pore former, a binder comprising an ammonium salt of an alkylated cellulose binder, and a liquid vehicle, as defined herein. Also disclosed is a method for producing a ceramic precursor article as defined herein having excellent extrusion properties.

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: Disclosed are high-porosity cordierite honeycomb substrates having fine pore size, narrow pore size distribution, little or no microcracking, and a high thermal shock resistance. The porous ceramic honeycomb substrates generally include a primary cordierite ceramic phase as defined herein. Also disclosed are methods for making and using the cordierite substrates.

Abstract: A method of forming a dielectric film that includes nitrogen. The method includes incorporating nitrogen into a dielectric film using a nitridation gas and a rapid thermal annealing process, wherein an ultra-low pressure of equal to or less than about 10 Torr is used for the rapid thermal annealing process.

Abstract: Tunable variable emissivity materials, methods for fabricating tunable variable emissivity materials, and methods for controlling the temperature of a spacecraft using tunable variable emissivity materials have been provided. In an exemplary embodiment, a variable emissivity material has the formula M1(1?(x+y))M2xM3yMnO3, wherein M1 comprises lanthanum, praseodymium, scandium, yttrium, neodymium or samarium, M2 comprises an alkali earth metal, M3 comprises an alkali earth metal that is not M2, and x, y, and (x+y) are less than 1. The material has a critical temperature (Tc) in the range of about 270 to about 320K and a transition width is less than about 30K.

Abstract: The invention is concerned with a material which shows low absorption for UV radiation having a wavelength below 250 nm, low birefringence, high chemical resistance and high radiation resistance and which is therefore particularly usable for making optical components for microlithography. According to the invention the material consists of synthetically produced quartz crystallites which form a polycrystalline structure and have a mean grain size in the range between 500 nm and 30 ?m. The method according to the invention for making a blank from the material comprises providing granules consisting of synthetically produced quartz crystals having a mean grain size in the range between 500 nm and 30 ?m, and sintering the granules to obtain a blank of polycrystalline quartz.

Abstract: An La2O3 powder and an SiO2 powder are mixed with each other, and then heated. By heating, a porous material of LaXSi6O1.5X+12 (8?X?10) as a composite oxide is produced. Subsequently, the porous material is pulverized to obtain a powder, and the powder is added to a solvent to prepare a slurry. The slurry is solidified in a magnetic field to prepare a compact. After that, the compact is sintered, and an oxide ion conductor is obtained thereby.

Abstract: Disclosed herein is a material for altering electromagnetic radiation incident on the material. The material disclosed herein comprises carbon nanotubes having a length (L) that meets the following formula (1): L?½ ???(1) where ? is the wavelength of the electromagnetic radiation incident on the material. Also disclosed herein are methods of altering electromagnetic radiation, including mitigating, intensifying, or absorbing and re-transmitting electromagnetic radiation using the disclosed material.

Abstract: Method of making particle compositions exhibiting improved floodability and/or flowability properties. The compositions generally contain particles and non-surface modified nanoparticles.

Abstract: The present invention relates to use of an aluminosilicate particle for deodorization, wherein the aluminosilicate particle has the composition of: s M(1)xOy t M(2)2O.Al2O3 u SiO2 v RmQn w H2O, wherein M(1) is one or more members selected from the group consisting of Ag, Cu, Zn and Fe, M(2) is one or more members selected from the group consisting of Na, K and H, R is one or more members selected from the group consisting of Na, K, Ca and Mg, Q is one or more members selected from the group consisting of CO3, SO4, NO3, and Cl, s satisfies 0<s?3, and t satisfies 0?t?3, with proviso that s+t is from 0.5 to 3, and u satisfies 0.5?u?6, v satisfies 0<v?2, w satisfies w?0, x satisfies 1?x?2, y satisfies 1?y?3, m satisfies 1?m?2, and n satisfies 1?n?3, and wherein the aluminosilicate particle has a specific surface area of 1 m2/g or more and less than 70 m2/g.

Abstract: A ceramic article comprises ceramic fibers having an aspect ratio of greater than 3:1 and ceramic particles. The ceramic fibers are substantially randomly oriented in three dimensions in the ceramic article. A method of forming the ceramic article includes the step of providing a composition including ceramic fibers having an aspect ratio of greater than 3:1 and ceramic particles. The composition is extruded through a multi-screw extruder having at least three intermeshing screws to form an extrudate. The extrudate is heated to form the ceramic article.

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: Silica-based materials and films having a dielectric constant of 3.7 or below and compositions and methods for making and using same are disclosed herein. In one aspect, there is provided a composition for preparing a silica-based material comprising an at least one silica source, a solvent, an at least one porogen, optionally a catalyst, and optionally a flow additive wherein the solvent boils at a temperature ranging from 90° C. to 170° C. and is selected from the group of compounds represented by the following formulas: HO—CHR8—CHR9—CH2—CHR10R11 where R8, R9, R10 and R11 can independently be an alkyl group ranging from 1 to 4 carbon atoms or a hydrogen atom; and R12—CO—R13 where R12 is a hydrocarbon group having from 3 to 6 carbon atoms; R13 is a hydrocarbon group having from 1 to 3 carbon atoms; and mixtures thereof.

Abstract: Structures and methods for the fabrication of ceramic nanostructures. Structures include metal particles, preferably comprising copper, disposed on a ceramic substrate. The structures are heated, preferably in the presence of microwaves, to a temperature that softens the metal particles and preferably forms a pool of molten ceramic under the softened metal particle. A nano-generator is created wherein ceramic material diffuses through the molten particle and forms ceramic nanostructures on a polar site of the metal particle. The nanostructures may comprise silica, alumina, titania, or compounds or mixtures thereof.

Abstract: By using a halogen-free siloxane and an organometallic compound containing at least one metal other than silicon as feed stocks, and simultaneously atomizing and burning them in a flame, spherical particles of silica-containing compound oxide are prepared which are substantially halogen-free, consist of 0.5-99% by weight of metal oxides and the balance of silica, and have a particle size of 10 nm to 3 ?m. The particles are useful as a filler in epoxy resin base semiconductor sealants, a refractive index modifier or the like.

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: A ceramic honeycomb structure comprised of at least two separate smaller ceramic honeycombs that have been adhered together by a cement comprised of inorganic fibers and a binding phase wherein the smaller honeycombs and fibers are bonded together by the binding phase which is comprised of an amorphous silicate, aluminate or alumino-silicate glass and the cement has at most about 5% by volume of other inorganic particles. The cement may be made in the absence of other inorganic and organic additives while achieving a shear thinning cement, for example, by mixing oppositely charged inorganic binders in water together so as to make a useful cement for applying to the smaller honeycombs to be cemented.

Abstract: Disclosed herein are aluminide coatings. In one embodiment coatings are used as a barrier coating to protect a metal substrate, such as a steel or a superalloy, from various chemical environments, including oxidizing, reducing and/or sulfidizing conditions. In addition, the disclosed coatings can be used, for example, to prevent the substantial diffusion of various elements, such as chromium, at elevated service temperatures. Related methods for preparing protective coatings on metal substrates are also described.

Abstract: A honeycomb filter, for removing from exhaust gas fine solid particles containing carbon, is an aluminum magnesium titanate sintered product obtained by firing at from 1000 to 1700° C. a product formed from a mixture comprising a Mg-containing compound, an Al-containing compound and a Ti-containing compound in the same metal component ratio as the metal component ratio of Mg, Al and Ti in aluminum magnesium titanate represented by the empirical formula MgxAl2(1?x)Ti(1+x)O5 (wherein 0<x<1), or a mixture comprising 100 parts by mass, as calculated as oxides, of the above-mentioned mixture and from 1 to 10 parts by mass of an alkali feldspar represented by the empirical formula (NayK1?y)AlSi3O8 (wherein 0?y?1).