Abstract: The invention relates to a composite target in the form of a bar made of ceramic powders and designed to be evaporated under an electron beam, the target comprising zirconia and at least one zirconia stabilizer. In characteristic manner, said target is wherein said zirconia stabilizer is at a molar content lying in the range 2% to 30% and wherein said zirconia is formed by more than 90% of a monoclinic phase. The invention is applicable to fabricating a ceramic thermal barrier of low thermal conductivity and high thermomechanical strength formed by evaporation under an electron beam.

Abstract: This invention concerns a non-basic refractory batch as well as its use.

Abstract: A reinforced composite material, having isotropic thermal expansion properties and a low coefficient of thermal expansion over at least the temperature range of from about 0° C. to at least about 150° C., which composite material comprises in combination a first continuous phase comprising a three dimensional preformed bonded powder material reinforcement, including a bonding agent, and in which the bonded powder material is chosen from the group consisting of zirconium tungstate, hafnium tungstate, zirconium hafnium tungstate, and mixtures of zirconium tungstate and hafnium tungstate, and a second continuous phase matrix material chosen from the group consisting of aluminium, aluminium alloys in which aluminium is the major component, magnesium, magnesium alloys in which magnesium is the major component, titanium, titanium alloys in which titanium is the major component, engineering thermoplastics and engineering thermoplastics containing a conventional solid filler.

Abstract: A thermal barrier coating composition is provided. The composition has a base oxide, a primary stabilizer, and at least two additional cationic oxide dopants. Preferably, a pair of group A and group B defect cluster-promoting oxides is used in conjunction with the base and primary stabilizer oxides. The new thermal barrier coating is found to have significantly lower thermal conductivity and better sintering resistance. In preferred embodiments, the base oxide is selected from zirconia and hafnia. The group A and group B cluster-promoting oxide dopants preferably are selected such that the group A dopant has a smaller cationic radius than the primary stabilizer oxide, and so that the primary stabilizer oxide has a small cationic radius than that of the group B dopant.

Abstract: Using as a negative thermal expansion material a double oxide containing at least partly a compound represented by the chemical formula: RQ,O, (wherein R is Zr, Hf or a tetravalent metallic element represented by a mixture system of these, and Q is a hexavalent metallic element selected from W and Mo), and using as a positive thermal expansion material a material containing at least partly a compound represented by the chemical formula: MQX, (wherein M is Mg, Ca, Sr, Ba, Ra or a divalent metallic element represented by a mixture system of any of these, Q is a hexavalent metallic element selected from W and Mo, and X is an element selected from O and S), these are mixed preferably in a weight ratio of 1:1 and are synthesized to obtain a material whose coefficient of thermal expansion is substantially zero over a wide temperature range, i.e., a zero thermal expansion material. Using this zero thermal expansion material, high-precision and high-performance practical component parts can be obtained.

Abstract: Using as a negative thermal expansion material a double oxide containing at least partly a compound represented by the chemical formula: RQ2O8 (wherein R is Zr, Hf or a tetravalent metallic element represented by a mixture system of these, and Q is a hexavalent metallic element selected from W and Mo), and using as a positive thermal expansion material a material containing at least partly a compound represented by the chemical formula: MQX4 (wherein M is Mg, Ca, Sr, Ba, Ra or a divalent metallic element represented by a mixture system of any of these, Q is a hexavalent metallic element selected from W and Mo, and X is an element selected from O and S), these are mixed preferably in a weight ratio of 1:1 and are synthesized to obtain a material whose coefficient of thermal expansion is substantially zero over a wide temperature range, i.e., a zero thermal expansion material. Using this zero thermal expansion material, high-precision and high-performance practical component parts can be obtained.

Abstract: A thermal barrier coating composition comprising a base oxide, a primary stabilizer oxide, and at least one dopant oxide is disclosed. Preferably, a pair of group A and group B defect cluster-promoting oxides is used in conjunction with the base and primary stabilizer oxides. The new thermal barrier coating is found to have significantly lower thermal conductivity and better sintering resistance. The base oxide is selected from the group consisting of zirconia and hafnia and combinations thereof. The primary stabilizing oxide is selected from the group consisting of yttria, dysprosia, erbia and combinations thereof. The dopant or group A and group B cluster-promoting oxide dopants are selected from the group consisting of rare earth metal oxides, transitional metal oxides, alkaline earth metal oxides and combinations thereof. The dopant or dopants preferably have ionic radii different from those of the primary stabilizer and/or the base oxides.

Abstract: Using as a negative thermal expansion material a double oxide containing at least partly a compound represented by the chemical formula: RQ2O8 (wherein R is Zr, Hf or a tetravalent metallic element represented by a mixture system of these, and Q is a hexavalent metallic element selected from W and Mo), and using as a positive thermal expansion material a material containing at least partly a compound represented by the chemical formula: MQX4 (wherein M is Mg, Ca, Sr, Ba, Ra or a divalent metallic element represented by a mixture system of any of these, Q is a hexavalent metallic element selected from W and Mo, and X is an element selected from O and S), these are mixed preferably in a weight ratio of 1:1 and are synthesized to obtain a material whose coefficient of thermal expansion is substantially zero over a wide temperature range, i.e., a zero thermal expansion material. Using this zero thermal expansion material, high-precision and high-performance practical component parts can be obtained.

Abstract: The invention refers to a material which is chemically long-term stable in a neutral or slightly acid environment and which can be used both as bioactive bone replacement material, e.g. in the form of a coating applied onto metallic prosthesis sticks by thermal spraying, and as substrate material in biotechnology, e.g. in the form of a ceramic sheet. According to the invention, said material comprises 15-45% by weight CaO, 40-45% by weight P2O5, 10-40% by weight ZrO2 and fluoride, said material further comprises two crystalline phases being apatite and calcium zirconium phosphate, and a secondary glass phase. Said material has a very high chemical long-term stability, compared to known materials which can also be produced by means of a melting process.

Abstract: Refractory coatings comprising unstabilized zirconia, silica, and, optionally, zircon and/or mullite are disclosed herein. The unstabilized zirconia, silica, and optional zircon and/or mullite are applied as a slurry onto ceramic substrates such as silicon carbide and fired. The refractory coatings of the present invention maintained good edge definition and color when applied to ceramic substrates and subjected to temperatures over 1100° C.

Abstract: The invention provides a stable metal zirconium phosphates having formula (I), in which X is a metal or a combination of metals selected from Co, Mn, Ni, Cu, Cd, Fe, Cr, Al, Sn, V, Zn, Sc, Na, Mg, Ca and Si; and n has a molar value in the range of 1.25 to 22. These metal zirconium phosphates are prepared by sol-gel process.

Abstract: There is provided a ceramic coating of zirconium diboride, silicon carbide, zirconium phosphate and silicon phosphate, that protects carbon-based materials from oxidation in high temperature oxidizing environments. The coating is applied at room temperature with a brush, roller, squeegee, doctor blade, spray gun, etc., and cured at room temperature. The cured material forms a hard, protective ceramic shell. The coating can be applied to various carbon based materials including, but not limited to, amorphous carbon foam, graphitic foam, monolithic graphite, and carbon-carbon composites. Alternative compositions of the coating can be the partial or complete substitution of hafnium diboride for zirconium diboride. Additional modifications of the coating can be accomplished by partial substitution of the borides or silicides of Ti, Ta, Cr, Nb, Ti, V, Re, for zirconium diboride.

Abstract: An improved submerged entry nozzle is provided which is useful in the casting of aluminum killed molten steel. The nozzle has an improved slagline sleeve or collar which surrounds the outer portion of the nozzle to protect it from corrosion during the casting process. The slagline sleeve is made from resin bonded zirconia/graphite which has been formulated so that upon curing of the resin to form resite, there is a reduction in the contractile tendency which results in a reduction in stress fracturing. The reduction of the contractile tendency and the resulting resistance to stress fracturing is achieved by adding an effective amount of calcium oxide to the resin-zirconia-graphite mixture which is used to form the sleeve.

Abstract: A ceramic including a first phase having a general formula R1+(x/2)Zr4P6-xSixO24 where R is selected from the group consisting of Ba, Ca, and Sr and 0≦x≦2, wherein the first phase has a volumetric heat capacity (Cp1), and at least 10 weight percent of a second phase having a volumetric heat capacity (Cp2), wherein Cp2>Cp1. The ceramic has a coefficient of thermal expansion from 22° to 1000° C. of −15×10−7/° C. to +15×10−7/° C., a permeability of at least 0.25×10−12 m2, a total porosity of at least 35% by volume, and a median pore diameter of at least 6 micrometers, and a volumetric heat capacity of the solid Cp(solid) of at least 3.15 J/cm3 K.

Abstract: A homogeneous bulky porous ceramic material is provided, the average pore diameter D50 of which is less than 4 &mgr;m and the closed porosity of which is less than 2 &mgr;m, and having a bubble point that matches the pore diameter measured on the material. A hollow fiber based on the material and a module employing such fibers together with a paste constituting a precursor for the material and including a pore-forming agent are also provided.

Abstract: The present invention provides a method of making a ceramic filter, by forming a mixture from NZP-forming raw material powders selected from metal oxide sources capable of reacting to form a reaction product comprising an NZP-type phase having the general formula R1+(y/2)Zr4P6−ySiyO24 where 0≦y≦1.0 and R is one or more of the metals Ca, Sr, and Ba, pre-reacted powder having the same general formula, and mixtures thereof; and a precursor additive selected from the group consisting of silica precursor, zirconia precursor, and mixtures thereof; shaping the mixture into a green structure; and, firing the green structure to produce a ceramic filter having an open porosity of at least 35% by volume, a median pore size of at least 8 micrometers and a permeability of at least 0.30×10−12 m2, and being suitable as a diesel particulate filter.

Abstract: A dry refractory composition having superior insulating value. The dry refractory composition also may have excellent resistance to molten metals and slags. The composition includes filler lightweight material, which may be selected from perlite, vermiculite, expanded shale, expanded fireclay, expanded alumina silica hollow spheres, bubble alumina, sintered porous alumina, alumina spinel insulating aggregate, calcium alumina insulating aggregate, expanded mulllite, cordierite, and anorthite, and matrix material, which may be selected from calcined alumina, fused alumina, sintered magnesia, fused magnesia, silica fume, fused silica, silicon carbide, boron carbide, titanium diboride, zirconium boride, boron nitride, aluminum nitride, silicon nitride, Sialon, titanium oxide, barium sulfate, zircon, a sillimanite group mineral, pyrophyllite, fireclay, carbon, and calcium fluoride.

Abstract: A body of carbonaceous or other material for use in corrosive environments such as oxidising media or gaseous or liquid corrosive agents at elevated temperatures, in particular in molten salts such as cryolite, is coated with a protective surface coating which improves the resistance of the body to oxidation or corrosion and which may also enhance the bodies electrical conductivity and/or its electrochemical activity. The protective coating is applied in one or more layers from a colloidal slurry containing reactant or non-reactant substances, or a mixture of reactant and non-reactant substances, in particular mixtures containing silicon carbide and molybdenum silicide or silicon carbide and silicon nitride, which when the body is heated to a sufficient elevated temperature reaction sinter as a result of micropyretic reaction and/or sinter without reaction to form the protective coating.

Abstract: The present invention relates to porous calcium zirconate/magnesia composites having a thermally and chemically stable porous structure, which consist of sintered compacts having a fine composite structure stable under high temperatures due to uniformly dispersed equimolar amounts of calcium zirconate [CazrO3] and magnesia [MgO] and controlled grain growth, and a method of producing the same, and the present porous composites are useful as, for instance, a functional material for filtering highly corrosion resistant materials, lightening members used at super-high temperatures, catalyst carriers, insulation or sound-absorbing materials, and the like.

Abstract: A ceramic member is constituted with a zirconia-containing ceramic material containing 20% by volume or more of a zirconia series ceramic phase mainly composed of a zirconium oxide. The zirconia-containing ceramic material satisfies: KC/(dA)≧5 by using an exponential value A set within a range from −0.41 to −0.37 width, d being an average grain size (unit: &mgr;m) and KC being a fracture toughness value (unit: MPa·m½). An edge portion appearing in the form of a ridge is formed at an intersection between two edge forming surfaces 4a and 5 to the outer surface of the member, and the edge portion is formed as a sharp edge portion E having a width w of 0.15 mm or less for the top end of the edge appearing on a cross section taken along an arbitrary plane in perpendicular to the direction of the ridge.

Abstract: An improved submerged entry nozzle is provided which is useful in the casting of aluminum killed molten steel. The nozzle has an improved slagline sleeve or collar which surrounds the outer portion of the nozzle to protect it from corrosion during the casting process. The slagline sleeve is made from resin bonded zirconia/graphite which has been formulated so that upon curing of the resin to form resite, there is a reduction in the contractile tendency which results in a reduction in stress fracturing. The reduction of the contractile tendency and the resulting resistance to stress fracturing is achieved by adding an effective amount of calcium oxide to the resin-zirconia-graphite mixture which is used to form the sleeve.

Abstract: Ceramic monoliths are described which exhibit tunable coefficients of thermal expansion from about −5 to −11×10−6° C.−1 near ambient temperatures. These two-phase ceramics, which are fabricated, for example, by reactive sintering of WO3 and ZrO2, consists of a matrix of ZrW2O8 with inclusions of ZrO2 having diameters less than 10 &mgr;m. Additives may increase the density of the monoliths to greater than 98% of the calculated density. Green body densities, pre-sintered particle size distribution, sintering atmosphere, microstructure, and mechanical properties are discussed. These ceramics may be used as substrates for thermally compensating fiber Bragg gratings.

Abstract: Transition metal NZP type compounds are synthesized. Examples of these compounds include MnZr4(PO4)6, FeZr4(PO4)6, CoZr4(PO4)6, NiZr4(PO4)6, and CuZr4(PO4)6. These compounds are synthesized by the Xerogel process. These transition metal NZP type compounds can be used as colorants in applications such as ceramic glazes where high thermal stability of the colorant is important.

Abstract: Ceramic monoliths are described which exhibit tunable coefficients of thermal expansion from about −5 to −11×10−6° C.−1 near ambient temperatures. These two-phase ceramics, which are fabricated, for example, by reactive sintering of WO3 and ZrO2, consists of a matrix of ZrW2O8 with inclusions of ZrO2 having diameters less than 10 &mgr;m. Additives may increase the density of the monoliths to greater than 98% of the calculated density. Green body densities, pre-sintered particle size distribution, sintering atmosphere, microstructure, and mechanical properties are discussed. These ceramics may be used as substrates for thermally compensating fiber Bragg gratings.

Abstract: Negative thermal expansion materials, methods of preparation and uses therefor are disclosed. The materials are useful for negative thermal expansion substrates, such as those used for optical fiber gratings.

Abstract: A silver-colored sintered product having excellent corrosion resistance containing titanium, carbon and boron as indispensable constituent elements, and including in the sintered product composition a titanium boride phase or a boride phase which contains titanium as a chief metal element and a titanium carbide phase or a carbide phase which contains titanium as a chief metal element and a method of producing the same. The sintered product has a flexural strength of not smaller than 700 MPa, a Vickers' hardness of not smaller than 9.0 GPa and a fracture toughness of not smaller than 5.0 MPa·m½.

Abstract: An insulation material which is substantially free of fibers and which has a density of less than about 2.5 g/cc and a thermal conductivity of less than about 5 W/Km is formed from a composition comprising at least about 2%, by weight, carbon. The insulation material is resistant to thermal shock and is easily machined.

Abstract: The present invention provides a ceramic sintered body excellent in oxidation resistance under high temperatures and markedly superior to the conventional ceramic sintered body in the mechanical strength over a wide temperature range of between room temperature and 1,500.degree. C. The ceramic sintered body of the present invention comprises at least one ceramic crystal grain selected from the group consisting essentially of a monosilicate represented by the general formula RE.sub.2 SiO.sub.5, where RE denotes a IIIa group element including yttrium, and a disilicate represented by the general formula RE.sub.2 Si.sub.2 O.sub.7, where RE denotes a IIIa group element including yttrium, and at least one additional element selected from the group consisting of Al, Cr, Hf, Nb, Zr, Ti, V, Ta, Ca and Mg which is segregated in the boundaries of the ceramic crystal grains in an amount of 0.1 to 15% by weight of the sintered body in terms of the oxide thereof.

Abstract: Disclosed is a composition of an essentially solid phase state having as components, a liquid hydrophilic organic polymer, an aqueous salt solution containing at least one metallic or metalloid element, and a coagulating agent. The composition on calcination provides a metal-containing powder having an average particle size of 1 micrometer or less. Such metal-containing powders are of value in the preparation of industrial catalysts, ceramics, electronic components, or as fillers in plastics, paints or cosmetics.

Abstract: A pigmentary material comprises silver in a lattice of crystalline zirconia, which material contains at least 0.4% by weight of the silver. A process for preparing a pigmentary material comprising silver in a lattice of crystalline zirconia comprises calcining a zirconium component which yields the zirconia, and a silver component which yields the silver, forming a calcination mixture of the resultant zirconium and silver moieties and cooling the mixture, the weight of fluoride compound in the total weight of the components to be calcined being less than 6%.

Abstract: An improved thermal barrier coating for metal substrates such as superalloys is provided. The coating is a slurry composition, comprising spheres of zirconia, at least some of which are hollow, contained within a porous oxide matrix, such as aluminosilicate. The slurry composition can be applied by slurry casting or similar techniques to the desired surface. Coating methods involve the application of successive layers of variations of the slurry composition, with various curing techniques used between layers and after the final coating is applied. Another embodiment of this invention embraces a composite coating, comprising (i) an oxide matrix phase; (ii) zirconia spheres embedded in the oxide matrix; and (iii) a porous phase.

Abstract: Hydrophilizing compositions based on aqueous colloidal silica and zirconyl salts and a process for rendering surfaces hydrophilic with such compositions are provided.

Abstract: Gels based on a network of oxygen-bridged metal and/or semi-metal atoms and produced using a hydrolytic sol-gel process are often not homogeneous. Known non-hydrolytic sol-gel processes give rise to gels containing halogen.A novel non-hydrolytic sol-gel process has been found which gives rise to halogen-free and homogeneous gels and to xerogels obtainable therefrom.In this process, one or more compounds (I) from the series of metal or semi-metal alkoxides, oxoalkoxides, amides or oxoamides are condensed, with elimination of carboxylic acid esters or carboxylic acid amides, until gelation occurs with one or more compounds (II) from the series of metal or semi-metal carboxylates or oxocarboxylates in an anhydrous organic solvent containing no hydroxyl groups.Preferred gels and xerogels contain in the network metal or semi-metal atoms from main group and subgroup III to V and from the rare-earth elements.

Abstract: Non-magnetic ceramics for recording/reproducing heads comprising an alumina and any one of a compound selected from silicon carbide, boron carbide, zirconium carbide, titanium oxide, aluminum boride or zirconium boride, said ceramics having a Young's modulus of not smaller than 370 Gpa and a surface coarseness Ra after milling of not larger than 100 nm, and a method of producing the same.

Abstract: An antibacterial ceramic contains an antibacterial material produced by loading an antibacterial metal such as silver on a calcium ceramic carrier and an inorganic material such as cordierite, and has a bulk density of 0.6-1.2 g/cm.sup.3. An antibacterial ceramic filter contains an antibacterial material produced by loading an antibacterial metal such as silver on a calcium ceramic carrier, an aggregate such as mullite, and a binder such as frit, and has a porosity of 20% or more. The light-weight antibacterial ceramic is suitably applicable to a roof garden or the like. The antibacterial ceramic filter can remove and extirpate various bacteria and suspensions.

Abstract: The present invention provides a method for preparing a ceramic mixed-oxide of at least two metals including mixing an alloy with a ceramic oxide. The alloy including a metal selected from the group consisting of aluminum, calcium, lithium, magnesium, silicon, titanium, yttrium, and zirconium. The alloy also includes an element that is to be present in the ceramic mixed-oxide. The element is different from the metal and is selected from the group consisting of aluminum, calcium, lithium, magnesium, a combination of magnesium and silicon, silicon, titanium, yttrium, and zirconium. The ceramic oxide includes a metal that is to be present in the ceramic mixed oxide. The alloy and ceramic oxide are co-milled. The mixed and co-milled alloy and ceramic oxide are reaction-sintered, thereby oxidizing the metal and element of the alloy to produce the ceramic mixed-oxide.

Abstract: A process for making inorganic gels by reaction of tetraalkoxy orthosilicates, tetraalkoxy titanates and tetraalkoxy zirconates with strong carboxylic acids. Water need not be present initially as a reactant. Optically clear, very small pore size, narrow pore size distribution, and high specific area inorganic gels useful for abrasion-resistant coatings, optical applications, catalyst or enzyme support, gas separation, or chromatography packing are thus produced.

Abstract: Three families of ceramic compositions having the given formula: .phi..sub.1+X Zr.sub.4 P.sub.6-2X Si.sub.2X O.sub.24, .phi..sub.1+X Zr.sub.4-2X Y.sub.2X P.sub.6 O.sub.24 and .phi..sub.1+X Zr.sub.4-X Y.sub.X P.sub.6-2X Si.sub.X O.sub.24 wherein .phi. is either Strontium or Barium and X has a value from about 0.2 to about 0.8 have been disclosed. Ceramics formed from these compositions exhibit very low, generally near neutral, thermal expansion over a wide range of elevated temperatures.

Abstract: An oxide type solid lubricant is formed of a powder of a fired composite ceramic material resulting from heating a mixture of BaZrO.sub.3 and Cr.sub.2 O.sub.3 powders in which the Cr.sub.2 O.sub.3 content is up to 80% by weight.

Abstract: A novel composition comprises aluminum borate and zirconium borate. Preferably, the composition is prepared by coprecipitation. The composition is useful as a sorbent or as a catalyst material.

Abstract: A process is described for producing ceramic fibres composed of titanium boride, zirconium boride or hafnium boride. The boride fibres are obtained by reacting a boron oxide precursor fibre with a titanium halide, zirconium halide or hafnium halide gas in the presence of hydrogen. Ceramic titanium, zirconium or hafnium nitride fibres may also be produced by the process, by means of the additional presence of nitrogen gas in the gas phase. The process is conducted at temperature higher than 500.degree. C.

Abstract: This invention relates generally to a novel directed metal oxidation process which is utilized to produce self-supporting bodies. In some of the more specific aspects of the invention, a parent metal (e.g., a parent metal vapor) is induced to react with at least one solid oxidant-containing material to result in the directed growth of a reaction product which is formed from a reaction between the parent metal and the solid oxidant-containing material. The inventive process can be utilized to form bodies having substantially homogeneous compositions, graded compositions, and macrocomposite bodies.

Abstract: Compounds that satisfy the general formula A.sub.1-Y.sup.4+ A.sub.Y.sup.1+ A.sub.Y.sup.3+ V.sub.2-X E.sub.X O.sub.7 exhibit isotropic NTE behavior above a temperature of about 100.degree. C. Y is from about 0.0 to about 0.4, and more preferably is about 0.2. X is from about 0.6 to about 1.4, and is more preferably about 1. Particularly suitable NTE compounds have X about 1 and Y about 0. A.sup.4+ is selected from the group consisting of Hf, Zr, Zr.sub.a M.sub.b, Hf.sub.a M.sub.b and mixtures thereof wherein a plus b equals one and M is selected from the group consisting of Ti, Ce, Th, U, Mo, W, Pb, Sn, Ge and Si. More preferably, A.sup.4+ is selected from the group consisting of Hf and Zr. A.sup.1+ is selected from the group consisting of the alkali earth metals, A.sup.3+ is selected from the group consisting of the rare earth metals, and E is selected from the group consisting of P and As. The NTE materials may be incorporated into compositions such as epoxy and ceramic compositions.

Abstract: This invention is directed to a method for preparing materials comprising metal nitrides by the photolytic/pyrolytic decomposition of metal amides. The metal amides may be zirconium and/or niobium amides, which may additionally contain titanium amides.

Abstract: This invention relates generally to a novel method of manufacturing a composite body. More particularly, the present invention relates to a method for modifying the resultant properties of a composite body, by, for example, minimizing the amount of porosity present in the composite body. Moreover, additives, whether used alone or in combination, (1) can be admixed with the permeable mass, (2) can be mixed or alloyed with the parent metal, (3) can be placed at an interface between the parent metal and the preform or mass of filler material, (4) or any combination of the aforementioned methods, to modify properties of the resultant composite body. Particularly, additives such as VC, NbC, WC, W.sub.2 B.sub.5, TaC, ZrC, ZrB.sub.2, SiB.sub.6, SiC, MgO, Al.sub.2 O.sub.3, ZrO.sub.2, CeO.sub.2, Y.sub.2 O.sub.3, La.sub.2 O.sub.3, MgAl.sub.2 O.sub.4, HfO.sub.2, ZrSiO.sub.4, Yb.sub.2 O.sub.3 and Mo.sub.2 B.sub.

Abstract: Compounds that satisfy the general formula A.sub.1-Y.sup.4+ A.sub.Y.sup.1+ A.sub.Y.sup.3+ V.sub.2-X P.sub.X O.sub.7 exhibit isotropic NTE behavior in the range of normal ambient temperatures. Y is from about 0.0 to about 0.4, and more preferably is about 0.2. X is from about 0.6 to about 1.4, and is more preferably about 1. Particularly suitable NTE compounds have X about 1 and Y about 0. A.sup.4+ is selected from the group consisting of Hf, Zr, Zr.sub.a M.sub.b, Hf.sub.a M.sub.b and mixtures thereof wherein a plus b equals one and M is selected from the group consisting of Ti, Ce, Th, U, Mo, Pt, Pb, Sn, Ge and Si. More preferably, A.sup.4+ is selected from the group consisting of Hf and Zr. A.sup.1+ is selected from the group consisting of the alkali earth metals, and A.sup.3+ is selected from the group consisting of the rare earth metals. Such NTE materials exhibit isotropic negative linear expansion at a temperature below about 100.degree. C.

Abstract: Novel self-supporting ceramic structures are produced by the oxidation reaction of a molten metal precursor with a vapor-phase oxidant to form an oxidation reaction product. The resulting ceramic material of the polycrystalline oxidation reaction product consists essentially of an oxidation reaction product and, optionally, one or more non-oxidized constituents of the metal precursor.

Abstract: There is disclosed a method for making a self-supporting ceramic composite article having a porous core bearing a dense surface layer formed integrally with said core. A preform comprises a filler material and parent metal distributed therethrough, wherein the volume percent of parent metal is sufficient to form a volume of oxidation reaction product exceeding the total volume available within said preform. The parent metal is melted and reacted with an oxidant to form an oxidation reaction product filling the spatial volume and leaving voids. The reaction is continued to further transport molten parent metal through the oxidation reaction product to at least one surface of the preform to form oxidation reaction product on said surface substantially free of voids thereby forming a relatively dense surface layer.

Abstract: A method of growing mixed crystals having at least two lattice sites each having a different number of adjacent oxygen ions from melts of oxidic multi-component systems, homogeneous mixed crystals being grown such that the cations intended to occupy the first lattice site having the highest number of adjacent oxygen ions and to occupy the second lattice site having the next lowest number of adjacent oxygen ions are chosen such that the ratio of the bond length of the cations in the first lattice site to the bond length of the cations in the second lattice site is in the range from 0.7 to 1.5.

Abstract: Improved silicone-free, continuous zirconia fibers have diameters greater than 5 micrometers and high tensile strengths. In another aspect, strong, flexible, zirconia fibers are prepared in a process involving the addition of colloidal ZrO.sub.2 particles to a fiber precursor solution.