Abstract: Disclosed are an oxide superconductor, and an optimum process for producing the same. The oxide superconductor comprises a base material phase including an oxide superconducting material, the oxide superconducting material including barium (Ba) at least and being free from grain boundaries, and precipitation phases contained in an amount of 1 to 50% by volume in the base material phase and dotted therein in a manner like islands, the precipitation phases being oxides of a metal selected from the group consisting of silicon (Si), aluminum (Al), zirconium (Zr), magnesium (Mg), titanium (Ti), strontium (Sr), tungsten (W), cobalt (Co) and vanadium (V), and being products of decomposition reaction of the base material phase. In the production process, the constituent materials are treated thermally at a partially melting temperature in order to give the above-described novel structure to the oxide superconductor.

Abstract: A moulding compound is described which contains an inorganic powder together with a binder system. The binder system contains a thermoplast having a melting temperature greater than 180.degree. C. A process is also described for making a sintered molding from the molding compound, which process includes the steps of injection moulding, removal of the binder by heating, and sintering.

Abstract: The present invention relates to a novel method of manufacturing a composite body, such as a ZrB.sub.2 --ZrC--Zr composite body, by utilizing a post-treatment technique which may improve the oxidation resistance of the composite body. Moreover, the invention relates to novel products made according to the process. The novel process modifies at least a portion of a composite body by exposing said body to a source of second metal.

Abstract: A method of making a ceramic material by radiating a laser beam onto the portion of said ceramic material to be marked in a low oxygen atmosphere and a block gauge marked by this marking method. This marking method enables a ceramic material to have a distinct mark. A block gauge composed of a ceramic material has excellent properties such as corrosion resistance.

Abstract: Alkali corrosion resistant coatings and ceramic foams having superfine open cell structure are created using sol-gel processes. The processes have particular application in creating calcium magnesium zirconium phosphate, CMZP, coatings and foams.

Abstract: A composition suitable for the production of ceramics is provided. The composition comprises a particulate material which is a nitride, carbide, carbonitride or boride of Ti, Zr, Al, Si or B having a coating on the particle comprising 5 to 75 wt % with respect to particulate material of an oxide or hydrous oxide of zirconium.The composition can be used to produce a tough zirconia/non-oxide ceramic without the need to co-mill the ingredients.A stabilising agent for the zirconia may also be present in the coating although the invention is designed to avoid the necessity for such agents.Coating usually is effected by a wet treatment process in which the particles are dispersed in a solution of a hydrolysable zirconium salt and the oxide or hydrous oxide is coated on the particles by adjusting the pH of the dispersion.

Abstract: A method for manufacture of Group IVB metal carbide comprising a carbide of a metal selected from the group consisting of titanium, hafnium and zirconium ceramic composites is provided wherein a permeable mass of filler and carbon is contacted with a molten Group IVB metal. The molten metal is maintained in contact with the permeable mass for a sufficient period to infiltrate the permeable mass and to react the molten metal with the carbon source to form a Group IVB metal carbide composite. The permeable mass may comprise a Group IVB metal carbide, or other inert filler, or a combination of filler materials.

Abstract: A coated carbon fiber-reinforced composite material comprising a substrate material which comprises a carbon or ceramic matrix and reinforcing carbon fibers and a coating layer which comprises silicon carbide and at least one material selected from the group consisting of titanium carbide, zirconium carbide and hafnium carbide, wherein a part of the coating layer contacting to the substrate consists of at least one material selected from the group consisting of titanium carbide, zirconium carbide and hafnium carbide, a surface part of the coating layer consists of silicon carbide and a composition in an intermediate part between the part contacting to the substrate and the surface part continuously or stepwise changes from at least one material selected from the group consisting of titanium carbide, zirconium carbide and hafnium carbide to silicon carbide, and a carbon fiber-reinforced composite material comprising a matrix which comprises carbon and oxidation resistant ceramic and reinforcing carbon fiber co

Abstract: The invention relates to ceramic composite articles formed by infiltration of a particulate, permeable bed or permeable preform with a polycrystalline matrix produced as a metal-oxidant reaction product. The bed or preform includes a dross material.

Abstract: A heat resistive phosphate sintered body including a solid solution of R.sub.y Zr.sub.4 Si.sub.x P.sub.6-x O.sub.24 in which O.ltoreq.x.ltoreq.2, 2/3.ltoreq.y.ltoreq.2, R is a combination of one or more of cations having 2-3 valences, and x and y meet an electrically neutral condition, wherein a thermal expansion hysteresis loss is not more than 0.3%, and a dimensional change after a heat cycling in which heating and cooling are repeated between 100.degree. C. and 1,200.degree. C. at 100 times is not more than 1%. A process for producing such a heat resistive phosphate is also disclosed. The process includes the steps of preparing a batch mixture, as a starting material, of (ZrO).sub.2 P.sub.2 O.sub.7, ZrP.sub.2 O.sub.7, RO and/or a phosphate of R in which R is a combination of one or more of cations having two or three valences, and if necessary further SiO.sub.2, calcining, milling and shaping the thus prepared mixture, and firing the thus shaped body, wherein a calcining temperature is not less than 1,400.

Abstract: A process and related compositions for lowering the electrical resistivity of ZrB.sub.2 are described. In a preferred embodiment, ZrH.sub.2 or Zr powder is blended with the ZrB.sub.2 powder and the composite is vacuum hot pressed at 2100.degree. C. The elemental Zr so formed can be beneficial by gettering impurities such as oxygen, nitrogen, and carbon, and by altering the overall ZrB.sub.2 stoichiometry, e.g., to ZrB.sub.1.97. Excess Zr is present in the matrix as a finely dispersed material. A variety of dopant materials can also be used to alter the electrical, thermal, and mechanical properties. Samples exhibiting this Zr-rich second phase exhibit lower electrical resistivities, higher thermal conductivities, better thermal shock resistance.

Abstract: Ceramic bodies are bonded together via a layer of an oxidation reaction product of a molten metal, which metal is present in one or both of the ceramic bodies prior to bonding. At least one of the ceramic bodies comprises a ceramic product formed by the oxidation reaction of molten parent metal (e.g., alumina from molten aluminum) and grown as molten metal is transported through, and oxidized on the surface of, its own oxidation product. One or both of the ceramic bodies used in the bonding process contains surface-accessible channels of residual metal, i.e., metal channels which have resulted from molten-metal transport during the ceramic growth process. When the suitably assembled ceramic bodies are heated in the presence of an oxidant at a temperature above the melting point of the residual metal, molten metal at the surface of at least one of the ceramic bodies reacts with the oxidant to form a layer of oxidation reaction product, which may or may not incorporate at least one filler material.

Abstract: Self-supporting bodies are produced by reactive infiltration of a parent metal into a boron donor material and a carbon donor material. The reactive infiltration typically results in a composite comprising a boron-containing compound, a carbon-containing compound and residual metal, if desired. The mass to be infiltrated may contain one or more inert fillers admixed with the boron donor material and carbon donor material. The relative amounts of reactants and process conditions may be altered or controlled to yield a body containing a wide ranging varying volume percentage of ceramic, metal, and porosity.

Abstract: A heat resistive phosphate-zircon composite body including a main crystalline phase and a secondary crystalline phase, the main crystalline phase being a solid-solved phase of R.sub.y Zr.sub.4 Si.sub.x P.sub.6-x O.sub.24 in which 0<x<2, 2/3<y<2, and R includes of one or more kinds of bivalent or trivalent cations (provided that x and y satisfy electrical neutrality), and the secondary crystalline phase being zircon. A process for producing a heat resistive phosphate-zircon composite body is also disclosed. The process includes the steps of measuring and mixing given amounts of ZrP.sub.2 O.sub.7, (ZrO).sub.2 P.sub.2 O.sub.7, RO and/or a phosphate of R, SiO.sub.2 and a zircon powder, shaping the mixture and firing the shaped body, wherein the given amounts of ZrP.sub.2 O.sub.7, (ZrO).sub.2 P.sub.2 O.sub.7, RO and/or the phosphate of R, and SiO.sub.2 are measured such that the composite body may include a main crystalline phase composed of a solid-solved phase of R.sub.y Zr.sub.4 Si.sub.x P.sub.

Abstract: A refractory material possessing excellent erosion, thermal shock and oxidation resistance, as well as resistance to oxide build up useful in continuous casting of steel for use in such articles as tundish shrouds, particularly for slagline sleeves, bore liners and upper seating areas in such shrouds, as well as for stopper rod noses. The material consists of the following by weight: (a) carbon, from about 4% to about 50%; (b) one or more members selected from the group consisting of zirconium di-boride and titanium di-boride in an amount of from about 10% to about 90%; and (c) one or more members selected from the group consisting of zirconia, SiAlON, clay, alumina, magnesia, silica, silicon carbide, silicon nitride, boron nitride, mullite and chromia in an mount of from about 10% to about 80%.

Abstract: A refractory coating composition, adapted to be applied to a substrate by spraying or gunning, comprising:from about 25 to about 40% by weight alumina;from about 15 to about 25% by weight ceramic fiber;from about 40 to about 60% by weight colloidal silica; andsufficient water to form an aqueous suspension thereof.

Abstract: The present invention relates to a novel method of manufacturing a composite body, such as a ZrB.sub.2 -ZrC-Zr composite body, by utilizing a post-treatment technique which may improve the oxidation resistance of the composite body. Moreover, the invention relates to novel products made according to the process. The novel process modifies at least a portion of a composite body by exposing said body to a source of second metal.

Abstract: Improved inorganic ceramic papers comprising heterogeneous grades of ceramic fibers, namely small, high surface area fibers and at least one larger, lower surface area ceramic fiber are bonded into a matrix with the aid of an inorganic binder system having at least one metal oxide with an average particle size below 200 nm. Multiple different grades of inorganic ceramic fibers and small particle size inorganic binders impart good tensile strength and flexibility characteristics in the same sheet.

Abstract: Production of composite ceramic articles by infiltration of a particulate, permeable bed or permeable preform with a polycrystalline matrix produced as a metal-oxidant reaction product, wherein the bed or preform is comprised of dross.

Abstract: A cubic boron nitride-containing high-density inorganic composite is prepared by mixing cubic boron nitride with a powdered inorganic compound capable of forming a rigid sintered article having a density of at least 85% and a Vickers hardness of at least 800, which does not promote the conversion of cubic boron nitride into graphite-type phase boron nitride (hBN). The powder mixture is compressed into a mold, and fired at low pressure of between 1,000-2,000 MPa, at a temperature of not more than 1,500.degree. C., under which conditions the cubic boron nitride does not convert to hBN, but is sufficiently metastable to permit the formation of the high-density inorganic composite.

Abstract: There is disclosed a silicon nitride based sintered material which contains 0.1% to 20% by volume of zirconium oxide, 0.1% to 14% by volume of zirconium nitride, 3% to 15% by volume of a binder phase of an Mg-Si-O-N or Mg-Si-Zr-O-N system, and balance .beta.-silicon nitride. The sintered material may include an oxide layer of an average thickness of 10 to 1,000 .mu.m in a surface thereof and having a zirconium oxide concentration increasing toward the surface thereof. A process specifically adapted to manufacture the above sintered material is also disclosed.

Abstract: A heat resistant, low expansion phosphate compound and sintered bodies thereof, having a composition of RZr.sub.4 P.sub.6 O.sub.24 (R is one or more cations of IIa group in the periodic table, such as Ba, Sr and Ca): an average thermal expansion coefficient between room temperature and 1,400.degree. C. of -10.about.+10.times.10.sup.-7 /.degree.C.; and having a high temperature type crystalline structure having R3c symmetry at room temperature. The sintered body of the invention can be manufactured by mixing and shaping starting materials, firing the resulting shaped body at 1,400.degree. C..about.1,700.degree. C. to provide a sintered body with a composition of RZr.sub.4 P.sub.6 O.sub.24 and then, keeping the obtained sintered body at a high temperature of not lower than a temperature of phase transition between a high temperature type and a low temperature type crystalline structure, followed by quenching.

Abstract: Dense zircon refractories having improved thermal shock damage resistance for use in glass melt or high alkali vapor contact applications comprise, and, consist essentially of, about fifty percent by weight or more ZrSiO.sub.4, at least about one percent zirconia in particle form distributed substantially uniformly throughout the composition of the refractory, and optionally, a zircon grain growth enhancing composition, preferably TiO.sub.2.

Abstract: Compositions having the general formula (Ca.sub.x Mg.sub.1-x)Zr.sub.4 (PO.sub.4).sub.6 where x is between 0.5 and 0.99 are produced by solid state and sol-gel processes. In a preferred embodiment, when x is between 0.5 and 0.8, the MgCZP materials have near-zero coefficients of thermal expansion. The MgCZPs of the present invention also show unusually low thermal conductivities, and are stable at high temperatures. Macrostructures formed from MgCZP are useful in a wide variety of high-temperature applications. In a preferred process, calcium, magnesium, and zirconium nitrate solutions have their pH adjusted to between 7 and 9 either before or after the addition of ammonium dihydrogen phosphate. After dehydration to a gel, and calcination at temperatures in excess of 850.degree. C. for approximately 16 hours, single phase crystalline MgCZP powders with particle sizes ranging from approximately 20 nm to 50 nm result. The MgCZP powders are then sintered at temperatures ranging from 1200.degree. C. to 1350.

Abstract: An oxide type solid lubricant is made up of a sintered composite ceramic mass of Cr.sub.2 O.sub.3 and Na.sub.2 ZrO.sub.3 and has a Cr.sub.2 O.sub.3 content in the range of from 20 to 50% by weight.

Abstract: A process for producing a high density ceramic of perovskite represented by the formula:ABO.sub.

Abstract: Silicon nitride sintered bodies including Si.sub.3 N.sub.4 and at least one element selected from Y.sub.2 O.sub.3, MgO, ZrO.sub.2. In the silicon nitride bodies, a J phase solid solution is present in an intergranular phase, which satisfies a relation of 0.65x.ltoreq.y.ltoreq.x+2 wherein y is an amount of J phase solid solution and x is an amount of Y.sub.2 O.sub.3 as an additive.

Abstract: A method for manufacture of Group IVB metal carbide ceramic composites is provided wherein a permeable mass of filler and carbon is contacted with a molten Group IVB metal. The molten metal is maintained in contact with the permeable mass for a sufficient period to infiltrate the permeable mass and to react the molten metal with the carbon source to form a Group IVB metal carbide composite. The permeable mass may comprise a Group IVB metal carbide, or other inert filler, or a combination of filler materials.

Abstract: A composition suitable for use in the manufacture of a ceramic material comprises free-flowing substantially non-aggregated particulate zirconia. A substantial proportion of the zirconia is present in the tetragonal crystalline form and the particles of zirconia contain alumina in an amount of from 1 to 10% by weight expressed as Al on ZrO.sub.2. The particles are substantially free of silica.The particles of zirconia can be coated with an oxide or hydrous oxide of a stabilizing agent for zirconia such as an oxide or hydrous oxide of yttrium, calcium, magnesium, barium, strontium or cerium.An oxidation process is described for the manufacture of the tetragonal crystalline zirconia by the oxidation of zirconium halide in the presence of aluminium halide at high temperature in the vapor phase.

Abstract: A mold forming material contains 1-20% by weight of spodumene. Spodumene is a lithium mineral whose theoretical composition formula is Li.sub.2 O Al.sub.2 O.sub.3 4SiO.sub.2. If casting is performed using a mold forming material containing spodumene, a casting which is satisfactory in appearance and accuracy is obtained.

Abstract: In a method for producing ceramic body by oxidation of a parent metal having a graded microstructure characterized by a plurality of zones differing from each other in one or more properties by altering the process conditions during formation of said ceramic body such that a zone of the oxidation reaction product formed posterior to said altering has one or more properties different from a zone of the oxidation reaction product formed anterior to said altering.

Abstract: A composite comprised of a ceramic matrix and a plurality of layers of boron nitride coated fibrous material, said coated fibrous material comprising at least about 10% by volume of said composite, and said matrix having a thermal expansion coefficient which ranges from lower than that of said coated fibrous material to less than about 15% higher than that of said coated fibrous material.

Abstract: The invention relates to mixed sintered metal materials based on high-melting borides and nitrides and low-melting iron binder metals having the composition:(1) 40-97% by volume of borides, such as titanium diboride and zirconium diboride;(2) 1-48% by volume of nitrides, such as titanium nitride and zirconium nitride;(3) 0-10% by volume of oxides, such as titanium oxide and zirconium oxide, with the proviso that components (2) and (3) may also be present as oxynitrides such as titanium and zirconium oxynitride; and(4) 2-59% by volume of low-carbon binder metals, such as iron and iron alloys and to processes for preparing the same.

Abstract: A cubic boron nitride-containing high-density inorganic composite sintered article is produced by a method which essentially consists of preparing a mixture of a cubic boron nitride powder with an inorganic compound powder capable of forming a high-rigidity sintered article under the conditions permitting the cubic boron nitride to remain in a substantially metastable, though not thermodynamically stable, state, a mixture of an inorganic compound-coated cubic boron nitride powder with an inorganic compound powder, or an inorganic compound-coated cubic boron nitride powder, and sintering the mixture of the cubic boron nitride powder with an inorganic compound powder, the mixture of the inorganic compound-coated cubic boron nitride powder with an inorganic compound powder or an inorganic compound-coated cubic boron nitrides powder, under the conditions of not more than 2,000 MPa of pressure and not more than 1,500.degree. C.

Abstract: A preparation method for zircon powder, which comprises heating a feed powder mixture comprising:(1) silica and zirconia obtained by subjecting a liquid having a pH of not higher than 8 and containing silica and zirconia in a SiO.sub.2 /ZrO.sub.2 molar ratio of substantially 1/1, to liquid-removing treatment, and(2) zircon in an amount of at least 0.1% by weight based on the total amount of said silica and zirconia,at a heating rate of not higher than 5.degree. C./min from 1,200.degree. C. to a calcination temperature, and maintaining it at a calcination temperature of from 1,300.degree. to 1,700.degree. C. for from 1.0 to 24 hours.

Abstract: Ceramic powders selected from the group (a) consisting of ZrB.sub.2, HfB.sub.2, ZfC, ZrN and HfN and ceramic powders selected from the group (b) consisting of TiC, TiN and TiO.sub.2 are mixed, the mixture is sintered in a non-oxidizing atmosphere, a substitution reaction of chemical elements between the compound of the ceramic powders of the group (a) and the compound of the ceramic powders of the group (b) is caused in the sintering, and a ceramic composite substantially comprising compounds which do not belong to the groups (a) and (b) is produced by the substitution reaction. By this process, the affection of the particle size and the aggregation of raw powders to the sintering can be greatly reduced, the ranges of the applicable sintering conditions can be broadened, and dense ceramic composites having fine crystal grains and having excellent mechanical properties can be obtained.

Abstract: The invention relates to refractory materials.It relates to a refractory product without cracks obtained by fusion under oxidizing conditions and cast from a mixture of starting materials such that the product obtained has the average chemical composition by weight, in % by weight based on the following oxides:______________________________________ ZrO.sub.2 >92 SiO.sub.2 2-6.5 Na.sub.2 O 0.12-1.0 Al.sub.2 O.sub.3 0.4-1.15 Fe.sub.2 O.sub.3 + TiO.sub.2 <0.55 P.sub.2 O.sub.5 <0.05. ______________________________________Use in the glassmaking sector.

Abstract: The present invention relates to ceramic bodies suitable for use in high temperature applications such as molten metal filters and kiln furniture. The ceramic bodies are formed from partially stabilized zirconia and are characterized by the presence of from about 12% to about 80% by weight zirconia in a monoclinic phase and the balance essentially in a cubic phase at room temperature. The ceramic bodies possess an excellent combination of physical properties including high temperature strength and thermal shock resistance. The invention also relates to the process for forming the ceramic bodies and the thixotropic ceramic slurry used therein.

Abstract: A process for the production of a precursor which is a polymeric material comprising at least one metallic or non-metallic element, oxygen and carbon and from which a ceramic material, e.g. a carbide, nitride, boride, or silicide, may be produced by pyrolysis, which process comprises reacting(1) a first reactant which comprises a compound or compounds of at least one metallic or non-metallic element having two or more groups reactive with hydroxyl groups, and(2) a second reactant which comprises at least one organic compound having two or more hydroxyl groups,said reaction being effected in a liquid medium in which the reactants are soluble and/or dispersible and in which the polymeric material which is produced by the reaction is insoluble or in which the polymeric material may be caused to be insoluble, precipitating the polymeric material in the liquid medium in particulate form, and recovering the polymeric material from the liquid medium in particulate form.

Abstract: Zirconyl phosphate ceramics having high strength and high heat shock resistance, which consist essentially of at least 99% by weight of zirconyl phosphate, zirconium phosphates or both and no other phase material in quantities of more than 1% by weight are useful in ceramic filters and ceramic internal combustion engine parts and are prepared by mixing zirconyl phosphate or substances which form zirconyl phosphate with an antimony compound, moulding the resulting mixture and then sintering the moulded mixture at temperatures of 1200.degree. to 1700.degree. C.

Abstract: An auxiliary nozzle for a loom, such as an air jet loom within a shuttleless loom, jets pressurized gas in order to prevent stall of weft inserted into warp shedding. At least a tip portion of an auxiliary nozzle body is formed of ceramics material having a very small integrally-molded surface roughness of 0.5 .mu.m or less and having characteristics of high toughness and high strength whereby occurrence of flaws in warp can be minimized and woven fabric of high quality can be obtained. Particularly, by employment of particular zirconia-type ceramics, the moldability, processing properties for drilling and wear resistance can be improved.

Abstract: The invention relates to ceramic composite articles formed by infiltration of a particulate, permeable bed or permeable preform with a polycrystalline matrix a metal-oxidant reaction product. The bed or preform includes a dross material.

Abstract: A ceramic implant comprising a sintered body of zirconia and a coating layer of a porous sintered body of a mixture comprising .alpha.-tricalcium phosphate and zirconia, or hydroxyapatite and zirconia formed on the surface of the sintered body of zirconia.

Abstract: A ceramic article made from a mixture comprising (on a dry weight basis) magnesium oxide (MgO) in an amount up to 2% by weight, a defined rare earth oxide in amount up to 10% by weight, balance beryllium oxide, and trace elements, the defined rare earth oxide being zirconium oxide (ZrO.sub.2), hafnium oxide (HfO.sub.2), cerium oxide (Ce.sub.2 O.sub.3), yttrium oxide (Y.sub.2 O.sub.3), ytterbium oxide (Yb.sub.2 O.sub.3) or thorium oxide (ThO.sub.2). Such ceramic articles have much improved properties in particular higher densities than attainable hitherto and better crossbreak strength and surface smoothness as fired. The ceramic compositions can also be admixed with supplementary ceramic materials such as silicon carbide to produce microwave absorbing materials.

Abstract: A ternary ceramic alloy which produces toughening of zirconia and zirconia composites through the stress transformation from tetragonal phase to monoclinic phase. This alloy, having the general formula Ce.sub.x Hf.sub.y Zn.sub.1-x-y O.sub.2, is produced through the addition of appropriate amounts of ceria and hafnia to the zirconia. Typically, improved toughness is achieved with about 5 to about 15 mol % ceria and up to about 40 mol % hafnia. The preparation of alloys of these compositions are given together with data as to the densities, tetragonal phase content, hardness and fracture toughness. The alloys are useful in preparing zirconia bodies as well as reinforcing ceramic composites.

Abstract: Heat-resisting phosphate based compound sintered bodies are disclosed, which each contain not less than 10% by weight of a crystalline phase of RZr.sub.4 (PO.sub.4).sub.6 in which R is an element in Group IIa of the Periodic Table. A weight-reduced percentage of the sintered body when being thermally treated at 1,400.degree. C. for 100 hours is not more than 10%. A process for producing such phosphate based compound sintered bodies is also disclosed.

Abstract: Ceramic bodies are bonded together via a layer of an oxidation reaction product of a molten metal, which metal is present in one or both of the ceramic bodies prior to bonding. At least one of the ceramic bodies comprises a ceramic product formed by the oxidation reaction of molten parent metal (e.g., alumina from molten aluminum) and grown as molten metal is transported through, and oxidized on the surface of, its own oxidation product. One or both of the ceramic bodies used in the bonding process contains surface-accessible channels of residual metal, i.e., metal channels which have resulted from molten-metal transport during the ceramic growth process. When the suitably assembled ceramic bodies are heated in the presence of an oxidant at a temperature above the melting point of the residual metal, molten metal at the surface of at least one of the ceramic bodies reacts with the oxidant so to form a layer of oxidation reaction product which may or may not incorporate at least one filler material.

Abstract: A method of manufacturing ceramic powders having the perovskite structure by means of a reaction in an aqueous solution, in which a homogeneous aqueous solution comprising a strong organic base and comprising at least one alkaline-earth metal salt and at least one zirconium salt and/or at least one titanium salt is converted at a reaction temperature in the range from 70.degree. to 150.degree. C., and water adhering to the reaction product is removed, or in which an alkaline-earth metal-titanium-acetate gel having a strong organic base is converted at a reaction temperature in the range from 110.degree.-180.degree. C., and water adhering to the reaction product is removed.

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 process for the production of a refractory compound, e.g. a carbide or nitride, of a metallic or non-metallic element, by reacting a mixture of a compound of the metallic or non-metallic element having at least two groups reactive with hydroxyl groups and an organic compound having at least two hydroxyl groups to produce an oxygen-containing polymeric product, and pyrolysing the polymeric product, e.g. in an inert atmosphere to produce a carbide or in an atmosphere of reactive nitrogen compound to produce a nitride, in which the reaction mixture contains an aluminium compound containing at least one group reactive with hydroxyl groups.The presence of the aluminium compound in the reaction mixture leads to an increase in the proportion of carbon in the product initially produced by pyrolysis, and to a higher purity in the refractory compound which is ultimately produced.