Abstract: There is provided a novel thermal barrier coating material which does not have a problem of phase transition, whose melting point is higher than its working temperature range, whose thermal conductivity is smaller than that of zirconia, and whose thermal expansion coefficient is greater than that of zirconia. The thermal barrier coating material comprises as a main component, a composition having an orthorhombic or monoclinic structure derived from perovskite (for example, a tabular perovskite structure expressed by the composition formula A2B2O7), or a tetragonal layer structure having a c axis/a axis ratio equal to or greater than 3 (for example, a K2NiF4 structure, a Sr3Ti2O7 structure, or a Sr4Ti3O10 structure), a composition expressed by the composition formula LaTaO4, or a composition having an olivine type structure expressed by the composition formula M2SiO4 or (MM?)2SiO4 (where M, M? are divalent metal elements).

Abstract: The disclosure relates to metal oxide powders with a bimodal particle size distribution, to ceramics that can be made from these metal oxide powders, especially milling ceramics for use in dental technology, to a method for the production of the metal oxide powders and of the ceramics, to the use of nanoscale metal oxide powders for the production of the metal oxide powders and of the ceramics as well as to dental ceramic products.

Abstract: A ceramic filter is provided, including a base body having partition walls made of a ceramic porous body and defining cells, filter membranes provided on the partition walls which are made of a ceramic porous body having an average pore diameter smaller than that of the surface of each partition wall, and a glass seal provided to cover at least the end face of the base body. The glass seal includes an alkali-free glass containing silica (SiO2) in an amount of 55 to 65 mol %, zirconia (ZrO2) in an amount of 1 to 10 mol % and at least one kind of alkaline earth metal oxide selected from calcia, baria and strontia, but which does not substantially contain zinc oxide.

Abstract: A method for manufacturing barium zirconate particles includes providing a mixture of materials that includes barium, zirconium and a sintering aid, wherein the sintering aid includes at least one of barium tungstate, potassium niobate, tungsten oxide, barium molybdate, molybdenum oxide, potassium tantalate, potassium oxide, sodium niobate, sodium tantalate, sodium oxide, lithium niobate, lithium tantalate, lithium oxide, copper oxide, manganese oxide, zinc oxide, calcium zirconate and strontium zirconate; and heating the mixture of materials to produce barium zirconate particles that include the sintering aid.

Abstract: In dental ceramics containing zirconium dioxide and silicon-dioxide with a Zr/Si ratio of between 0.5 and 1.0, 1 to 12 wt % of aluminum oxide and up to 2 wt % of an alkali- or earth alkali metal oxide, those materials are selectively mixed with yttrium-stabilized zirconium dioxide with a Zr/Si ratio of the mixture being between 0.5 and 1 wt % and also a silicon organic compound as well as a compression aid, and a green body is formed from the mixture by milling, which green body is then sintered.

Abstract: A high-zirconia cast refractory material which contains 85-95 wt % of ZrO2, 4-12 wt % of SiO2, 0.1 to less than 0.8 wt % of Al2O3, less than 0.04 wt % of Na2O, 0.01-0.15 wt % of K2O, 0.1-1.5 wt % of B2O3, 0.01-0.2 wt % of CaO, less than 0.4 wt % of BaO, less than 0.2 wt % of SrO, 0.05-0.4 wt % of Y2O3, and 0.3 wt % or less of Fe2O3 and TiO2 together, but does not substantially contain CuO and P2O5 (less than 0.01 wt %), such that the molar ratio of the glass-forming oxides (such as SiO2 and B2O3) to the glass-modifying oxides (such as Na2O, K2O, CaO, MgO, SrO, and BaO) is 20-100, said refractory material having an electric resistance being 200 ?·cm or higher after standing for 12 hours at 1500° C.

Abstract: The invention relates to vitreous compositions, in particular of the vitroceramic type, transparent to infrared, production and uses thereof. Said compositions comprise in mol. %: Ge 5-40, Ga<1, S+Se 40-85, Sb+As 4-40, MX 2-25, Ln 0-6, adjuncts 0-30, where M=at least one alkaline metal, selected from Rb, Cs, Na, K and Zn, X=at least one atom of chlorine, bromine or iodine, Ln=at least one rare earth and adjunct=at least one additive comprising at least one metal and/or at least one metal salt with the sum of all molar percentages of the components present in said composition being 100.

Abstract: A coated plastic substrate module (100) includes a plastic substrate (110), an organic coating (130), and a modulating film (120) sandwiched therebetween. The modulating film is made from partially stabilized zirconia. A method for manufacturing a coated plastic substrate module includes the following steps: providing a plastic substrate; forming a modulating film on the plastic substrate, the modulating film being made from partially stabilized zirconia; forming an organic coating on the modulating film; and annealing the treated plastic substrate having the modulating film and organic coating.

Abstract: A primary sintered body having a density of 95 % or more obtained by sintering a zirconia powder comprising an yttria main component as a stabilizer under ordinary pressure is set in a vessel of a semi-sealed state and subjected to HIP treatment (secondary sintering) at a temperature of from 1,600 to 1,900° C. under a pressure of 50 MPa or higher, and according to need, heated treated in an oxidizing atmosphere, thereby producing a polycrystalline sintered body of zirconia having high transparency of an in-line transmission of 50% or higher.

Abstract: [Problems to be Solved] To provide a production method of an alkaline zirconia having compatibility of particle properties and binding properties. [Means to Solve the Problems] A production method of an alkaline zirconia sol including: a process (I) in which an alkaline zirconia sol (A) is mixed with a basic zirconium carbonate salt (B1), the alkaline zirconia sol (A) being obtained by: a sub-process (i) in which a zirconium salt (B2) is heated at 60 to 110° C. in an aqueous medium containing a carbonate salt of quaternary ammonium; and a sub-process (ii) in which a hydrothermal treatment is performed at 110 to 250° C. following the sub-process (i). More specifically, a production method of an alkaline zirconia sol including: a process (I) in which an alkaline zirconia sol (A) and a basic zirconium carbonate salt (B1) are mixed in a mass ratio (Bs/As) ranging from 0.05 to 4.

Abstract: Abradable coatings are provided. The coatings comprise SrTiO in combination with a ceramic, such as ytrria stabilized zirconia, or SrTiO in combination with an MCrAlX, such as NiCoCrAlY. The abradable coatings are suitable for use in high temperature environments found in gas turbine engines. Also provided are metal articles coated with such coatings, and abradable assemblies.

Abstract: A formation of internally nucleated glass ceramics articles that can be heated in the 1350-1450° C. range for extended periods of time without significant deformation or change in shape is disclosed. The predominant crystal phase of these glass ceramics is celsian (BaAl2Si2O8) or its strontium equivalent (SrAl2Si2O8), or solid solutions or mixtures of these compositions, all belonging to the feldspar mineral group.

Abstract: A ceramic consisting essentially of: about 51% to about 68% by weight ZrO2; about 20% to about 40% by weight Al2O3; about 9% to about 12% by weight CeO2; about 0.05% to about 0.2% by weight SiO2; about 0.01% to about 0.1% by weight MgO; about 0.1% to about 0.6% by weight MnO; and about 0.01% to about 0.8% by weight CaO.

Abstract: There is described a ceramic powder, ceramic layer and layer system having gadolinium/mixed crystal 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 according to the invention has an outer ceramic layer, which comprises a mixed crystal of gadolinium zirconate and gadolinium hafnate.

Abstract: The invention relates to a refractory ceramic product which comprises: a) ?93% by weight of at least one refractory basic component and b) ?7% by weight of at least one anticorrosive component from the group including: b1) transition metals, b2) compounds of transition metals with each other, b3) non-oxidic compounds of transition metals, b4) oxidic compounds of transition metals, b5) compounds of the transition metals with Ca, Ba, Sr.

Abstract: A jig for calcining an electronic component including a substrate 11 and a zirconia layer 12 coated on a surface of the substrate characterized in that the zirconia layer including one or more metal oxides forming a liquid phase is calcined for improving peel-off resistance and wear resistance to crystallize the liquid phase after the calcination. In the jig for calcining the electronic component, when the zirconia layer is formed by using an inexpensive method such as an application method, the zirconia layer is not peeled off from the substrate, and grains are not detached.

Abstract: This invention relates to thermally sprayed coatings of a high purity yttria or ytterbia stabilized zirconia powder, said high purity yttria or ytterbia stabilized zirconia powder comprising from about 0 to about 0.15 weight percent impurity oxides, from about 0 to about 2 weight percent hafnium oxide (hafnia), from about 6 to about 25 weight percent yttrium oxide (yttria) or from about 10 to about 36 weight percent ytterbium oxide (ytterbia), and the balance zirconium oxide (zirconia). Thermal barrier coatings for protecting a component such as blades, vanes and seal surfaces of gas turbine engines, made from the high purity yttria or ytterbia stabilized zirconia powders, have a density greater than 88% of the theoretical density with a plurality of vertical macrocracks homogeneously dispersed throughout the coating to improve its thermal fatigue resistance.

Abstract: A gasifier internal refractory coating has at least one region of a sintered material containing at least 45% by weight of chromium oxide (Cr2O3) and at least 1% by weight of zirconium oxide, at least 20% by weight of the zirconium oxide (ZrO2) being stabilized in the cubic and/or quadratic form.

Abstract: Zirconia-containing ceramic compositions that are capable of providing thermal barrier coatings wherein the zirconia is stabilized in the cubic crystalline phase. These compositions comprise at least about 50 mole % zirconia and a stabilizing amount up to about 49 mole % of a stabilizer component comprising: (1) a first metal oxide selected from the group consisting of ytterbia, neodymia, mixtures of ytterbia and neodymia, mixtures of ytterbia and lanthana, mixtures of neodymia and lanthana, and mixtures of ytterbia, neodymia and lanthana in an amount of from about 5 to about 49 mole % of the composition; and (2) a second metal oxide selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india and mixtures thereof in an amount of about 4 mole % or less of the composition. The ceramic composition further comprises one or more of a third metal oxide selected from the group consisting of: (a) hafnia in an amount from about 0.

Abstract: Compositions, and articles having low thermal expansion suitable for high temperature applications, such as automotive exhaust treatment and method of manufacturing such articles are disclosed.

Abstract: A refractory brick, comprised of a refractory material having about 55% to about 96% by weight magnesia particles or magnesia particles containing spinel precipitates, about 3% to about 20% by weight fine zirconia particles having a particle size less than 35 Tyler mesh (less than 425 ?m), and about 1% to about 25% of a material selected from the group consisting of coarse zirconia, coarse spinel, coarse alumina-zirconia, and combinations thereof.

Abstract: A ceramic includes alumina in an amount between about 90 and about 99% by weight, a zirconium containing compound in an amount between about 0 and about 1% by weight, and an oxide mixture in an amount between about 1 and about 10% by weight. The oxide mixture includes a glass former and a network modifier, wherein the molar ratio of the glass former to the network modifier ranges between about 0.8:1 and 1.2:1. The ceramic insulator is particularly adapted for use as an insulator in a spark plug to provide improved dielectric strength and shunt resistance of greater than one 1000 megaohms at 1000 degrees Fahrenheit, so as to reduce the shunting of the spark plug and thereby improve the quality of the spark generated by the spark plug.

Abstract: Alumina/zirconia ceramics containing Al2O3 in an amount of not less than 65 mass % and ZrO2 in an amount of 4 to 34 mass %, and further containing TiO2, MgO and SiO2. The ceramics effectively suppresses the growth of shape isotropic particles of alumina, suppresses the growth of zirconia particles, and has a high strength and a high hardness. Besides, the ceramics containing SrO features a high fracture toughness.

Abstract: The invention concerns a refractory product comprising more than 85% of zirconia (ZrO2), characterized in that it comprises in wt. % with respect to oxides: ZrO2>92%, SiO2: 2 to 8%, Na2O: 0.12 to 1%, Al2O3: 0.2 to 2%, 0.5%?Y2O3+CaO?2.6%, with the proviso that Y2O3: 0.3 to 2% and that CaO: 0.5 to 1.93%.

Abstract: Aspects of the present invention may be found in an electrostatic dissipative ceramic component having a stabilized zirconia base, a surface resistivity between 1×105 and 1×1012 ohms per square and at least 2 percent by volume scattering material. The stabilized zirconia may be present in amounts between 60 and 95 weight percent. Further aspects of the invention may be found in an electrostatic dissipative ceramic material having stabilized zirconia, a resistivity modifier, and a scattering material. The stabilized zirconia may be present in amounts between 60 and 95 weight percent of the ceramic material. The resistivity modifier may be present in amounts between 5 and 30 weight percent. The scattering material may comprise at least 2 volume percent of the electrostatic dissipative ceramic material. The component may be used in the manufacturing of electronic component such as hard drives.

Abstract: A material having a negative or low thermal expansion coefficient and composed substantially of a single crystal system is provided. The material is an oxide represented by the chemical formula ((R4+M2+)1-xA3+2x)(QO4)3 (where R stands for at least one tetravalent metal element selected from Zr and Hf; M stands for at least one divalent metal element selected from Mg, Ca, Sr, Ba, and Ra; Q stands for at least one hexavalent metal element selected from W and Mo; and A stands for at least one trivalent metal element selected from Al, Sc, Y, Lu, Ga, and In; 0<x<1) and composed substantially of a single crystal system.

Abstract: It is a principal object of the present invention to provide low thermal expansion materials able to answer to the needs of various uses. The present invention relates to low thermal expansion materials constituted substantially from a crystalline body represented by a compositional formula RM(QO4)3, wherein R represents at least one selected from Zr and Hf, M represents at least one selected from Mg, Ca, Sr, Ba and Ra, and Q represents at least one selected from W and Mo.

Abstract: Glass for a light filter capable of preventing variation of refractive index in a band-pass filter has a coefficient of thermal expansion within a range from 90×10?7/° C. within a temperature range from ?20° C. to +70° C. and, preferably, Young's modulus of 75 GPa or over and Vickers hardness of 550 or over, and light transmittance for plate thickness of 10 mm of 90% or over within a wavelength range from 950 nm to 1600 nm.

Abstract: The invention relates to a fired refractory ceramic molded piece with a spinel matrix based on (Mg)2+ (Al, Cr)23+O4, in which coarser particles based on chromium corundum and/or corundum and coarser particles based on ZrO2 are present.

Abstract: Ceramic compositions comprising at least about 91 mole % zirconia and up to about 9 mole % of a stabilizer component comprising a first metal oxide having selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india and mixtures thereof. This stabilizer component further comprises a second metal oxide of a trivalent metal atom selected from the group consisting of lanthana, gadolinia, neodymia, samaria, dysprosium, and mixtures thereof and a third metal oxide of a trivalent metal atom selected from the group consisting of erbia, ytterbia and mixtures thereof. These ceramic compositions are useful in preparing thermal barrier coatings having reduced thermal conductivity for the metal substrate of articles that operate at, or are exposed to, high temperatures.

Abstract: Aspects of the present invention may be found in an electrostatic dissipative ceramic component having a stabilized zirconia base, a surface resistivity between 1×105 and 1×1012 ohms per square and at least 2 percent by volume scattering material. The stabilized zirconia may be present in amounts between 60 and 95 weight percent. Further aspects of the invention may be found in an electrostatic dissipative ceramic material having stabilized zirconia, a resistivity modifier, and a scattering material. The stabilized zirconia may be present in amounts between 60 and 95 weight percent of the ceramic material. The resistivity modifier may be present in amounts between 5 and 30 weight percent. The scattering material may comprise at least 2 volume percent of the electrostatic dissipative ceramic material. The component may be used in the manufacturing of electronic component such as hard drives.

Abstract: A ceramic sheet has a burr height on the periphery of the sheet of ±100 ?m or less and/or a dimple height on the sheet surface of 100 ?m or less, as determined by irradiating the sheet with a laser beam to measure reflected light, and three-dimensionally analyzing the reflected light with a laser optical three-dimensional profiling instrument. This sheet is highly resistant to stacking-induced loads and thermal stresses. Further, when the ceramic sheet includes a zirconia ceramic partially stabilized with 2.8 to 4.5% by mole of yttria and containing 0.1 to 2% by mass of at least one dispersed reinforcing oxide, in which the grain size of the surface of the sheet has an average of 0.1 to 0.4 ?m, a maximum of 0.4 to 0.8 ?m, and a coefficient of variation of 30% or less, which grain size is determined by scanning electron microscopic observation, the ceramic sheet has satisfactory strength at room temperature and at high temperatures and satisfactory durability of strength at high temperatures.

Abstract: The proposed material consists of zirconium dioxide crystallites of tetragonal modification of acicular or platy form, having a size not exceeding 0.05 mm, oriented parallel to their long axes and forming a rectangular lattice. Such a structure of the material insures its increased resistance to the onset of cracking, this promoting high physico-mechanical characteristics of the material. The material is obtained under the conditions of lowered pressure by the method of melting in a cold container with its horizontal moving relative to an inductor. The physico-mechanical properties of the material make it possible to manufacture therefrom extremely sharp scalpels, which ensure the blade service life of up to 60 operations on dense tissues, the blades withstanding up to 10 resharpenings without changes in the blade profile.

Abstract: Thermal spray powders suitable for application of a thermal barrier coating on a substrate can be obtained by plasma spraying a chemically homogeneous zirconia stabilized in the tetragonal form using a stabilizing oxide such as yttria to obtain a powder comprising substantially spherical hollow zirconia particles with sizes less than about 200 micrometers.

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: The object of the present invention is to provide a ceramic body that can support a required amount of a catalyst component, without lowering the characteristics such as strength, being manufactured without forming a coating layer and providing a high performance ceramic catalyst that is excellent in practical utility and durability. A noble metal catalyst is supported directly on the surface of the ceramic body and the second component, consisting of compound or composite compound of element having d or f orbit in the electron orbits thereof such as W, Co, Ti, Fe, Ga and Nb, is dispersed in the first component made of cordierite or the like that constitutes the substrate ceramic. The noble metal catalyst can be directly supported by bonding strength generated by sharing the d or f orbits of the second component, or through interaction with the dangling bond that is generated in the interface between the first component and the second component.

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: 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 pre-alloyed stabilized zirconia powder suitable for use in thermal barrier applications is formed by alloying zirconia with a stabilizer, such as yttria, and processing the alloyed stabilized zirconia to form a very fine powder. The raw powder is then spray-dried to produce an agglomerated powder having an average particle size suitable for use in spray coating applications. The resulting powder can be used in a thermal-spray application to produce a porous thermal barrier coating having a substantially decreased thermal conductivity when compared to conventional TB coatings, such those produced using plasma-densified powders.

Abstract: A zirconia sintered body having high strength and high toughness is provided, and a method for producing the same is also provided. The zirconia sintered body comprising tetragonal zirconia, wherein a full width at half maximum at (111) plane of the tetragonal zirconia obtained by X-ray diffraction pattern is from 0.38 to 4 degree. A method for producing the zirconia sintered body, wherein the method comprises steps of; molding zirconia powder having an average particle diameter of from 0.1 to 0.6 &mgr;m, a maximum particle diameter of 5 &mgr;m or less and a substantially polyhedral shape, and then sintering the molded green body under the temperature of from 1200 to 1400° C.

Abstract: A crucible material whose chemical composition consists essentially of, in weight %, about 93.5% to about 97.5% ZrO2, about 0.2% to about 1.0% MgO, about 1.0% to about 3.0% SiO2, and about 1.5% to about 2.5% Y2O3 wherein the SiO2 can be present as silica and a silicate of zirconium, magnesium, and/or yttrium. When formed to a crucible shape and sintered (fired) at elevated temperature, the ceramic material provides a crucible with improved resistance to thermal shock when heated to over 1100 degrees C.

Abstract: The present invention provides the sanitary ware for which it is possible to accurately design the shapes and dimensions of the products after being subjected to firing while maintaining the mechanical strength required to sanitary ware, degradation of the process yield caused by shrinkage and deformation scarcely occurs, and the setting efficiency and productivity are improved as compared to the prior art. The sanitary ware of the present invention is the sanitary ware which includes a ceramic body and a glaze layer formed on the desired portions of the body surface, and is characterized in that the CaO component segregation portions in which portions the CaO component is segregated are dispersed in the body.

Abstract: A high strength ceramic body and a method of making same are disclosed. The ceramic body is formed of ceramic composition containing 2.8-5.0% by weight MgO, an effective amount of grain growth inhibiting material, and the balance being essentially zirconia. The crystalline microstructure of the ceramic body comprises grains of cubic zirconia having an average grain size of less than about 30 microns in major dimension, 0.1-8.7% by volume of discrete particles of the grain growth inhibiting material, and precipitates of tetragonal zirconia having a substantially ellipsoidal shape with a long dimension of about 0.1-0.4 microns.

Abstract: Disclosed is a dielectric ceramic composition represented by (1−x)(Mg1/3Ta2/3)O2-xZrO2(0≦x≦0.2) that has high dielectric constants, high quality factor (Q) values, and stable temperature coefficients of the resonant frequency. The composition can easily achieve a high quality factor (Q) value by sintering for a lesser duration and at lower temperatures.

Abstract: Abrasive particles and methods of making abrasive particles are disclosed. The abrasive particles may be incorporated into a variety of abrasive articles, including bonded abrasives, coated abrasives, nonwoven abrasives, and abrasive brushes.

Abstract: Fused abrasive particles comprising eutectic material comprising Al2O3—MgO-REO eutectic. The fused abrasive particles can be incorporated into abrasive products such as coated abrasives, bonded abrasives, non-woven abrasives, and abrasive brushes.

Abstract: A ceramic bearing ball in which at least a portion of a constituent ceramic is formed of an electrically conductive inorganic compound phase, whereby a proper electrical conductivity is imparted to the ceramic. Thus, electrifying of a bearing ball is prevented or effectively suppressed. This prevents the problem involved in production of balls of small diameter wherein such balls adhere to an apparatus (e.g., a container) during production thereof, thus hindering smooth progress of the production process. In addition, when ceramic balls are used in precision electronic equipment, such as a hard disk drive of a computer, which is operated at high rotational speed, adhesion of foreign substance due to electrification of the balls, and resultant generation of abnormal noise or vibration can be prevented or effectively suppressed.

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: Rare-earth alloy is cast into a sheet (6) or the like by using a tundish (3, 13). The refractory material of the tundish used for casting does not necessitate preheating for improving the flowability of the melt (2). The refractory material used essentially consists of 70 wt % or more of Al2O3 and 30 wt % or less of SiO2, or 70 wt % or more of ZrO2 and 30 wt % or less of one or more of Y2O3, Ce2O3, CaO, MgO, Al2O3, TiO2 and SiO2. The refractory material has 1 g/cm3 or less of bulk density, has 0.5 kca/(mh° C.) or less of thermal conductivity in the temperature range of from 1200 to 1400° C., and has 0.5 wt % or less of ratio of ignition weight-loss under the heating condition of 1400° C. for 1 hour.

Abstract: Oxidized alumina-zirconia-silica (AZS) refractories containing 40 wt % to 55 wt % Al2O3, 32 wt % to 45 wt % ZrO2, 10 wt % to less than 16 wt % SiO2 and 1 wt % to 3 wt % of an alkali metal oxide selected from Na2O, K2O and mixtures thereof have a microstructure essentially comprising alpha-alumina crystals, free zirconia crystals, eutectic crystals and an intercrystalline vitreous phase. At least in an active area, more than 20% by number of the free zirconia crystals have a dendritic shape and are interleaved with each other and with eutectic crystals and at least 40% by number of the dendritic free zirconia crystals have a dimension greater than 300 &mgr;m.