Abstract: A refractory composition that is highly resistant to siliceous slag comprising from 45-85 weight percent chromic oxide and 15-55 weight percent alumina, said composition having a coarse grain fraction of -4 mesh and a fine grain fraction of -325 mesh comprising 40-100 weight percent chromic oxide.

Abstract: A refractory composition for use in contact with molten aluminum alloys containing a refractory aggregate, a binder and 9Al.sub.2 O.sub.3.2B.sub.2 O.sub.3. The aluminum borate may be of the type produced as a by-product in the production of ferro-boron alloys and known as aluminum boron slag.

Abstract: Vibratable, monolithic refractory mixes useful to form linings for receptacles and related apparatus components used to handle or treat molten metal, such as ladles, tundishes, troughs and runners, including novel binders therefor.

Abstract: There is disclosed a material for hot or plasma spraying, especially a material based on oxide ceramics, and a process for the production thereof. The composition of the invention is a mixture of powdered oxides containing at least two fundamental oxides with high melting point, and at least one glass-forming oxide the melting point of which is lower. The invention also includes a process for the production of such composition by the melting and agglomeration of individual components in the oxidizing medium of a plasma stream, including the special treatment of the starting components.

Abstract: Several methods are set forth for preparing polymetallic spinels by coprecipitating two or more metal compounds in a proportion to provide a total of eight positive valences when combined in the oxide form in the spinel crystal lattice. The methods disclosed require coprecipitation of the metals in the hydroxide form or convertible to the hydroxide-oxide form, calcining the coprecipitate, and finally sintering the calcined material at about one-half its melting point or greater, thereby forming a spinel which has a density of greater than 50 percent of the theoretical density of spinel crystal. Also disclosed are techniques for preparing spinels having more than two metals incorporated into the spinel lattice, as well as a separate oxide phase associated with the spinel crystallites, and slipcasting compositions.

Abstract: This invention is a new process for producing refractory crystalline oxides having improved or unusual properties. The process comprises the steps of forming a doped-metal crystal of the oxide; exposing the doped crystal in a bomb to a reducing atmosphere at superatmospheric pressure and a temperature effecting precipitation of the dopant metal in the crystal lattice of the oxide but insufficient to effect net diffusion of the metal out of the lattice; and then cooling the crystal. Preferably, the cooling step is effected by quenching. The process forms colloidal precipitates of the metal in the oxide lattice. The process may be used, for example, to produce thermally stable black MgO crystalline bodies containing magnetic colloidal precipitates consisting of about 99% Ni. The Ni-containing bodies are solar-selective absorbers, having a room-temperature absorptivity of about 0.96 over virtually all of the solar-energy spectrum and exhibiting an absorption edge in the region of 2 .mu.m.

Abstract: A highly densified chromium oxide-based sintered body is produced by heating a powder mixture of chromium sesquioxide and at least one substance selected from silica, zirconia and zircon in a carbon powder. The highly densified chromium oxide-based sintered body has excellent resistance to corrosion and excellent heat shock resistance, and thus is useful as a refractory material.

Abstract: The present invention provides a highly efficient, ceramic foam material for filtering molten metal which is characterized by improved strength reliability. The filter of the present invention is prepared by impregnating an organic foam material with an aqueous ceramic slurry containing ceramic fibers. In accordance with the present invention it has been found that it is possible to prepare a low cost, porous ceramic filtration medium having improved strength reliability.

Abstract: Process for the preparation of a foundry sand and the foundry sand composition which consists in mixing magnesium silicate and an arylsulphonic acid in aqueous medium as the binder.

Abstract: The invention refers to an unshaped refractory composition which can be used in the construction of glass furnace hearths and which comprises by weight:(a) 55 to 99% of particles of a fused cast refractory material, the fused cast refractory material including a vitreous phase and containing, as main constituents, ZrO.sub.2, Al.sub.2 O.sub.3, SiO.sub.2, and optionally Cr.sub.2 O.sub.3 ;(b) 0 to 5% of a hydraulic cement;(c) 1 to 15% of a filler consisting of very fine, substantially spherical particles of a metal oxide;(d) 0 to 25% of fine particles of a size less than 40 microns chosen from particles of ZrO.sub.2, Al.sub.2 O.sub.3, Cr.sub.2 O.sub.3, fused cast refractory products comprising by weight 75-85% ZrO.sub.2, 2-8% SiO.sub.2, 9-17% Al.sub.2 O.sub.3, 0.5-0.7% of other oxides, and mixtures thereof; and(e) 0.01 to 1% of a surface-active agent, the amount being with respect to the total weight of the constituents (a), (b), (c) and (d).

Abstract: The present invention relates to low-expansion ceramics essentially consisting of 1.5 to 20% by weight of magnesia (MgO), 8 to 68% by weight of alumina (Al.sub.2 O.sub.3), 24 to 80% by weight of titanium in terms of titanium oxide (TiO.sub.2), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe.sub.2 O.sub.3), that major component of crystalline phase thereof is a solid solution of magnesium oxide-aluminum oxide-titanium dioxide-iron oxide, and that the ceramics has a coefficient of thermal expansion of not more than 20.times.10.sup.-7 (1/.degree. C.) in a temperature range of 25.degree. C. to 800.degree. C. and a melting point of not lower than 1,500.degree. C., said coefficient of thermal expansion being maintained even after exposure 1,100.degree. C. for 1,000 hours, and a method of producing low-expansion ceramics comprising steps of preparing a batch of compounds so as to provide a chemical composition of 1.5 to 20% by weight of magnesia (MgO), 8 to 68% by weight of alumina (Al.sub.2 O.sub.

Abstract: A sintered ceramic body of high toughness, consisting of an isotropic ceramic matrix (e.g. Al.sub.2 O.sub.3) and at least one therein-dispersed phase (ZrO.sub.2, HzO.sub.2) of ceramic embedment material formed from a powder consisting of particles having an average diameter from 0.3 to 1.25 .mu.m, wherein the ceramic embedment material is present in different enantiotropic solid modifications at the firing temperature of the ceramic body and below the firing temperature, whose densities are substantially different, and the ceramic body is shot through with extremely fine microfractures in high density.

Abstract: A monolithic refractory composition including from about 63% to about 90% by weight high purity Al.sub.2 O.sub.3 ; from about 2% to 8% by weight crystalline silica having a particle size of -200 mesh; from about 2% to 6% by weight high purity Cr.sub.2 O.sub.3 ; from about 1% to 8% by weight high purity kaolin clay having a particle size of -10.mu. (micron); and from about 5% to 15% by weight phosphate binder. About 1-5% water may be substituted for Al.sub.2 O.sub.3. Preferably, the high purity Al.sub.2 O.sub.3 is a mixture of tabular alumina and calcined alumina and the phosphate binder is H.sub.3 PO.sub.4.

Abstract: The invention provides a novel class of sintered refractory and abrasive ies composed mainly of one or a combination of metal diborides such as titanium diboride TiB.sub.2, chromium diboride CrB.sub.2, tantalum diboride TaB.sub.2 and the like admixed with a minor amount of one or more kinds of metal borides exemplified by MnB, Mn.sub.3 B.sub.4, Mn.sub.2 B, Mn.sub.4 B, TiB, Ti.sub.2 B.sub.5, Ti.sub.2 B, W.sub.2 B.sub.5 and Mo.sub.2 B.sub.5. The sintered body can be prepared by conventional powder metallurgical processes such as hot pressing or sintering of a green body shaped in advance by molding in cold with the powder blend of the above described components. Further advantages are obtained by admixing the powder blend with small amounts of one or more of binder ingredients of relatively low melting points such as cobalt borides, iron borides, nickel borides and an alloy of nickel and phosphorus. So-called infusion process is also applicable for the preparation of the inventive sintered body.

Abstract: A ceramically bonded brick made from a batch consisting essentially of fused zirconia-mullite grain or fused zirconia-alumina grain, chromic oxide, and high alumina material.