Abstract: A high density, shock resistant ceramic comprising from 1 to about 4 mols of a a dense spinel ceramic matrix having dispersed therein, 1.5 to 1, respectively, of a metal oxide derived from a decomposable salt of said metal and having a thermal expansion characteristic different from said dense spinel ceramic matrix and at the decomposition temperature a volume less than that exhibited by its salt form and a process for preparing same.

Abstract: A composite ceramic material having improved properties is disclosed as well as several methods for preparing the same. The composite powder is substantially comprised of zirconia and spinel phases, produced by precipitation and calcination of the precipitate of the oxide forming precursor salts. A preferred method for introducing the zirconium is as a soluble and/or decomposable salt during precipitation of the spinel forming hydroxyl or halo hydroxyl spinel forming salts. The zirconium salt decomposes to zirconia during calcining and/or sintering of the powder resulting from the precipitation. A preferred composite is that obtained from magnesium and aluminum salts, resulting in a MgAl.sub.2 O.sub.4 spinel and intimately admixed ZrO.sub.2 which contains a stabilizing agent.

Abstract: A high density, shock resistant ceramic comprising from 1 to about 4 mols of a dense spinel ceramic matrix having dispersed therein, 1.5 to 1, respectively, of a metal oxide derived from a decomposable salt of said metal and having a thermal expansion characteristic different from said dense spinel ceramic matrix and at the decomposition temperature a volume less than that exhibited by its salt form and a process for preparing same.

Abstract: There is disclosed a coating compositions which can be produced from (1) a reactive MgAl.sub.2 O.sub.4 spinel (2) aluminum acid phosphate moieties and phosphoric acid, (3) water, (4) optionally, non-reactive fillers, colorants and (5), also optionally, handling agents.

Abstract: There is disclosed a unique substantially non-reactive refractory material suitable for use as a material of construction for various component parts of an electrolytic light metal, particularly magnesium, production cell. The non-reactive refractory material is comprised of a magnesium aluminum spinel. When used in block form the blocks may be joined together by use of a phosphate-spinel mortar.

Abstract: A new and useful family of compounds is prepared by fluoride substitution into a cobalt oxide spinel, the new compounds conforming substantially to the empirical formula Co.sub.3 O.sub.x F.sub.y or M.sub.1 'M.sub.2 "--M.sub.i.sup.n Co.sub.(3-.SIGMA.) O.sub.x F.sub.y, where x+2y.congruent.4, where y is an amount such that F.ltoreq.2 wt. % of the compound, and where M.sub.1, M.sub.2, and M.sub.i each represent metal values other than Co. Thus the cobalt oxide spinel may be a single-metal spinel, a bimetal spinel, a trimetal spinel, or a polymetal spinel.

Abstract: A composition comprised ofI. 60 to 90% wt. of(a) from 70 to 95 weight percent of at least one of(i) one or more MgAl.sub.2 O.sub.4 spinels heated at a temperature of about 600.degree. C. to about 1700.degree. C. and having less than 20% by weight of segregated phases of Al.sub.2 O.sub.3 or MgO;(ii) MgAl(OH).sub.5-ny X.sub.y.sup.n where y.ltoreq.1; x=OH.sup.-, halogen, SO.sub.4.sup.=, NO.sub.3.sup.- carboxylate, halogenated carboxylate, H.sub.2 PO.sub.4.sup.-, HPO.sub.4.sup.=, HCO.sub.3.sup.-, and the like which is prepared by coprecipitating a Mg and Al salt under controlled pH and Mg/Al ratios and which may also include segregated phases of AlO(OH), Mg(OH).sub.2 and/or Al(OH).sub.3 following pH adjustment;(iii) intermediates of (1) and (2) prepared by partial calcination of (2) at temperatures .gtoreq.300.degree. C. but .ltoreq.600.degree. C.

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: A method for preparing spinel (MgAl.sub.2 O.sub.4) surfaces on alumina or alumino silicate articles or shapes by exposure of the article or shape to molten or vaporous magnesium or magnesium alloy for from two to ten hours under nonpyrophoric conditions.