Abstract: Laminated extruded thermal shock resistant composite articles formed from sinterable particulate or powdered materials such as ceramics are disclosed. The laminated extruded composite articles have multiple discrete layers of at least a first and second sintered material, where the first and second sintered materials are different and are selected from high strength sintered particulate or powdered materials and where the layers of each of said first and second sintered materials are substantially uniformly distributed throughout the article.

Abstract: An improved method for encasing objects in metal is disclosed as are the novel encased objects so prepared. An object is wrapped with a sheet comprising sinterable particulate or powdered metal and an organic binder, and is the fired to volatilize the binder and to sinter the particulate metal into a unitary metal structure. In the preferred embodiment of this invention, the object to be encased is a green sinterable particulate object which undergoes sintering simultaneously with the particulate metal casing during the firing step.

Abstract: A method is provided of preparing high-purity mixtures of zirconia and another metal oxide substantially free of sodium oxide impurity. Trioxydizirconium ion and a salt of another metal in an aqueous solution are added to a highly basic solution, resulting in the homogeneous precipitation of the combined hydroxides or hydrous oxides. The precipitate is recovered, washed with the water and then with an organic solvent, and then dried, most preferably employing an azeotropic distillation procedure. The resulting material is then calcined to provide a mixture of zirconia with the other metal oxide. In a preferred embodiment, the zirconia mixtures are in the form of fine powders which can be sintered to form a product having greater than 99% of its theoretical density.