A process for recovery of all or some abrasive elements contained in an abrasive material in which the abrasive elements are dispersed in a resin with at least one phenolic hydroxyl group, the process including steps of: a) bringing the abrasive material into contact with an aqueous nitric solution (S.sub.1), whereby an aqueous nitric solution (S.sub.2) is obtained containing abrasive elements and residue derived from degradation of the resin; then (b) separating the abrasive elements from the aqueous nitric solution (S.sub.2) obtained after step (a). The use of abrasive elements thus recovered particularly to prepare agglomerated abrasives or coated abrasives.

A composition is provided for forming a sodium-ion conducting electrolyte structure, comprising particles of a sodium-ion-conducting ceramic, combined with particles of at least one transition metal oxide, such as copper, titanium and niobium oxides, or iron oxide, or precursors for these oxides, so the metal oxides make up no more than 5% by weight of the weight of the particles. The sodium-ion-conducting ceramic may be of the types referred to as Nasicon, or ?-alumina. The metal oxides may constitute no more than 2% of the weight of the particles. The metal oxides act as a sintering aid, making it possible to achieve densification at a reduced sintering temperature, while having no significant detrimental effect on the electrical properties of the sintered ceramic. The invention also encompasses an electrode structure made by sintering this composition.

The present invention relates to a honeycomb structured body including a honeycomb fired body in which multiple through-holes are arranged longitudinally in parallel with one another with a partition wall therebetween, wherein the honeycomb fired body is an extrudate containing ceria-zirconia composite oxide particles and alumina particles, the ceria-zirconia composite oxide particles have an average particle size of 1 to 50 m, and the ceria-zirconia composite oxide particles include a cracked particle.

The present invention relates to a honeycomb structured body including a honeycomb fired body in which multiple through-holes are arranged longitudinally in parallel with one another with a partition wall therebetween, wherein the honeycomb fired body is an extrudate containing ceria-zirconia composite oxide particles, -alumina particles, -alumina, and -alumina fibers, and the honeycomb fired body has a porosity of 55 to 70%.

An elongate shaped abrasive particle comprises an elongate shaped ceramic body having opposed first and second ends joined to each other by at least two longitudinal sidewalls. At least one of the at least two longitudinal sidewalls is concave along its length. At least one of the first and second ends is a fractured surface. Methods of making elongate shaped abrasive particles and abrasive articles including them are also disclosed.

In one aspect, sintered ceramic bodies are described herein which, in some embodiments, demonstrate improved resistance to wear and enhanced cutting lifetimes. For example, a sintered ceramic body comprises tungsten carbide (WC) in an amount of 40-95 weight percent, alumina in an amount of 5-30 weight percent and ditungsten carbide (W.sub.2C) in an amount of at least 1 weight percent.

A method of making a carbon-carbon composite part may comprise fabricating a fibrous preform comprising a fiber volume ratio of 25% or greater, heat treating the fibrous preform at a first temperature, infiltrating the fibrous preform with a first ceramic suspension, densifying the fibrous preform by chemical vapor infiltration (CVI) to form a densified fibrous preform, and heat treating the densified fibrous preform at a second temperature of 1600 C. or greater.

Two ceramic or sapphire pieces are welded together using a plasma torch that includes a cylindrical vessel having first and second ends, a tangential inlet connected to or proximate to the first end, a tangential outlet connected to or proximate to the second end, an electrode housing connected to the first end of the cylindrical vessel such that a first electrode is aligned with a longitudinal axis of the cylindrical vessel, and extends into the cylindrical vessel. A hollow electrode nozzle is connected to the second end of the cylindrical vessel such that the center line of the hollow electrode nozzle is aligned with the longitudinal axis of the cylindrical vessel. A second electrode is positioned proximate to the hollow electrode nozzle. The two ceramic or sapphire pieces are placed between the second electrode and the hollow electrode, and are welded together with the plasma exiting from the hollow electrode.

A method comprises reacting an aluminum feedstock with an acid in the presence of water to provide an aluminum salt solution comprising an aluminum salt in water, wherein the aluminum salt comprises a reaction product of the acid and aluminum, and spray roasting the aluminum salt solution at a temperature of at least about 450 C. to provide an aluminum oxide powder, wherein the spray roasting is performed in a furnace lined with a refractory comprising alumina that is at least about 99.2% purity alumina, and wherein the aluminum oxide powder is 99.2% pure aluminum oxide or greater.

In one aspect, sintered ceramic bodies are described herein which, in some embodiments, demonstrate improved resistance to wear and enhanced cutting lifetimes. For example, a sintered ceramic body comprises tungsten carbide (WC) in an amount of 40-95 weight percent, alumina in an amount of 5-30 weight percent and ditungsten carbide (W.sub.2C) in an amount of at least 1 weight percent.