A process for preparing an electride compound, comprising (i) providing a precursor compound comprising an oxidic compound of the garnet group; (ii) heating the precursor provided in (i) under plasma forming conditions in a gas atmosphere to a temperature of the precursor above the Httig temperature of the precursor, obtaining the electride compound.

A method of preparation of semiconductor material. The method includes: adding an organic substance containing a benzene ring and dodecacalcium hepta-aluminate (12CaO.7Al.sub.2O.sub.3 or C12A7) to a test tube, and sealing the test tube; heating the test tube to a temperature of 200-300 C., and holding the temperature for 1 to 3 hours; and continuously heating the test tube to a temperature of 900-1300 C., and holding the temperature for 10-120 hours.

Disclosed is a method for manufacturing calcium aluminates in an industrial furnace, according to which, continuously, into a tank made of refractory material containing a molten pool that is constantly heated, fine particles are introduced of a raw material source of alumina and/or of aluminium and of a raw material source of calcium oxide and/or of calcium having a median diameter d50 less than or equal to 6,000 m in order to melt the fine particles of raw material, and, continuously, at the outlet of the tank a mass of liquid calcium aluminates is recovered.

An object of the present invention is to provide a method for producing conductive mayenite, with which a reaction is completed in a short time, an operation can be simplified, the reaction is easily controlled, and the cost of energy can be reduced. The present invention is a method for producing conductive mayenite, characterized by mixing a mayenite type compound with a carbon component, placing the resulting mixture in an airtight container, and irradiating the mixture with a microwave in an inert gas atmosphere or in a vacuum atmosphere to heat the mixture.

In a first step of a method for producing a transparent AlN sintered body, first, a formed body is prepared by forming a mixture obtained by mixing a sintering aid with an AlN raw-material powder containing a plate-like AlN powder whose plate surface is a c-plane and which has an aspect ratio of 3 or more. At this time, the mixture is formed such that the plate surface of the plate-like AlN powder is disposed along a surface of the formed body. In a second step, an oriented AlN sintered body is obtained by subjecting the formed body to hot-press sintering in a non-oxidizing atmosphere while applying a pressure to the surface of the formed body. In a third step, a transparent AlN sintered body is obtained by sintering the oriented AlN sintered body at normal pressure in a non-oxidizing atmosphere to remove a component derived from the sintering aid.

Disclosed is a method for manufacturing crystals of aluminates of one or more element(s) other than aluminium, referred to as A. The method includes: placing starting reagents, including at least one aluminium element source and a source of the element(s) A that has a degree of oxidation of between 1 and 6, in suspension in a liquid medium, forming a suspension referred to as the starting suspension; milling the starting suspension at 50 C., in a three-dimensional liquid medium ball mill for 5 minutes; recovering, at the outlet of the three-dimensional ball mill, a suspension referred to as the end suspension including the starting reagents in activated form or crystals of aluminate of the element(s) A generally in hydrated form; if required, calcination of the end suspension when it includes the starting reagents in activated form, to obtain generally non-hydrated crystals of aluminate of the element(s) A.

An oxide ion-conducting solid electrolyte is provided. The oxide ion-conducting solid electrolyte contains a mayenite-type compound having a representative composition represented by Ca.sub.12Al.sub.14O.sub.33, and at least one metal element M selected from lanthanum (La) and yttrium (Y), wherein the metal element M is contained in a range of from 0.4 mol % through 5.3 mol % in terms of an oxide relative to the whole of the oxide ion-conducting solid electrolyte.

The invention relates to a composite oxide comprising CaO stabilised by Ca.sub.3AI.sub.2O.sub.6 (C3A), wherein the composite is in the form of particles. The mixed oxide composite is useful as a catalyst in the transesterification of triglycerides, e.g. in the production of biodiesel. Calcium leaching is more hindered in CaOCa.sub.3AI.sub.2O.sub.6 (2Ca/AI) than in CaO-AI.sub.2O.sub.3.

If a conductive mayenite compound having a large specific surface area is obtained, the usefulness thereof in respective applications is remarkably increased. A conductive mayenite compound powder having a conduction electron density of 10.sup.15 cm.sup.?3 or more and a specific surface area of 5 m.sup.2g.sup.?1 or more is produced by: the following steps: (1) forming a precursor powder by subjecting a mixture of a starting material powder and water to a hydrothermal treatment; (2) forming a mayenite compound powder by heating and dehydrating the precursor powder; (3) forming an activated mayenite compound powder by heating the compound powder in an inert gas atmosphere or in a vacuum; and (4) injecting electrons into the mayenite compound through a reduction treatment by mixing the activated mayenite compound powder with a reducing agent.

The present invention generally relates to the use of pre-formed bodies of Chemically Bonded Ceramics (CBCs) biomaterial for implantation purposes wherein the bodies are prepared ex vivo allowing process parameters to be optimized for desired long term properties of the resulting CBC biomaterial. More particularly, the pre-formed CBC material bodies of the present invention are sintered. The pre-formed body of CBC material is machined to the desired geometry and then implanted using a CBC cementation paste for fixation of the body to tissue. The invention also relates to a method of preparing pre-formed bodies of CBC biomaterial for implantation purposes, methods of preparing an implant thereof having desired geometry, and a method of implantation of the implant, as well as a kit for use in the method of implantation.