Abstract: A method of making imprints on the walls of portions of a tube obtained by the continuous molding of a ceramics-based paste and the cutting up of the tube, wherein immediately after the tube portions have been molded and are still deformable, they are placed on means parallel with the axis of the tube portions for rotating them around their axes of revolution, means are applied to the rotary means for exerting a pressure on at least a portion of the tubes so that such portions are clamped between the rotary means and the pressure-exerting means, the pressure-exerting means or the rotary means are provided with at least one imprint-making tool, the or each tool having a main direction which does not coincide with the direction of the axes of revolution of the tube portions, and means are applied to create a second relative movement between the tube portion and the or each tool, so that there is substantially no sliding between the tube portion and the or each tool.

Abstract: The invention relates to a method of manufacturing supports for porous filters.Supports are placed in contact with a first slip coating liquid containing in suspension a mineral powder comprising agglomerates between 10 and 30 microns in diameter, the resulting deposited layer is dried by heating it to approximately 100.degree. C., the layer is brushed so as to remove particles of powder which have not penetrated inside the pores, the thus-treated supports are placed in contact with a second slip coating liquid containing in suspension a mineral powder having a particle size between 1 and 8 microns, and the products obtained are heat-treated at approximately 1500.degree. C.The resulting filters are used for separating isotopes.

Abstract: Method for manufacturing a bone prosthesis made of porous alumina. Calibrated alumina grains are subjected to firing at a temperature lower than their sintering temperature; they are disintegrated, then compressed into a pressed mass, then the latter is subjected to sintering.

Abstract: Final sintering of an alumina powder containing a small portion of magnesia, baryta, lanthana, yttria, or salts of magnesium, barium, lanthanum or yttrium, in a non-oxidizing carbon monoxide atmosphere at a temperature above 1700.degree. C produces a translucent alumina article.