Patent GB-989255-A (GB)
Title: Compacting of particulate and/or fibrous materials
IPC: B01J2/22
Filed: 1962-01-22
Abstract: A particulate and/or fibrous material is encased in a jacket made from a non-elastomeric material having a higher compressibility than the material of the final product and which undergoes an abrupt densification at a predetermined pressure, and a high hydrostatic pressure at least as great as the predetermined pressure is applied to the jacket thus subjecting the particulate and/or fibrous material to a materially higher pressure to form a compact product mass of materially increased density. The jacket, which may be of cerium, caesium, bismuth or low melting bismuth-containing alloys, is then removed, e.g. by melting.  The particulate of fibrous material may be subjected to a preliminary compressing and shaping operation, for instance with a die and a binder, such as copper for tungsten fibres or cobalt for carbides may be admixed prior to the preliminary shaping operation.  The particulate material may be a powdered metal or non-metal, a metal or non-metal in the form of fibres or whiskers, or a powdered crystalline metal.  In the latter case application of high hydrostatic produces permanent changes in the properties of the material.  Examples of powdered and/or fibrous non-metals include carbides, oxides, chalcogenides of lanthanons, silicides, borides and nitrides.  Ceramic fibres, for instance sapphire fibres, dispersed in a cobalt-chromium alloy may also be used.ALSO:A particulate and/or fibrous material is encased in a jacket made from a non-elastomeric material having a higher compressibility than the material of the final product and which undergoes an abrupt densification at a predetermined pressure, and a high hydrostatic pressure at least as great as the predetermined pressure is applied to the jacket thus subjecting the particulate and/or fibrous material to a materially higher pressure to form a compact product mass of materially increased density.  The jacket which may be of cerium, caesium, bismuth or low melting bismuth-containing alloys is then removed, e.g. by melting.  The particulate or fibrous material may be subjected to a preliminary compressing and shaping operation, for instance with a die and a binder, such as copper for tungsten fibres or cobalt for carbides such as TiC may be admixed prior to the preliminary shaping operation.  The particulate material may be a powdered metal or non-metal, a metal or non-metal in the form of fibres or whiskers, or a powdered crystalline metal.  In the latter case application of high hydrostatic produces permanent changes in the properties of the material.  Metals include the ferrous metals, high temperature nickel and chromium containing alloys, a cobalt-chromium -nickel-molybdenum alloy and bearing metals, for example bronzes and graphite-containing bronzes. Examples of powdered and/or fibrous non-metals include carbides, oxides, chalcogenide of lanthanous, silicides, borides and nitrides.  Metals in the form of whiskers, e.g. platinum whiskers dispersed in copper may also be compacted.  Ceramic fibres, e.g. sapphire fibres dispersed in a cobalt-chromium alloy may also be used.