Hot isostatic pressing of high performance electrical components

Claim 1

A method of forming a high density electrical contact comprising the steps: (A) mixing: (a) powders from class 1 metals selected from the group consisting of Ag, Cu, and mixtures thereof, with (b) powders from the class selected from the group consisting of CdO, W, WC, Co, Cr, Ni, C, and mixtures thereof, where the powder particles have particle sizes of up to approximately 100 microns diameter; (B) heating the powders in a reducing atmosphere at a temperature effective to provide an oxide clean surface on the powders, except CdO, and more homogeneous distribution of class 1 metals, (C) granulating the powder from step (B) to again provide powder having particle sizes of up to approximately 100 microns diameter; (D) uniaxially pressing the powders without heating, to provide a compact that is from 65% to 95% dense, and then (E) placing at least one compact in a pressure-transmitting, pressure-deformable container and surrounding each compact with fine particles of a separating material, which aids subsequent separation of the compact and the container, and then (F) evacuating air from the container, and then (G) sealing the compacts inside the container, and then (H) hot isostatically pressing the compacts through the pressure transmitting container, at a pressure of from 372 kg/cm 2 to 2,115 kg/cm 2 , and a temperature of from 0.5° C. to 100° C. below the melting point or decomposition point of the lower melting powder constituent, to provide simultaneous hot-pressing and densification of the compacts, and then (I) gradually cooling and releasing the pressure on the compacts so that the compacts cool under pressure, to provide a compact at least 98% dense, and then (J) separating the compacts from the container, where, in the process, there is no heating of the compacts before step (H).

Claim 2

A method of forming a high density electrical contact comprising the steps: (A) mixing: (a) powders from class 1 metals selected from the group consisting of Ag, Cu, and mixtures thereof, with (b) powders from the class selected from the group consisting of CdO, W, WC, Co, Cr, Ni, C, and mixtures thereof, where the powder particles have particle sizes of up to approximately 100 microns diameter; (B) heating the powders in a reducing atmosphere at a temperature effective to provide an oxide clean surface on the powders, except CdO, and more homogeneous distribution of class 1 metals, (C) granulating the powder from step (B) to again provide powder having particle sizes of up to approximately 100 microns diameter; (D) uniaxially pressing the powders without heating, to provide a compact that is from 65% to 95% dense, and then (E) placing at least one compact in a pressure-transmitting, pressure-deformable container and surrounding each compact with fine particles of a separating material, which aids subsequent separation of the compact and the container, and then (F) evacuating air from the container, and then (G) sealing the compacts inside the container, and then (H) hot isostatically pressing the compacts through the pressure transmitting container, at a pressure of from 372 kg/cm 2 to 2,115 kg/cm 2 , and a temperature of from 0.5° C. to 100° C. below the melting point or decomposition point of the lower melting powder constituent, to provide simultaneous hot-pressing and densification of the compacts, and then (I) gradually cooling and releasing the pressure on the compacts so that the compacts cool under pressure, to provide a compact at least 98% dense, and then (J) separating the compacts from the container, where, in the process, there is no heating of the compacts before step (H).