The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 18, 1992
Filed:
Nov. 23, 1990
Nicholas D Butler, Rugby, GB;
John Woodthrope, Rugby, GB;
Francisco C Fernandez, San Sebastian, ES;
Inigo I Zubillaga, San Sebastian, ES;
T & N Technology, Warwickshire, GB;
Abstract
It is known to obtain from a sinterable powder (e.g., of silicon nitride+metallic oxide sintering aid) a shaped article with at least 95% theoretical density, by the hot isostatic pressing of a preshaped body of the powder while that body is encapsulated in a gas-impermeable capsule which is plastic at the temperature of the hot gas by which the isostatic pressure is applied. Until now, a pressure of the order of 100 MPa has been treated as the practical minimum necessary for hot isostatic pressing. By the invention, a pressure less than 20 MPa is used, in conjunction with a degassing of the preshaped body, carried out prior to encapsulation, as in a vacuum whose pressure is no more than a few mm of mercury, and preferably less than 1 mm (approximately equal to 0.15 kPa).