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Title: Process for producing silicon nitride based articles of high fracture toughness and strength

Abstract

A process for producing a silicon nitride-based article of improved fracture toughness and strength. The process involves densifying to at least 98% of theoretical density a mixture including (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 .mu.m and a surface area of about 8-12 m.sup.2 /g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 .mu.m and a surface area of about 2-4 m.sup.2 /g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. Optionally, the mixture may be blended with a binder and injection molded to form a green body, which then may be densified by, for example, hot isostatic pressing.

Inventors:
 [1];  [2];  [2]
  1. Marlboro, MA
  2. Acton, MA
Issue Date:
Research Org.:
LOCKHEED MARTIN ENRGY SYST INC
OSTI Identifier:
867976
Patent Number(s):
5047186
Assignee:
GTE Laboratories Incorporated (Waltham, MA)
DOE Contract Number:  
AC05-84OR21400
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
process; producing; silicon; nitride; based; articles; fracture; toughness; strength; nitride-based; article; improved; involves; densifying; 98; theoretical; density; mixture; including; bimodal; powder; blend; consisting; essentially; 10-30; weight; average; particle; size; surface; 8-12; 70-90; 4-0; 2-4; 10-50; percent; volume; densified; refractory; whiskers; fibers; aspect; ratio; 3-150; equivalent; diameter; selected; produce; grains; effective; amount; suitable; oxide; densification; optionally; blended; binder; injection; molded; form; green; example; hot; isostatic; pressing; theoretical density; nitride powder; effective amount; process involves; aspect ratio; fracture toughness; silicon nitride; consisting essentially; particle size; hot isostatic; isostatic pressing; producing silicon; average particle; mixture including; diameter ratio; improved fracture; silicon nitride-; silicon nitride-based; nitride-based article; injection molded; nitride base; /264/501/

Citation Formats

Huckabee, Marvin, Buljan, Sergej-Tomislav, and Neil, Jeffrey T. Process for producing silicon nitride based articles of high fracture toughness and strength. United States: N. p., 1991. Web.
Huckabee, Marvin, Buljan, Sergej-Tomislav, & Neil, Jeffrey T. Process for producing silicon nitride based articles of high fracture toughness and strength. United States.
Huckabee, Marvin, Buljan, Sergej-Tomislav, and Neil, Jeffrey T. Tue . "Process for producing silicon nitride based articles of high fracture toughness and strength". United States. https://www.osti.gov/servlets/purl/867976.
@article{osti_867976,
title = {Process for producing silicon nitride based articles of high fracture toughness and strength},
author = {Huckabee, Marvin and Buljan, Sergej-Tomislav and Neil, Jeffrey T},
abstractNote = {A process for producing a silicon nitride-based article of improved fracture toughness and strength. The process involves densifying to at least 98% of theoretical density a mixture including (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 .mu.m and a surface area of about 8-12 m.sup.2 /g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 .mu.m and a surface area of about 2-4 m.sup.2 /g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. Optionally, the mixture may be blended with a binder and injection molded to form a green body, which then may be densified by, for example, hot isostatic pressing.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1991},
month = {1}
}

Patent:

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