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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 is disclosed. 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:
; ;
Publication Date:
OSTI Identifier:
7174515
Patent Number(s):
US 5047186; A
Application Number:
PPN: US 7-458122
Assignee:
GTE Laboratories Incorporated, Waltham, MA (United States) PTO; EDB-94-110284
DOE Contract Number:  
AC05-84OR21400
Resource Type:
Patent
Resource Relation:
Patent File Date: 28 Dec 1989
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COMPOSITE MATERIALS; FABRICATION; SILICON NITRIDES; BINDERS; COMPACTING; FIBERS; FRACTURE PROPERTIES; HOT PRESSING; MOLDING; WHISKERS; CRYSTALS; MATERIALS; MATERIALS WORKING; MECHANICAL PROPERTIES; MONOCRYSTALS; NITRIDES; NITROGEN COMPOUNDS; PNICTIDES; PRESSING; SILICON COMPOUNDS; 360601* - Other Materials- Preparation & Manufacture

Citation Formats

Huckabee, M., Buljan, S.T., and Neil, J.T. Process for producing silicon nitride based articles of high fracture toughness and strength. United States: N. p., 1991. Web.
Huckabee, M., Buljan, S.T., & Neil, J.T. Process for producing silicon nitride based articles of high fracture toughness and strength. United States.
Huckabee, M., Buljan, S.T., and Neil, J.T. Tue . "Process for producing silicon nitride based articles of high fracture toughness and strength". United States.
@article{osti_7174515,
title = {Process for producing silicon nitride based articles of high fracture toughness and strength},
author = {Huckabee, M. and Buljan, S.T. and Neil, J.T.},
abstractNote = {A process for producing a silicon nitride-based article of improved fracture toughness and strength is disclosed. 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 = {9}
}