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

Patent · Tue Sep 10 00:00:00 EDT 1991

OSTI ID:7174515

Huckabee, M; Buljan, S T; Neil, J T

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.

• DOE Contract Number: AC05-84OR21400
• Assignee: GTE Laboratories Incorporated, Waltham, MA (United States)
• Patent Number(s): US 5047186; A
• Application Number: PPN: US 7-458122
• OSTI ID: 7174515
• Resource Relation: Patent File Date: 28 Dec 1989
• Country of Publication: United States
• Language: English

Related Subjects

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