Power mixture and green body for producing silicon nitride base & articles of high fracture toughness and strength

Patent · Tue Jan 01 00:00:00 EST 1991

OSTI ID:867991

Huckabee, Marvin L ^[1]; Buljan, Sergej-Tomislav ^[2]; Neil, Jeffrey T ^[2]

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1. Marlboro, MA
2. Acton, MA

A powder mixture and a green body for producing a silicon nitride-based article of improved fracture toughness and strength. The powder mixture includes 9a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon mitride powder of an average particle size of about 0.2 .mu.m and a surface area of about 8-12m.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 articel 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. The green body is formed from the powder mixture, an effective amount of a suitable oxide densification aid, and an effective amount of a suitable organic binder.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• DOE Contract Number: AC05-84OR21400
• Assignee: GTE Laboratories Incorporated (Waltham, MA)
• Patent Number(s): US 5049530
• OSTI ID: 867991
• Country of Publication: United States
• Language: English

Related Subjects

power
mixture
green
producing
silicon
nitride
base
articles
fracture
toughness
strength
powder
nitride-based
article
improved
9a
bimodal
blend
consisting
essentially
10-30
weight
mitride
average
particle
size
surface
8-12m
70-90
4-0
2-4
10-50
percent
volume
based
densified
refractory
whiskers
fibers
aspect
ratio
3-150
equivalent
diameter
selected
produce
articel
grains
effective
amount
suitable
oxide
densification
formed
organic
binder
organic binder
nitride powder
effective amount
aspect ratio
fracture toughness
silicon nitride
consisting essentially
particle size
producing silicon
average particle
powder mixture
diameter ratio
improved fracture
silicon nitride-
silicon nitride-based
nitride-based article
nitride base
/501/