NIST Structural Ceramics Database (SCD) Database

NIST Standard Reference Database 30

Last Update to Data Content: 2002

DOI: http://dx.doi.org/10.18434/T4F30D


SCD Citation Number: Z00004

Bibliographic Information

Reference:
"Fracture and Intermediate Temperature Instability in Yttria-Doped Hot-Pressed Silicon Nitrides," R.K. Govila, American Ceramic Society Bulletin, Vol. 65 [9], pp. 1287-1292 (1986), published by American Ceramic Society.
Language: English

General Materials Processing Notes

Billets were 150 mm x 150 mm x 25 mm. WC balls used in ball-milling led to WSi2 contamination. Specimens were machined to 32 mm x 6 mm x 3 mm with tensile faces perpendicular to the hot-pressing direction; faces were ground lengthwise using 320 grit diamond wheels; and edges were chamfered lengthwise. Sintering aids were 7-8% Y2O3 plus 1-2% Al2O3.

Measurement Methods

Four-point bend test
The measurement was made by four-point bend method using a self-aligning fixture, 1/4-point loading, Instron test machine (Model 1125), and crosshead speed = 0.5 mm/min. Specimens were heated at test temperature for 30 min to 45 min before testing in air.

Index of Materials and Properties

SCD Citation Number: Z00004
Material Number 1: Si3N4·x Y2O3·y Al2O3

Material Specification and Properties for Si3N4·x Y2O3·y Al2O3

Material number 1 of 1
in SCD Citation Number: Z00004
Chemical Class: Nitride
Chemical Family: Si-N:Al2O3,Y2O3
Formula: Si3N4·x Y2O3·y Al2O3
Informal Name: silicon nitride
Structure Type: Polycrystalline
Manufacturer: In-House
Production Form: Disk
Process: Hot Pressing

Si3N4·x Y2O3·y Al2O3

Material number 1 of 1
in SCD Citation Number: Z00004
Elemental Composition
Amount of
Element
( formula units )
Element
 
( no unit )
3 Si
4 N

Measurement Method: Reported Formula
Evaluation Status: Unevaluated

Si3N4·x Y2O3·y Al2O3

Material number 1 of 1
in SCD Citation Number: Z00004
Sintering Aids
Sintering Aid
Mass Fraction
( % )
Sintering Aid
 
( no unit )
7.5 ± 0.5 Y2O3
1.5 ± 0.5 Al2O3
Measurement Method: Reported Formula
Evaluation Status: Unevaluated

Si3N4·x Y2O3·y Al2O3

Material number 1 of 1
in SCD Citation Number: Z00004
Impurities
Mass Fraction
of Impurity
( % )
Impurity
 
( no unit )
0.50 Al
0.05 Ca
0.75 Fe
0.10 Mg
3.00 W
Measurement Method: Reported Formula
Evaluation Status: Unevaluated

Si3N4·x Y2O3·y Al2O3

Material number 1 of 1
in SCD Citation Number: Z00004
Flexural Strength
Temperature
 
( °C )
Flexural
Strength
( MPa )
20 851 ± 85
400 807 ± 65
500 799 ± 74
600 719 ± 143
700 636 ± 157
800 653 ± 140
1000 656 ± 104

Measurement Method: Four-point bend test
Evaluation Status: Evaluated by acceptance criteria
Cautions:
The authors suggested that failure strength is independent of temperature up to 500 °C.

Si3N4·x Y2O3·y Al2O3

Material number 1 of 1
in SCD Citation Number: Z00004
Weibull Modulus
Temperature
 
( °C )
Weibull
Modulus
( no unit )
20 12
400 15
500 13
600 5.8
700 4.6
800 5.4
1000 7.4

Measurement Method: Four-point bend test
Evaluation Status: Evaluated by acceptance criteria

Si3N4·x Y2O3·y Al2O3

Material number 1 of 1
in SCD Citation Number: Z00004
Weibull Strength
Temperature
 
( °C )
Weibull
Strength
( MPa )
20 886
400 834
500 828
600 770
700 690
800 703
1000 692

Measurement Method: Four-point bend test Evaluation Status: Evaluated by acceptance criteria