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: Z00042

Bibliographic Information

Reference:
"Investigation of Selected Si3N4 and SiC Ceramics," N.L. Hecht, D.E. McCullum, and G.A. Graves, Ceramic Materials and Components for Engines, pp. 806-816 (1988), edited by V.J. Tennery, published by American Ceramic Society.
Language: English
Notes: Third International Symposium, Las Vegas, NV, Nov. 27-30

General Materials Processing Notes

Material #1: "Sohio - Hexoloy α-SiC, Cold formed (injection molded or isostatic pressing) and pressureless sintered α-SiC with additions of B and Al" Material #2: "GTE - PY6, Injection molded and hipped β Si3N4 with additions of Y2O3" Material #3: "Norton/TRW - NT154, Sintered and HIP'ed Si3N4"

Measurement Methods

Four-point bend test
Rectangular test bars, 51 mm x 6.4 mm x 3.2 mm, were used. The tensile surfaces were ground, and the long edges of the tensile surface were chamfered. The Instron Universal Testing Machine, Model 1123 was used. Measurements at 1300 °C and 1450 °C used an ATS #3320 high temperature furnace. For room temperature tests, the bend fixture was made of steel. For tests at 1300 °C and 1450 °C, the bend fixture was made of SiC. The four-point bend fixture had an outer span of 3.81 cm and an inner span of 1.90 cm. A Weibull analysis was performed with the Weibull modulus being determined using a maximum likelihood estimate.
Transient impulse
Three specimens were measured, one at a time, in a Grindo-Sonic, Model MR3ST, Transient Impulse/Elastic modulus apparatus.
Dilatometry
Measurements were made on four specimens, from 25 °C to 1450 °C, using a Theta Industries Dilatronic II, Model 6024, apparatus.
Vickers indentation
Five representative specimens were used for each material in a Vickers microindentation hardness tester. No additional measurement details were noted.

Index of Materials and Properties (Click on a selected Material Number to expand material properties menu)

SCD Citation Number: Z00042

Material Specification and Properties for SiC

Material number 1 of 3
in SCD Citation Number: Z00042
Chemical Class: Carbide
Chemical Family: Si-C
Formula: SiC
Informal Name: silicon carbide
Structure Type: Polycrystalline
Manufacturer: Sohio Engineered Materials Co.
Commercial Name: Hexoloy SA
Process: Sintering

SiC

Material number 1 of 3
in SCD Citation Number: Z00042
Elemental Composition
Amount of
Element
( formula units )
Element
 
( no unit )
1 Si
1 C
Measurement Method: Reported Formula
Evaluation Status: Unevaluated

SiC

Material number 1 of 3
in SCD Citation Number: Z00042
Sintering Aids
Sintering Aid
 
( no unit )
B
Al
Measurement Method: Reported Formula
Evaluation Status: Unevaluated

SiC

Material number 1 of 3
in SCD Citation Number: Z00042
Density (mass)
Temperature
 
( °C )
Density
 
( g cm-3 )
25 3.17
Measurement Method: Unknown
Evaluation Status: Unevaluated

SiC

Material number 1 of 3
in SCD Citation Number: Z00042
Elastic Modulus
Temperature
 
( °C )
Elastic
Modulus
( GPa )
25 427
Measurement Method: Transient impulse
Evaluation Status: Evaluated by acceptance criteria

SiC

Material number 1 of 3
in SCD Citation Number: Z00042
Flexural Strength
Temperature
 
( °C )
Crosshead
Speed
( cm/s )
Flexural
Strength
( MPa )
25 0.0064 331
1300 0.0064 494
1450 0.0064 500
25 0.004 402
1000 0.004 416
1200 0.004 435
1400 0.004 436
1000 0.00004 412
1200 0.00004 441
1300 0.00004 500
1400 0.00004 390
1450 0.00004 455
Measurement Method: Four-point bend test
Evaluation Status: Evaluated by acceptance criteria
Cautions:
Standard deviations ranged from 6 MPa to 90 MPa and tended to be about 50 MPa. Failures occurred at tensile surface and edge flaws.

SiC

Material number 1 of 3
in SCD Citation Number: Z00042
Fracture Toughness
Temperature
 
( °C )
Fracture
Toughness
( MPa m1/2 )
25 2.6
Measurement Method: Vickers indentation
Evaluation Status: Unevaluated
Cautions:
"The fracture toughness values measured by the microindent method are found to be considerably higher (greater than 20%) than those measured by the controlled flaw method."

SiC

Material number 1 of 3
Hardness
Temperature
 
( °C )
Hardness
 
( GPa )
25 25.1
Measurement Method: Vickers indentation
Evaluation Status: Unevaluated

SiC

Material number 1 of 3
in SCD Citation Number: Z00042
Thermal Expansion
Temperature
 
( °C )
Thermal
Expansion
( 10-6 K-1 )
25-1450 5
Measurement Method: Dilatometry
Evaluation Status: Evaluated by acceptance criteria

SiC

Material number 1 of 3
Weibull Modulus
Temperature
 
( °C )
Crosshead
Speed
( cm/s )
Weibull
Modulus
( no unit )
25 0.0064 9
1300 0.0064 8
1450 0.0064 10
25 0.004 9
1000 0.004 18
1200 0.004 9
1400 0.004 11
1000 0.00004 12
1200 0.00004 10
1300 0.00004 8
1400 0.00004 15
1450 0.00004 9
Measurement Method: Four-point bend test
Evaluation Status: Evaluated by acceptance criteria

Material Specification and Properties for Si3N4·xY2O3

Material number 2 of 3
in SCD Citation Number: Z00042
Chemical Class: Nitride
Chemical Family: Si-N:Y2O3
Formula: Si3N4·xY2O3
Informal Name: silicon nitride
Structure Type: Polycrystalline
Manufacturer: GTE
Commercial Name: PY6
Process:

Si3N4·xY2O3

Material number 2 of 3
in SCD Citation Number: Z00042
Elemental Composition
Amount of
Element
( formula units )
Element
 
( no unit )
3 Si
4 N
Measurement Method: Reported Formula
Evaluation Status: Unevaluated

Si3N4·xY2O3

Material number 2 of 3
in SCD Citation Number: Z00042
Sintering Aids
Sintering Aid
 
( no unit )
Y2O3
Measurement Method: Reported Formula
Evaluation Status: Unevaluated

Si3N4·xY2O3

Material number 2 of 3
in SCD Citation Number: Z00042
Density (mass)
Temperature
 
( °C )
Density
 
( g cm-3 )
25 3.24
Measurement Method: Unknown
Evaluation Status: Unevaluated

Si3N4·xY2O3

Material number 2 of 3
in SCD Citation Number: Z00042
Elastic Modulus
Temperature
 
( °C )
Elastic
Modulus
( GPa )
25 293
Measurement Method: Transient impulse
Evaluation Status: Evaluated by acceptance criteria

Si3N4·xY2O3

Material number 2 of 3
in SCD Citation Number: Z00042
Flexural Strength
Temperature
 
( °C )
Crosshead
Speed
( cm/s )
Flexural
Strength
( MPa )
25 0.0064 641
1450 0.0064 393
1450 0.00004 241
Measurement Method: Four-point bend test
Evaluation Status: Evaluated by acceptance criteria
Cautions:
Standard deviations were approximately 69 MPa. Specimens failed at tensile surface, edge, and subsurface flaws.

Si3N4·xY2O3

Material number 2 of 3
in SCD Citation Number: Z00042
Fracture Toughness
Temperature
 
( °C )
Fracture
Toughness
( MPa m1/2 )
25 6.1
Measurement Method: Vickers indentation
Evaluation Status: Unevaluated

Si3N4·xY2O3

Material number 2 of 3
in SCD Citation Number: Z00042
Hardness
Temperature
 
( °C )
Hardness
 
( GPa )
25 14.3
Measurement Method: Vickers indentation
Evaluation Status: Unevaluated

Si3N4·xY2O3

Material number 2 of 3
Thermal Expansion
Temperature
 
( °C )
Thermal
Expansion
( 10-6 K-1 )
25-1450 3.4
Measurement Method: Dilatometry
Evaluation Status: Evaluated by acceptance criteria

Si3N4·xY2O3

Material number 2 of 3
in SCD Citation Number: Z00042
Weibull Modulus
Temperature
 
( °C )
Crosshead
Speed
( cm/s )
Weibull
Modulus
( no unit )
25 0.0064 11
1450 0.0064 8
1450 0.00004 7
Measurement Method: Four-point bend test
Evaluation Status: Evaluated by acceptance criteria

Material Specification and Properties for Si3N4

Material number 3 of 3
in SCD Citation Number: Z00042
Chemical Class: Nitride
Chemical Family: Si-N
Formula: Si3N4
Informal Name: silicon nitride
Structure Type: Polycrystalline
Manufacturer: Norton/TRW
Commercial Name: NT-154
Process: Hot Isostatic Pressing

Si3N4

Material number 3 of 3
in SCD Citation Number: Z00042
Elemental Composition
Amount of
Element
( formula units )
Element
 
( no unit )
3 Si
4 N
Measurement Method: Reported Formula
Evaluation Status: Unevaluated

Si3N4

Material number 3 of 3
in SCD Citation Number: Z00042
Density (mass)
Temperature
 
( °C )
Density
 
( g cm-3 )
25 3.24
Measurement Method: Unknown
Evaluation Status: Unevaluated

Si3N4

Material number 3 of 3
in SCD Citation Number: Z00042
Elastic Modulus
Temperature
 
( °C )
Elastic
Modulus
( GPa )
25 314
Measurement Method: Transient impulse
Evaluation Status: Evaluated by acceptance criteria

Si3N4

Material number 3 of 3
in SCD Citation Number: Z00042
Flexural Strength
Temperature
 
( °C )
Crosshead
Speed
( cm/s )
Flexural
Strength
( MPa )
25 0.0064 538
1300 0.0064 604
1450 0.0064 453
1300 0.00004 551
1450 0.00004 213
Measurement Method: Four-point bend test
Evaluation Status: Evaluated by acceptance criteria
Cautions:
Standard deviations ranged from 12 to 97 MPa and averaged 60 MPa. Failures occurred primarily at tensile surface flaws, but also at edge flaws and subsurface inclusions.

Si3N4

Material number 3 of 3
in SCD Citation Number: Z00042
Fracture Toughness
Temperature
 
( °C )
Fracture
Toughness
( MPa m1/2 )
25 3.8
Measurement Method: Vickers indentation
Evaluation Status: Unevaluated

Si3N4

Material number 3 of 3
in SCD Citation Number: Z00042
Hardness
Temperature
 
( °C )
Hardness
 
( GPa )
25 13.9
Measurement Method: Vickers indentation
Evaluation Status: Unevaluated

Si3N4

Material number 3 of 3
in SCD Citation Number: Z00042
Thermal Expansion
Temperature
 
( °C )
Thermal
Expansion
( 10-6 K-1 )
25-1450 3.4
Measurement Method: Dilatometry
Evaluation Status: Evaluated by acceptance criteria

Si3N4

Material number 3 of 3
in SCD Citation Number: Z00042
Weibull Modulus
Temperature
 
( °C )
Crosshead
Speed
( cm/s )
Weibull
Modulus
( no unit )
25 0.0064 6
1300 0.0064 13
1450 0.0064 12
1300 0.00004 9
1450 0.00004 6
Measurement Method: Four-point bend test
Evaluation Status: Evaluated by acceptance criteria