NIST Standard Reference Database 30
Last Update to Data Content: 2002
"Formation and Characteristics of Silicon Nitride-Lithium Aluminum Silicate Ceramics: Part II, Mechanical and Thermal Properties," D.J. Kim, P. Greil, and G. Petzow, Advanced Ceramic Materials, Vol. 2 [4], pp. 822-826 (1987), published by American Ceramic Society.Language: English
Silicon nitride ceramics with the grain-boundary phase β-eucryptite, LiAlSiO4, or β-spodumene, LiAlSi2O6, were produced by pressureless sintering α-Si3N4 (H.C.Stark, FRG, LC 10, 98.2% purity), SiO2 (Ventron, FRG, 88316, 99.9% purity), and LiAlO2 powder mixtures. Al2O3 (Alcoa A 16, 99.9% purity) was prereacted with Li2CO3 (Ventron, FRG, 44124, 99% purity) to form LiAlO2. Material #1 was sintered at 1800 °C giving β-solid solution/glass, β-LiAlSi2O6. Material #2 was sintered at 1700 °C giving α-solid solution/glass, β-LiAlSiO4. Material #3 was sintered at 1700 °C giving α-solid solution/glass, β-LiAlSiO4. Material #4 was sintered at 1500 °C giving α-solid-solution/glass, β-LiAlSiO4. For some specimens, devitrified annealing was conducted for up to two hours in flowing N2 at temperatures from 900 °C to 1300 °C.
Samples were tested using "a dilatometer with a linear variable differential transformer (Theta Industries, Port Washington, NY) and a graphite heated furnace (FP 12, Astro Industries, Santa Barbara, CA). Temperature was measured with a B/C-thermocouple (BGT-2, Astro Industries). Bars 20 mm long were tested in an Ar atmosphere against an Al2O3 standard."Ultrasonic pulse echo method
The authors cited ASTM E 494-75, Measuring Ultrasonic Velocity in Materials, and summarized their procedure as follows. The measurement was made by ultrasonic pulse-echo method using conventional equipment (USIP 11, Krautkramer, Federal Republic of Germany). Ground specimens 2.5 mm thick were used in air.Four-point bend test
The measurements were made by four-point bend method. 7/20 mm roller spans, loading rate = 0.1 mm/min in air. At least 19 specimens were used for each material.Indentation strength
The authors cited P. Chantikul et al., J. Am. Ceram. Soc. 64 [9] (1981) 539-543 and summarized the procedure as follows. Specimens were subjected to Vickers indentations at five loads (40 N to 400 N) and then tested in 3-point bending, span of rollers = 12 mm, loading rate = 0.1 mm/min. Samples were cut to 2.5 mm x 3.5 mm x 35 mm from bars 10 mm x 20 mm x 50 mm; edges were manually ground and tensile surfaces were polished with 1 µm diamond paste; then the specimens were indented with a Vickers diamond pyramid indenter (Zwick-1474) in air.
| Amount of Element ( formula units ) |
Element ( no unit ) |
|---|---|
| 3 | Si |
| 4 | N |
| Devitrified |
Elastic Modulus ( GPa ) |
|---|---|
| no | 267±15 |
| yes | 268±15 |
| Devitrified |
Flexural Strength ( MPa ) |
|---|---|
| no | 588 ± 48 |
| yes | 635 ± 51 |
| Devitrified |
Fracture Toughness ( MPa m1/2 ) |
|---|---|
| no | 4.19 ± 0.13 |
| yes | 5.61 ± 0.11 |
| Devitrified |
Hardness ( GPa ) |
|---|---|
| No | 14.25 ± 0.25 |
| Yes | 14.28 ± 0.25 |
No method details were noted.
| Temperature Interval ( °C ) |
Measurement Cycle |
Devitrified |
Thermal Expansion ( 10-6 K-1 ) |
|---|---|---|---|
| 40-700 | Heating | no | 3.36 |
| 40-1200 | Cooling | no | 3.22 |
| 40-1200 | Heating | yes | 3.22 |
| 40-1200 | Cooling | yes | 3.16 |
| Amount of Element ( formula units ) |
Element ( no unit ) |
|---|---|
| 3 | Si |
| 4 | N |
| Devitrified |
Elastic Modulus ( GPa ) |
|---|---|
| no | 265±15 |
| yes | 266±15 |
| Devitrified |
Flexural Strength ( MPa ) |
|---|---|
| no | 422 ± 45 |
| yes | 379 ± 32 |
| Devitrified |
Fracture Toughness ( MPa m1/2 ) |
|---|---|
| no | 4.20 ± 0.12 |
| yes | 3.80 ± 0.13 |
| Devitrified |
Hardness ( GPa ) |
|---|---|
| No | 14.25 ± 0.25 |
| Yes | 14.25 ± 0.25 |
| Temperature Interval ( °C ) |
Measurement Cycle |
Devitrified |
Thermal Expansion ( 10-6 K-1 ) |
|---|---|---|---|
| 40-700 | Heating | no | 3.49 |
| 40-1200 | Cooling | no | 2.72 |
| 40-1200 | Heating | yes | 3.15 |
| 40-1200 | Cooling | yes | 3.00 |
| Amount of Element ( formula units ) |
Element ( no unit ) |
|---|---|
| 3 | Si |
| 4 | N |
| Devitrified |
Elastic Modulus ( GPa ) |
|---|---|
| no | 252±15 |
| yes | 261±15 |
| Devitrified |
Flexural Strength ( MPa ) |
|---|---|
| no | 404 ± 25 |
| yes | 365 ± 36 |
| Devitrified |
Fracture Toughness ( MPa m1/2 ) |
|---|---|
| no | 4.08 ± 0.15 |
| yes | 3.41 ± 0.10 |
| Devitrified |
Hardness ( GPa ) |
|---|---|
| No | 14.20 ± 0.25 |
| Yes | 14.18 ± 0.25 |
| Temperature Interval ( °C ) |
Measurement Cycle |
Devitrified |
Thermal Expansion ( 10-6 K-1 ) |
|---|---|---|---|
| 40-700 | Heating | no | 3.58 |
| 40-1200 | Cooling | no | 2.94 |
| 40-1200 | Heating | yes | 3.06 |
| 40-1200 | Cooling | yes | 2.55 |
| Amount of Element ( formula units ) |
Element ( no unit ) |
|---|---|
| 3 | Si |
| 4 | N |
| Devitrified |
Elastic Modulus ( GPa ) |
|---|---|
| no | 212±15 |
| yes | 220±15 |
| Devitrified |
Flexural Strength ( MPa ) |
|---|---|
| no | 250 ± 18 |
| yes | 234 ± 20 |
| Devitrified |
Fracture Toughness ( MPa m1/2 ) |
|---|---|
| no | 3.55 ± 0.09 |
| yes | 3.14 ± 0.12 |
| Devitrified |
Hardness ( GPa ) |
|---|---|
| No | 11.36 ± 0.25 |
| Yes | 11.36 ± 0.25 |
| Temperature Interval ( °C ) |
Measurement Cycle |
Devitrified |
Thermal Expansion ( 10-6 K-1 ) |
|---|---|---|---|
| 40-70 | Heating | no | 3.62 |
| 40-1200 | Cooling | no | 2.39 |
| 40-1200 | Heating | yes | 2.69 |
| 40-1200 | Cooling | no | 1.59 |