TABLE OF CONTENTS Intensive development of ceramic materials has increased the availability of well-characterised engineering ceramics capable of use over a range of temperatures and atmospheres. Table 27.1 summarises the properties of the most commonly used engineering ceramics while Table 27.2 gives more information about a range of ceramics. However, the data in the tables should be regarded as representative since actual values are a strong function of exact composition and microstructure. Furthermore, since these materials are often used at high temperatures the properties at use rather than room temperature (RT) are important.
| Type | Melting or decomposition temperature, C | Density gcm -3 | Thermal conductivity W/mK ( measured temperature or range, C) | Thermal expansion ( 10 -6 K -1) ( measured temperature or range, C) | Young's modulus GPA | Strength MPa ( technique, measured temperature or range, C) | K Ic MPaM 1/2 |
|---|---|---|---|---|---|---|---|
| Silicon Carbide | |||||||
| Hot Pressed | 2200 | 3.2 | 50 (600) | 4.55 | 440 450 | 640 650 (bend, 20 1 400) | 5.7 |
| Sintered |
| 3.1 | 55 (600) | 4.5 4.9 (20 1 500) | 395 410 | 430 450 (bend, 20 1 400) | 3 5 |
| Reaction Bonded |
| 3 |
| 4.2 4.3 (20 1 500) | 280 390 | 350 540 (bend, 20) | 4.4 5 |
| Silicon Nitride | |||||||
| Hot Pressed | 1 800d | 3.2 3.9 | 15 50 (20) | 2 3 (20 1 000) | 280 320 | 400 1000 (bend, 20) | 3.4 8.2 |
| Sintered | 1 800d | 3.13 |
| 3.5 | 245 | 420 | 4.8 |
| Reaction Bonded | 1 800d | 2.2 3.2 | 3 30 (20) | 2 3 (20 1 000) | 100 220 | 190 400 (bend, 20) |
