HIGH ALUMINA
| HIGH ALUMINA | |||||
|---|---|---|---|---|---|
| GROUP | C. 700 C. 800 | ||||
| SUB GROUP | 780 | 786 | 799 | ||
| FEATURE OF COMPOSITION | Al₂O₃ 75 - 80% | Al₂O₃ - 92% | Al₂O₃ - 99.5% | ||
| APPLICATION RANGE | Good electrical & mechanical properties, suited to general-purpose applications. | Good mechanical and thermo properties, combined with high wear resistance, suitable for rotating or sliding parts because of low coefficient of friction. | Very good electrical & mechanical properties, high and wear resistance, suite for severe applications in all conditions. | Exceptional electrical and mechanical properties, superior chemical and textile application | |
| PROPERTIES | |||||
| COLOUR | Pink / White | Brown | Pink | White | |
| POROSITY (Vol. %) | - | 0 | 0 | 0 | |
| BULK DENSITY (g/cm²) | 3.40 | 3.40 | 3.65 | 3.90 | |
| HARDNESS (Mohs Scale) | 8 | 8 | 9 | 9 | |
| FLEXURAL STRENGTH (N/mm²) | Unglazed | 200 | 200 | 260 | 370 |
| Glazed | - | - | - | - | |
| MODULUS OF ELASTICITY (103 N/mm²) | 200 | 200 | 240 | 260 | |
|
THERMAL EXPANSION LINER COEFFICIENT (10⁻⁶ K⁻¹) |
a20 - 100°C | 7.10 | 6.35 | 7.10 | 7.10 |
| a20 - 300°C | 6.40 | 6.20 | 6.40 | 6.40 | |
| a20 - 600°C | 7.35 | 7.15 | 7.35 | 7.35 | |
| a20 - 800°C | 7.65 | 7.65 | 7.65 | 7.90 | |
| THERMAL SHOCK RESISTANCE MIN. (K) | 140 | 140 | 150 | 150 | |
| SPECIFIC HEAT CAPACITY (20-100C) | 850 to 900 | 850 to 1050 | 850 to 1050 | 850 to 1050 | |
| THERMAL CONDUCTIVITY (20-100C) | 13 | 15 | 20 | 33 | |
| DIELECTRIC STRENGTH METHOD A (KV/mm) | 15 to 20 | 15 to 20 | 15 to 20 | 15 to 20 | |
| RELATIVE PERMITTIVITY (48 to 62Hz) | 8.0 | 8.0 | 9.0 | 9.0 | |
| DISSIPATION FACTOR AT 20C (10³) | 48 - 62 Hz | 1 | 1 | 0.5 | 0.4 |
| 1 KHz | - | - | - | - | |
| 1 MHz | 0.8 | 0.8 | 0.4 | 0.3 | |
| VOLUME RESISTIVITY IN TERMS OF TEMPERATUR E (D.C.)cm |
20°C | 10¹⁴ | 10¹⁴ | 10¹⁴ | 10¹⁴ |
| 200°C | 10¹² | 10¹² | 10¹² | 10¹² | |
| 600°C | 10⁷ | 10⁷ | 10⁸ | 10⁸ | |