92% Alumina、95% Alumina、99% Alumina
A brief introduction to 92% alumina, 95% alumina, and 99% alumina ceramics.
92% Alumina, 95% Alumina, and 99% Alumina
92% Alumina, 95% Alumina, and 99% Alumina are common grades of alumina ceramics (high-alumina ceramics) classified according to their aluminum oxide (Al₂O₃) content; the numerical value directly represents the mass percentage of Al₂O₃. Alumina content is the key parameter determining the performance of ceramic materials, and these different grades exhibit significant variations in terms of mechanical strength, thermal resistance, electrical insulation properties, and application scenarios.
Basic Classification
Grade | Al₂O₃ Content | Common Name | Main Crystalline Phase |
92 Alumina | ≥92% | High-Alumina Ceramic | α-Al₂O₃(Corundum) |
95 Alumina | ≥95% | Corundum Ceramic | α-Al₂O₃(Corundum) |
99 Alumina | ≥99% | Pure Corundum Ceramic | α-Al₂O₃(Corundum) |
Additionally, there are grades with even higher content—specifically 99.5%, 99.7%, and 99.9% or higher—classified as high-purity alumina ceramics. When the Al₂O₃ content exceeds 99%, the material is designated as pure corundum porcelain; grades with a content ranging between 75% and 99% are collectively referred to as high-alumina ceramics.
As the Al₂O₃ content increases, the levels of impurities (particularly SiO₂, Na₂O, and Fe₂O₃) must be strictly controlled; otherwise, the electrical and high-temperature properties of the material will be compromised.
Performance Comparison
Performance Parameters | 92% Alumina | 95 Alumina | 99 Alumina |
Bulk Density (g/cm³) | 3.60-3.65 | 3.65-3.75 | ≥3.75 |
Flexural Strength (MPa) | 250-300 | 300-350 | 350-450 |
Rockwell Hardness (HRA) | 80-85 | 85-90 | 90-95 |
Service Temperature (°C) | 1200-1300 | 1300-1400 | 1400-1600 |
Insulation Properties | Good | Excellent | Superior |
Wear Resistance | Good | Excellent | Superior |
Cost | Low | Moderate | High |
Overall performance improves as the Al₂O₃ content increases: 99% alumina exhibits the highest hardness and strength, along with superior wear resistance and high-temperature stability; 92% and 95% alumina offer excellent comprehensive performance and a higher cost-performance ratio.
Typical Applications
Grade | Typical Applications |
92 Alumina | Wear-resistant ceramic liners, chemical pipeline linings, grinding media (grinding balls, lining bricks), general-purpose insulating components |
95% Alumina | Corrosion- and wear-resistant components, textile ceramics, electrical insulators, vacuum interrupter envelopes, spark plug insulators |
99% Alumina | High-temperature crucibles, refractory furnace tubes, ceramic bearings, sealing components, integrated circuit substrates, high-frequency insulating materials, artificial joints |
99% alumina ceramics are primarily utilized in demanding operating environments characterized by high temperatures, severe abrasion, and strict insulation requirements; conversely, 95% and 92% alumina ceramics have become the most widely adopted alumina ceramic materials in industrial applications, owing to their excellent balance of comprehensive performance and moderate cost.
Summary
The fundamental distinction among 92%, 95%, and 99% alumina ceramics lies in their alumina content, which, in turn, dictates their differing mechanical properties, thermal resistance, electrical insulation capabilities, and application scenarios. When selecting a material, a comprehensive assessment should be conducted based on the specific temperature, abrasion, and insulation requirements of the actual operating conditions, while also taking cost constraints into account.