Aluminium oxide — the workhorse oxide ceramic. Hard, wear-resistant, electrically insulating, chemically inert and stable to 1750 °C. Densities and purities from 95% up to 99.99% Al₂O₃.
Used for: furnace tubes · crucibles · insulators · atomising nozzles · kiln furniture · seal rings · wear plates
Aluminium oxide (Al₂O₃) underpins one of the most important groups of technical oxide ceramics. As modern processes push hotter, harder and more chemically aggressive, densely sintered alumina has become the default oxide-ceramic specification — combining high strength and hardness, temperature stability, electrical insulation, wear and friction resistance, and corrosion resistance at elevated temperatures.
Industrial alumina parts are typically formulated with additions of silica or magnesia. Anderman’s densely sintered grades span 95% to 99.9% Al₂O₃; higher purities deliver higher temperature capability, better wear performance and improved dielectric strength. Below 96% the secondary glassy phase progressively reduces creep resistance and high-temperature strength.
Dense alumina is shaped by isostatic and uniaxial pressing, extrusion, slip casting and injection moulding. After firing it is hard (HV ~1700) so finishing is done by diamond grinding. We hold stock in rods, tubes, thermocouple sheaths, plates, crucibles and insulators, and produce bespoke shapes to customer specification.
Furnace tubes and thermocouple protection sheaths to 1750 °C, atomising and metering nozzles, seal faces and wear plates, electrical and RF insulators, and lab-grade crucibles. Where chemistry, temperature and abrasion combine, dense alumina is usually the first material to evaluate.
| Grade | Purity | Max temp | Density | Hardness | Typical use | Find products |
|---|---|---|---|---|---|---|
| EA999 | 99.9% Al₂O₃ | 1800 °C | 3.96 | 1800 HV | Severe-duty high-temp & semiconductor | → Find products |
| EA998 | 99.8% Al₂O₃ | 1800 °C | 3.95 | 1750 HV | High-purity furnace & lab | → Find products |
| EA995 | 99.5% Al₂O₃ | 1750 °C | 3.90 | 1700 HV | General high-performance, the default | → Find products |
| EA96 | 96% Al₂O₃ | 1700 °C | 3.72 | 1450 HV | Cost-balanced wear & insulation | → Find products |
| EA95 | 95% Al₂O₃ | 1700 °C | 3.70 | 1400 HV | Wear plates, liners, general industrial | → Find products |
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Move up in purity when temperature, wear or dielectric performance is the deciding factor; stay lower when geometry and cost matter more than peak property. EA995 is the typical default; EA999 is specified where the secondary phase would compromise creep, dielectric strength or chemical compatibility.
Dense alumina has a moderate thermal-expansion coefficient (~8 × 10⁻⁶/K) and modest thermal conductivity, so large temperature swings can crack it. For rapid heat/cool cycles consider porous alumina, mullite or fused silica.
Yes. High-purity grades (EA995 and above) accept moly-manganese metallisation followed by nickel and braze layers, producing vacuum-tight metal-ceramic seals used in lamps, vacuum feedthroughs and electronics packages.
Continuous use to 1700–1750 °C with appropriate grade selection. Above this, strength falls and creep accelerates; specify mullite or rare-earth oxides for sustained service at higher temperatures.
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Tell us your operating temperature, the chemistry it'll see and any mechanical loads. We'll specify a grade — or recommend an alternative material — and link you directly to matching products.
