Material Overview
Alumina (Al₂O₃) is a wear-resistant industrial ceramic, and prized for their exceptional hardness, thermal stability, and chemical resistance. Alumina is the most widely used material in advanced ceramics, with purity ranging from 75% to 99.8%. Alumina with a purity of more than 95% is considered high-purity alumina. Alumina with a purity below 95% mainly takes into account its economy from a cost perspective while ensuring certain performance.. these high-purity alumina ceramics are widely used in industries requiring high wear resistance, electrical insulation, and thermal management. Key applications span aerospace, medical devices, semiconductor manufacturing, and refractory systems.
Technical Data Table
| Property | 96% Alumina | 99% Alumina | 99.8% Alumina |
| Density (g/cm³) | >3.65 | >3.8 | >3.92 |
| Flexural Strength (MPa) | >280 | >310 | >361 |
| Modulus of Elasticity (GPa) | 303 | 350 | 380 |
| Thermal Conductivity (W/m·K) | 24 | 29 | 31 |
| Max. service temperature (℃) | 1500 | 1600 | 1750 |
| Dielectric Strength (kV/mm) | >15 | >17 | >20 |
Initial products of alumina can be made by injection molding, dry pressing，hot injection molding , isostatic pressing, slip casting ,tape casting and extrusion forming . In the green or billet state, alumina is processed into complex geometric shapes through these different forming processes. The initial molded products are then sintered to solidify the structure. The sintered alumina products are further precision-machined using diamond grinding methods according to the customer’s technical details. In addition, if the alumina products are to be connected to metals or other ceramics, metallization and brazing technologies can be used to achieve this.
Among alumina ceramic products, the most commonly used product forms are alumina substrates, alumina plates, metallized alumina ceramics and alumina tubes，these products make full use of the excellent properties of alumina. The following product examples show other more product forms of alumina ceramics.
Key Features
- High-Temperature Resistance: Operates up to 1,600°C without deformation, ideal for kiln linings and furnace components.
- Electrical Insulation: Dielectric strength >15 kV/mm, critical for circuit substrates and high-voltage insulators.
- Wear Resistance: Vickers hardness of 1,380–1,700 HV, outperforming stainless steel by 10x in abrasive environments.
- Chemical Inertness: Resists acids, alkalis, and molten metals, ensuring longevity in corrosive settings.
Applications
- Electronics: Substrates for integrated circuits and microwave devices due to low signal loss.
- Medical: Biocompatible implants and surgical tools with FDA-compliant surfaces.
- Industrial: High-precision components for pumps, valves, and cutting tools.
- Energy: Refractory linings for reactors and solar thermal systems.
Manufacturing & Customization
- Advanced Processing: Jinghui Ceramics excels in the precision and complex processing of industrial ceramic products, such as multi-axis machining centers, drilling, grinding, milling, polishing, sawing, tapping, thread processing and turning, etc., which can meet the high-specification technical requirements of your products to the greatest extent.
- Material Enhancements: Doping with ZrO₂ improves fracture toughness and corrosion resistance.
Alumina ceramics outperform metals due to their ultra-high melting point (2,072°C) and low thermal expansion (6~8×10⁻⁶/°C). For example, alumina furnace tubes withstand cyclic heating to 1,600°C without cracking, unlike stainless steel, which oxidizes above 500°C. Additionally, their non-reactive nature prevents contamination in semiconductor processing.
Higher alumina content (99%+) enhances mechanical and thermal properties. For instance, 99.8% alumina achieves a flexural strength of 361 MPa, compared to 280 MPa for 96% grades. This makes ultra-pure alumina ideal for aerospace bearings and laser-cut components, where precision and durability are critical. Lower-purity grades (85–95%) are cost-effective for refractory bricks and grinding media.
Based on our existing forming technology (dry pressing, hot pressing, tape casting, extrusion, injection molding), we can achieve complex shapes including: threads, buckles, multiple holes, thin walls, long/tubular shapes, regular cross-section continuous structures, grooves and through holes on the plane, axisymmetric structures, etc. We cannot achieve: suspended structures, closed cavities, sharp angle details (3D printing or gel injection molding is required).
- Electronics: Alumina substrates reduce signal loss in high-frequency circuits (dielectric loss ≈0.0004 at 1 MHz).
- Energy: Insulators for power transmission systems withstand 15 kV/mm without breakdown.
- Automotive: Spark plug insulators improve ignition efficiency by 20%.