Aluminum Oxide
Aluminum Oxide (Alumina) & Alumina Products
Alumina, also commonly referred to as sapphire ceramic material, is one of the most versatile ceramic materials because of its high temperature service limit along with its chemical, electrical and mechanical properties. It is also relatively low cost, is easily formed and finished using a number of fabrication methods including injection molding for low cost, high volume production runs. It is often compounded with silica or trace elements to enhance its properties or fabrication and commonly will range from 92% to 99.8% Al2O3. Higher purity, gel cast material can be found under our REPTON brand.
Alumina machined ceramic components can be formed by single axis pressing, isostatic pressing, injection molding, slip casting, or extrusion. Parts can "green machined" to near net size before firing and then "hard" ground using diamond tooling to tolerances less than 0.0002" (0.005 mm). Special grades of alumina can be metallized and/or brazed to metal parts.
For special grades of isopressed alumina for plain and metallized tubes see our ISO ALUMINA Data Sheet and for very large gel cast shapes and ultra high purity (99.99%) see our REPTON and SEMICONDUCTOR pages.
Alumina Oxide (Alumina) Properties
| Properties | Condition | Units | 960P | 975P | 998P | 96S | IP-95 | IP-99 |
| Mechanical | ||||||||
| Al2O3 Minimum | - | % | 96.0 | 97.6 | 99.8 | 96.0 | 99.5 | 95.0 |
| Bulk Density | 20°C | g/cm3 | 3.67 | 3.72 | 3.96 | 3.77 | 3.65 | 3.85 |
| Tensile Strength | 20°C | MPa | 205 | 205 | 220 | nd | 160 | 240 |
| Flexural (Bending) Strength | 20°C | MPa | 375 | 375 | 410 | 295 | 300 | 350 |
| Elastic Modulo | 20°C | GPa | 300 | 355 | 375 | nd | 300 | 350 |
| Hardness | 20°C | MPa | 10 | 12 | 14 | nd | nd | nd |
| Fracture Toughness | 20°C | MPa-m1/2 | 4-5 | 4-5 | 4-5 | nd | nd | nd |
| Porosity | 20°C | % | 0 | 0 | 0 | 0 | 0 | 0 |
| Thermal | ||||||||
| Max. Working temperature Coef. Thermal Expansion |
- | °C | 1600 | 1650 | 1700 | na | 1500 | 1700 |
| 25-300°C | 10-6 /°C | 7.1 | 7.2 | 7.8 | 6.7 | 7.1 | 7.8 | |
| 25-1000°C | 10-6 /°C | 7.4 | 7.7 | 8.1 | 7.4 | 8.1 | 8.0 | |
| Thermal Conductivity | 20°C | W/m°K | 24 | 26 | 28 | 28.6 | 20 | 25 |
| Electrical | ||||||||
| Dielectric Strength | 2.5mm tk | ac-kv/mm | 9.2 | 9.2 | 10 | 30 | 20 | 20 |
| Dielectric Constant | 1 MHz | - | 9.0 | 9.4 | 9.7 | 9.8 | 9.0 | 9.2 |
| Volume Resistivity | 20°C | Ohm-cm | >1014 | >1014 | >1014 | >1014 | >1014 | >1015 |
| 300°C | Ohm-cm | 109 | 109 | 1010 | 1012 | nd | nd | |
| 1000°C | Ohm-cm | 106 | 106 | 106 | 107 | nd | nd | |
| Loss Tangent | 1 MHz | - | 0.028 | 0.012 | 0.009 | 0.0015 | 0.0003 | 0.0002 |
| Dissipation Factor | 1 MHz | - | 0.0003 | 0.0002 | 0.0001 | - | - | - |
| Electrical | IP,DP,CIM,SC,EX | TC | IP | |||||
| IP= Isopress DP= Dry press SC= Slip cast CIM= Ceramic injection molding TC= Tape cast EX= Extrusion | ||||||||
| Chemical names and formulas: | |
| formula | Al2O3 |
| name | aluminum oxide |
| IUPAC name | oxo-oxoalumanyloxyalumane |
| alternate names | alumina | keto-ketoalumanyloxy-alumane | |
| oxo-oxoalumanyloxy-alumane | | |
| oxo-oxoalumanyloxyalumane | |
| mass fractions | Al (aluminum) 52.9% | O (oxygen) 47.1% |
| Structure Diagram | |
 |
|
| Basic Properties | |
| Molecular Weight | 101.9613 g/mol |
| Phase | solid (at STP) |
| Melting point | 2040° C |
| Thermodynamic properties | |
| Specific heat of fusion | 1.09 kj/g |
| Chemical identifiers | |
| GAS number | 1344-28-1 |
| PubChem CID | 14769 |
| Toxicity properties | |
| Odor | odorless |
| Short-term exposure limit | 20 mg/m3 |
