An alumina ceramic flange is a precision ceramic connection part used to support, locate, seal or electrically isolate tubes, heaters, chambers and mounting structures in high-temperature equipment. It is selected when metal flanges may deform, oxidize, conduct current or create contamination risk under heat, corrosion or electrical load.
Match the Alumina Ceramic Flange to Its Equipment Function
A ceramic flange locates, supports or electrically isolates an equipment interface. A sealing face can be included with the specified mating surface and seal arrangement.
| Equipment need | What the flange contributes | Selection basis |
|---|---|---|
| Furnace-tube mounting | A ceramic locating or support interface at the tube end. | Tube/bore fit, support position, load and thermal movement. |
| Heater or electrode mounting | Electrical isolation between conductive hardware. | Insulation path, creepage/clearance, temperature and the assembly electrical test. |
| Vacuum or controlled-atmosphere equipment | A drawing-defined contact face within the joint. | Mating surface, seal, fastening load and the agreed assembly leak test. |
| Chemical/process connection | A ceramic contact or insulating interface for the selected medium. | Medium composition, exposure, temperature, seal compatibility and structural duty. |
Alumina grade and machining state establish the ceramic component specification; joint performance is qualified with its mating hardware, seal and operating conditions.
Alumina Material Data for Flange Selection
Compare thermal expansion and electrical references for the interface duty. Expand the composition and mechanical data when selecting the grade or defining material acceptance.
| Property/basis | 99.7% Al₂O₃ | 99.5% Al₂O₃ | 99% Al₂O₃ | 96% Al₂O₃ | 95% Al₂O₃ |
|---|---|---|---|---|---|
| Nominal Al₂O₃, wt% | 99.70 | 99.50 | 99.00 | 96 | 95 |
| IEC 60672-3 composition grouping | C799 | C799 | C795 | C795 | C795 |
| Density, g/cm³; typical | 3.94 | 3.90–3.92 | 3.80–3.91 | 3.70 | 3.75 |
| Flexural strength, MPa; 20°C; typical | 330 | 320–350 | 300–320 | 300 | 280 |
| Compressive strength, MPa; 20°C; typical | 2500 | 2400 | 2400 | 2000 | 2000 |
| Young’s modulus, GPa; typical | 370 | 365 | 355 | 275 at 20°C | 340 |
| KIC, MPa·m½; method-dependent | 3.6 | 3.5 | 3.3 | 3.5 at 20°C | 3.0 |
| Water absorption, %; selection limits except 96% | ≤0.05 | ≤0.10 | ≤0.10 | ≈0; typical, rounded | ≤0.20 |
*IEC C795/C799 identifies composition grouping. Use the selected material grade, order drawing and agreed tests for finished-part acceptance; the 96% water-absorption entry is a rounded typical value.
Thermal Material Reference
| Property / basis | 99.7% Al₂O₃ | 99.5% Al₂O₃ | 99% Al₂O₃ | 96% Al₂O₃ | 95% Al₂O₃ |
|---|---|---|---|---|---|
| Thermal conductivity, W/(m·K); typical | 35–40 at 25°C | 30–38 at 25°C | 24 at 25°C | 25 at 20°C | 18–25 at 25°C |
| Mean CTE, 10⁻⁶/K; stated interval | 7.6; 25–800°C | 7.6; 25–800°C | 7.2; 25–800°C | 8.2; 25–1000°C | 7.6; 25–800°C |
| Material service-temperature guide, °C; application-dependent | 1700 | 1650 | 1600 | 1600 maximum in air | 1400 |
Electrical Reference for Insulating-Interface Enquiries
| Property/basis | 99.7% Al₂O₃ | 99.5% Al₂O₃ | 99% Al₂O₃ | 96% Al₂O₃ | 95% Al₂O₃ |
|---|---|---|---|---|---|
| Dielectric strength, kV/mm; typical; specimen basis | 10; 5 mm | 10; 5 mm | 10; 5 mm | 8.3; AC, 6.35 mm | 10; 5 mm |
| Relative permittivity; 1 MHz; typical | 9.8 at 25°C | 9.7 at 25°C | 9.6 at 25°C | 9.0 at room temperature | 9.4 at 25°C |
| Dissipation factor; 1 MHz | <0.0001 at 25°C | <0.0001 at 25°C | 0.0006 at 25°C | 0.0002 at 20°C | 0.0004 at 25°C |
| Volume resistivity, Ω·cm; 20°C | >10¹⁴ | >10¹⁴ | >10¹⁴ | 10¹⁴; typical | >10¹² |
*Set the finished-interface working voltage from the actual geometry and qualification test. Define AC/DC/pulse conditions, frequency, electrodes, temperature/humidity, contamination, insulation path and creepage/clearance.
Material Grade and Property Reference
Alumina ceramic flanges are commonly produced from 95%, 96%, 99% or 99.5% Al₂O₃ depending on temperature, insulation requirement, chemical exposure, cleanliness requirement and budget.
- 95% Alumina
Cost-effective for industrial flanges, furnace fixtures and general insulation where high purity is not required. - 96% Alumina
Balanced choice for heater assemblies and tube interfaces with stable performance and practical cost control. - 99% Alumina
For higher-temperature or cleaner applications requiring improved purity and lower contamination risk. - 99.5% and 99.7% Alumina
Selected when higher purity or more demanding technical performance is needed.
Selection Note:
Confirm grade with geometry, sealing method, atmosphere and cost target. Higher purity is not always necessary for mechanical fit or industrial insulation.
Alumina Ceramic Flange Specifications
| Alumina Ceramic Flange | ||
| Item No. | Diameter (mm) | Thickness (mm) |
| AT-YHL-FL01 | Customize | |
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Inspection and Packaging for Flanges
Agree pre-shipment checks for critical dimensions, sealing/contact faces, hole patterns, edges and identification. Define the required report fields, sampling and functional tests for the order.
Protect sealing faces, bore and bolt-hole edges from direct contact. Use geometry-appropriate support, cushioning and separation to prevent ceramic-to-ceramic contact and concentrated transport loads. The illustration shows a packing sequence; agree the actual inner protection and outer packaging for the order.
