ADCERAX manufactures custom square and rectangular alumina ceramic tubes used as the insulating ceramic electrode tube inside corona treatment equipment.
Share your drawing or an old-part photo with the outer size, inner bore, wall thickness, length, purity and quantity, and our engineers review every RFQ before quoting.
It’s a hollow square or rectangular alumina tube that does two jobs in a corona electrode area: insulate the high-voltage zone, and fit the cassette or holder it sits in. That fit is why the shape matters — a round tube in the same material usually won’t seat in a square cassette.
Most jobs reach us one of two ways: a new OEM profile from a drawing, or a copy of an electrode tube that has cracked or gone out of production. A photo is enough to start the conversation, but we need measured dimensions and tolerances before we can quote.
What it isn’t: a round furnace or thermocouple tube, a generic insulator tube, or a finished corona machine.
The following dimensions are based on confirmed production. They are not a universal size list for every square or rectangular alumina ceramic tube. Final quotation still depends on drawing review, inner bore, wall thickness, length, tolerance request, machined features, material grade, quantity and destination.
Type 1 – Al₂O₃ Corundum Square Tubes
| Item No. | Width（mm） | Height（mm） | Thickness（mm） | Length（mm） |
| TE-AT-50001 | 7 | 7 | 1.5 | ≤3500 |
| TE-AT-50002 | 8 | 6 | 1 | ≤3500 |
| TE-AT-50003 | 8.7 | 6.3 | 1.1 | ≤3500 |
| TE-AT-50004 | 9.5 | 9.5 | 2 | ≤3500 |
| TE-AT-50005 | 10 | 10 | 5 | ≤3500 |
| TE-AT-50006 | 11 | 8 | 2.5 | ≤3500 |
| TE-AT-50007 | 13 | 10 | 2 | ≤3500 |
| TE-AT-50008 | 15 | 15 | 4 | ≤3500 |
| TE-AT-50009 | 16.5 | 16.5 | 5 | ≤3500 |
| TE-AT-50010 | 23 | 16 | 3 | ≤3500 |
| TE-AT-50011 | 25 | 25 | 3.5 | ≤3500 |
| TE-AT-50012 | 32 | 27 | 3.5 | ≤3500 |
| TE-AT-50013 | 36 | 30 | 3 | ≤3500 |
| TE-AT-50014 | 40 | 30 | 3 | ≤3500 |
Type2 – Square Al2O3 Tubes with Round Bore
| Item No. | Width（mm） | Height（mm） | Bore Dia（mm） | Length（mm） |
| TE-AT-50015 | 6 | 6 | 2.3 | ≤3500 |
| TE-AT-50016 | 8 | 8 | 4.5 | ≤3500 |
| TE-AT-50017 | 8 | 8 | 4 | ≤3500 |
| TE-AT-50018 | 9.5 | 9.5 | 5.2 | ≤3500 |
| TE-AT-50019 | 10 | 10 | 4.5 | ≤3500 |
| TE-AT-50020 | 10 | 10 | 7 | ≤3500 |
| TE-AT-50021 | 18 | 18 | 6 | ≤3500 |
| TE-AT-50022 | 23 | 23 | 8 | ≤3500 |
| TE-AT-50023 | 27 | 27 | 5.5 | ≤3500 |
| TE-AT-50024 | 32 | 32 | 10 | ≤3500 |
| TE-AT-50025 | 40 | 40 | 9 | ≤3500 |
Type3-Square Al2O3 with square bore
| Item No. | Diameter（mm） | Width (mm) | Height (mm) | Length (mm) |
| TE-AT-50026 | 2 | 1.3 | 0.9 | ≤2000 |
| TE-AT-50027 | 10 | 2 | 1 | ≤2000 |
| TE-AT-50028 | 15 | 4 | 3 | ≤2000 |
| TE-AT-50029 | 20 | 3.5 | 3.5 | ≤2000 |
| TE-AT-50030 | 24 | 7 | 6 | ≤2000 |
| TE-AT-50031 | 25.5 | 7.5 | 5 | ≤2000 |
| TE-AT-50032 | 29 | 6 | 4.5 | ≤2000 |
| TE-AT-50033 | 30 | 10 | 8 | ≤2000 |
| TE-AT-50034 | 35 | 10 | 7.5 | ≤2000 |
| TE-AT-50035 | 37.5 | 11 | 11 | ≤2000 |
| TE-AT-50036 | 40 | 9.5 | 7 | ≤2000 |
Note: We offer custom dimensions, shapes, and specifications to meet your specific requirements. Contact our engineering team for consultation.
How long we can go depends on the profile — see the table. It’s a capability guide, not a stock list, and not a promise for every wall, bore or tolerance combination.
| Profile reference | Maximum confirmed length reference | Engineering note |
|---|---|---|
| 80 x 80 mm | Up to 500 mm | Large profile, shorter length range. |
| 55 x 55 mm | Up to 1000 mm | Medium profile, drawing review required. |
| 40 x 40 mm | Up to 2500 mm | Long tube review required for straightness and packing. |
| 25 x 25 mm | Up to 3500 mm | Small profile long-tube capability reference, not a promise for every bore or wall thickness. |
Note: the 2500 mm and 3500 mm figures belong to specific profiles. Don’t read them as a blanket maximum for every square tube or every corona design.
Inside corona treatment equipment, this square or rectangular alumina ceramic tube works as the insulating ceramic electrode tube around the high-voltage discharge area — holding the electrode geometry in place while keeping insulation stable. It is the ceramic tube body only, not a complete corona electrode, cassette or treater. A round tube usually cannot replace a square/rectangular electrode structure.
We can run 95%, 99%, 99.5% and 99.7% Al₂O₃. One thing to keep separate, though: what we can make and what we can certify aren't the same question. If you need a COA, C799, IEC 60672, RoHS or REACH document, tell us up front so we can check batch and paperwork before quoting.
| Property | Unit | 95% Al₂O₃ | 99% Al₂O₃ | 99.5% Al₂O₃ | 99.7% Al₂O₃ |
| Alumina content | % | 95 | 99 | 99.5 | 99.7 |
| Density | g/cm³ | 3.6–3.75 | 3.83 | 3.89 | 3.92 |
| Color | – | White | Ivory | Ivory | Ivory |
| Water absorption | % | 0 | 0 | 0 | 0 |
| Young’s modulus | GPa | ~300 | ~360 | ~370 | ~375 |
| Shear modulus | GPa | ~123 | ~148 | 152 | ~154 |
| Bulk modulus | GPa | ~180 | ~215 | 228 | ~223 |
| Poisson’s ratio | – | 0.22 | 0.22 | 0.22 | 0.22 |
| Compressive strength | MPa | 1910 | 2210 | 2600 | ~2600 |
| Flexural strength | MPa | 260 | 300 | 379 | ~380 |
| Fracture toughness | MPa·m¹/² | ~3.5 | ~4 | 4 | ~4 |
| Hardness (HV) | GPa | 14.5 | 17 | 17 | ~18 |
| Thermal conductivity | W/m·K | 22 | 24 | 35 | 33–38 |
| Thermal shock resistance ΔT | °C | ~200 | ~200 | ~200 | 223 |
| Max use temp (no load) | °C | 1450 | 1680 | ≤1750 | 1760 |
| Coefficient of thermal expansion | 10⁻⁶/°C | 7.6 | 7.6 | 8.4 | 8.4 |
| Volume resistivity | Ω·cm | >1×10¹⁴ | >1×10¹⁴ | >1×10¹⁴ | >1×10¹⁴ |
| Dielectric constant | – | 9.2 | 9.5 | 9.8 | 9.84 |
| Dielectric strength | kV/mm | 15 | 19 | 16.9 | 23.4 |
| Dissipation factor (@1 kHz) | – | ~0.0005 | ~0.0003 | 0.0002 | ~0.0001 |
Typical values for sintered alumina of the stated purity. Properties vary with grain size, sintering process, porosity and test method. Indicative for material selection only; for certified values on a specific part, request an Engineering Review.
Send the drawing or the broken part. We check the section, bore, wall, length, end finish and any slots before we price it.
A photo gets us talking; measured dimensions and tolerances are what we actually quote against.
Need a COA, dimensional report, RoHS, REACH, C799 or IEC 60672? Say so early — we confirm document availability before production.
Long tubes carry their own risk. We review straightness, bowing, edge chipping and export packing before committing to a length.
Technical answers to help to specify a square or rectangular alumina ceramic tube for corona electrode RFQs
No. This page is for the alumina ceramic tube body used in a corona electrode area or ceramic electrode cassette. ADCERAX does not treat it as a complete corona machine or a universal complete electrode assembly.
Please provide a drawing or old-part photo, outer size, inner bore, wall thickness, length, corner design, slots or holes, end finish, tolerance request, purity grade, quantity and destination.
Yes, when the buyer can provide drawings, measured samples, old-part photos, quantity, destination and delivery term preference. ADCERAX should be treated as an engineering RFQ source for planned spare supply or cost comparison, not as an unverified emergency drop-in replacement guarantee.
Not automatically. Corona electrode tubes must match the square or rectangular profile, wall thickness, length, straightness, insulation requirements and assembly design. A generic tube may not fit or perform correctly.
The shape is part of the assembly design. A round alumina tube may use a similar material, but it usually cannot replace a square or rectangular electrode cassette profile without confirming the original equipment geometry.
High-voltage insulation is important for corona electrode applications, but finished-tube dielectric strength depends on wall thickness, surface condition, defects and test method. If a dielectric strength value is required, the test method and acceptance value should be stated in the RFQ.
Only after dimensions and compatibility are confirmed. Long custom ceramic tubes are better handled as planned spare parts or engineering RFQs, especially when straightness, packaging and shipping risk need review.
A photo can start the RFQ discussion, but it cannot replace measured dimensions, tolerance requirements, material grade and application information. Engineering review is still required.
Long square and rectangular alumina tubes need careful review for straightness, bending risk, edge chipping, end protection and export packing. The packing plan should be confirmed according to tube length, profile size, quantity and destination.
We make square and rectangular alumina ceramic tubes to drawing, including non-standard profiles, slots, end finishes and old-part replication. Low-to-mid quantity is supported and every custom request goes through engineering review before quoting. See the RFQ checklist below for the details to send.
| Custom item | What the buyer should provide | Review note |
|---|---|---|
| Profile / outer size | Square or rectangular outer dimensions, drawing or measured sample | Used to check cassette, holder or old-part fit. |
| Inner bore and wall thickness | Inner opening size, wall thickness and any insulation clearance requirement | Affects manufacturability, strength and insulation review. |
| Length | Required tube length and acceptable straightness or bending requirement | Long square tubes need profile-length capability, packing and shipping review. |
| Machined features | Slots, holes, end finish, chamfers, corner design or special edges | Each feature needs drawing-based engineering review. |
| Material and documents | 95%, 99%, 99.5% or 99.7% Al2O3 request, COA, dimensional report, RoHS, REACH, C799 or IEC 60672 requirement | Document availability must be checked before quotation or production confirmation. |
If your project is not this square or rectangular alumina ceramic tube for a corona electrode area, choose the closest RFQ path below:
What to Send for a Faster Engineering RFQ Review
For a faster engineering RFQ review, please share:
Application / equipment (corona treater, electrode cassette, brand & model)
Drawing or an old-part photo
Outer size (A×A or A×B), inner bore, wall thickness
Length and required straightness
Corner type (round/sharp), slots/holes, end finish
Alumina purity (95 / 99 / 99.5 / 99.7%) or grade preference
Quantity and planned reorder
The more details you provide, the faster we can quote.
*We respond within 24 hours. All inquiries are confidential.
