Name: Custom Alumina Ceramic Ring Slices
Brand: ADCERAX

What an Alumina Ceramic Ring Slice Is

An alumina ceramic ring slice is a flat annular part with a center hole. Its outer diameter, inner diameter and finished thickness work together with the edge profile and contact faces to fit the assembly. ADCERAX reviews the part drawing, the alumina grade and the finished-part inspection requirements for the intended spacing, electrical isolation or support function.

Because the same round ceramic ring can be quoted as a washer, a cut slice or a retaining ring depending on the drawing, state the function and the acceptance criteria with your enquiry. That is what separates a ring slice from a general round ceramic part.

Alumina Ceramic Ring Slice Properties

Property	AD-ALU-950	AD-ALU-960	AD-ALU-990	AD-ALU-995	AD-ALU-997	AD-ALU-999
Al₂O₃ content (wt%)	95	96	99.0	99.5	99.7	99.9
Density (g/cm³)	3.75	3.70	3.80–3.91	3.90–3.92	3.94	3.94
Flexural strength (MPa)	280	300	300–320	320–350	330	315–340
Thermal conductivity (W/(m·K))	18–25	25	24	30–38	35–40	35–42
Temperature selection limit (°C)	1400	1600	1600	1650	1700	1750
Dielectric strength (kV/mm)	10	8.3 AC	10	10	10	10

Alumina Ceramic Ring Slice Specifications

Item	Outer Diameter（ mm)	Inner Diameter(mm）	Height(mm)	Purity（%）
AT-YHL-YMH001	130	109	40	96-99
AT-YHL-YMH002	143	110	40	96-99
AT-YHL-YMH003	148	120	38	96-99
AT-YHL-YMH004	160	140	43	96-99
AT-YHL-YMH005	170	140	40	96-99
AT-YHL-YMH006	178	140	45	96-99
AT-YHL-YMH007	200	169	45	96-99
AT-YHL-YMH008	205	167	45	96-99
AT-YHL-YMH009	220	182	50	96-99
AT-YHL-YMH010	239	201	45	96-99
AT-YHL-YMH011	273	230	40	96-99
AT-YHL-YMH012	273	241	45	96-99
AT-YHL-YMH013	285	250	55	96-99
AT-YHL-YMH014	290	249	45	96-99
AT-YHL-YMH015	296	251	50	96-99
AT-YHL-YMH016	338	306	40	96-99
AT-YHL-YMH017	340	306	50	96-99
AT-YHL-YMH018	353	315	52	96-99
AT-YHL-YMH019	360	322	60	96-99
AT-YHL-YMH020	380	340	55	96-99
AT-YHL-YMH021	395	362	55	96-99
AT-YHL-YMH022	400	352	60	96-99
AT-YHL-YMH023	420	388	60	96-99
AT-YHL-YMH024	440	388	60	96-99
AT-YHL-YMH025	525	486	60	96-99

Download the Product Catalogue

How to Choose an Alumina Ceramic Ring Slice

Select your alumina ring slice in these three steps:

Confirm the geometry.
Specify the OD and ID, finished thickness, contact faces and edge condition. Check how thickness affects seating and how much ceramic remains around the bore and any slots. For a worn part, provide measurements and identify the contact surfaces.
Choose the alumina grade.
Match the grade to the part’s function:1. Electrical insulation: electrical environment and insulation requirements.
2. Axial spacing: clamp load and mating materials.
3. Furnace use: temperature cycles and atmosphere. Choose higher purity when the assembly requires it; purity alone does not determine suitability.
Agree the acceptance requirements.
Identify the critical dimensions, flatness, parallelism, surface roughness and edge condition, then agree how they will be measured. Confirm these requirements before quotation to keep repeat orders consistent.

A sketch showing the part’s function and critical dimensions helps us prepare a suitable quotation faster.

Alumina Compared with Zirconia and Silicon Carbide

Choose the material according to the ring’s main duty:

Alumina — electrical insulation and general use
A common choice for insulating rings, spacers and contact parts. It offers high hardness, stiffness and electrical insulation, with several purity grades to suit different requirements.
Zirconia — impact and edge loading
Higher fracture toughness makes zirconia worth considering when impact or edge chipping is a concern. Its higher density also affects the weight and inertia of rotating parts. Electrical suitability requires a separate grade review.
Silicon carbide — heat transfer and abrasive wear
Consider silicon carbide when heat removal, thermal cycling or abrasive contact drives the design. Check the selected grade’s electrical properties before using it in an insulation application.

If your application combines competing requirements, include both in your enquiry. Final specifications should use grade-specific material data and agreed finished-part inspection criteria.

Alumina Ceramic Ring Slice Packaging

Check the part against the approved drawing.
During receiving inspection, check the finished faces, bore and outer edges to confirm fit. A material grade sheet alone cannot confirm these features.
Specify edge condition and packaging together.
Include acceptable edge conditions and individual transport protection in the order. Thin rings are vulnerable to edge chipping, so packaging should support the agreed edge acceptance criteria.

Alumina Ceramic Ring Slice Applications

A flat alumina ring slice does one of three jobs in an assembly: it isolates, it spaces, or it presents a contact face. Work out which one yours does first — the drawing requirements follow from there.

1. Electrical isolation

The ring holds two conductive parts apart, or keeps a fastening element clear of a live surface.

What to provide: the working and test voltage, AC or DC, the operating temperature, and the environment around the part.

What to check: the creepage and clearance path across the ceramic, the bore and edge condition, and surface cleanliness before assembly.

2. Spacing and alignment

The ring sets a fixed axial gap or acts as a locating surface between two parts.

What to provide: the finished thickness with its tolerance, the face flatness and parallelism, the mating materials, and the clamp load.

What to check: that the faces seat fully instead of rocking, and that the wall width at the bore can carry the clamp force.

3. Contact and support faces

The ring presents a ceramic face where a mating part bears, slides or rests.

What to provide: the contact area, the medium in contact, the service temperature, and the edge detail.

What to check: the face finish and the edge condition against the inspection criteria, because this is where wear and chipping start.

If the ring seals against a mating face rather than isolating or spacing, or if it simply backs a fastener as a general flat washer, the part belongs to a different product form. Compare Alumina Ceramic Seal Rings or Alumina Ceramic Washers.

Alumina Ceramic Ring Slice Usage Instructions

Proper handling, installation, and maintenance of alumina ceramic ring slices ensure long service life, reliable performance, and reduced operational costs.

Before assembly

1. Check the geometry: compare OD, ID, finished thickness, contact faces and edges with the approved drawing and inspection criteria.
2. Prepare the seat: keep mating surfaces clean, dry and free of oil, residue and particles.
3. Handle and align: support the slice with clean lint-free gloves, protect it from drops and sudden impact, and align it with the mating parts.
4. Specified fitting: apply even pressure when the design calls for a press fit; use the specified lubricant and amount when lubrication is part of the approved procedure.
During service

1. Operating duty: follow the approved temperature, pressure, contact-media and assembly conditions.
2. Temperature changes: use the project heating and cooling sequence.
3. Vibration: check the agreed inspection points for changes in wear, cracks or edge condition in high-vibration service.
Cleaning and storage

1. Cleaning: use a soft lint-free cloth and the cleaning agent and method approved for the ceramic and the assembly.
2. Rinse and dry: complete the approved rinsing and drying steps while supporting the part; approved ultrasonic cleaning also needs protected part contact.
3. Storage: keep parts clean, dry and protected from dust in stable conditions; use the original protective packing or separate parts with non-abrasive protection.
When performance changes

1. Edge chipping: review handling, alignment, fitting pressure and edge detail together.
2. Electrical changes: check cleanliness, dryness, visible edge or face defects and the actual assembly electrical conditions before changing the material grade.
3. Seating or leakage changes: review the specified face finish, the compression and the mating-material expansion together.
4. Face wear: review contact area, medium and face condition together rather than raising purity alone.

Alumina Ceramic Ring Slice FAQ

Q: How is electrical acceptance established for an alumina ceramic insulating ring?
A: The alumina grade is a material-selection input, not a rating for the finished part. Establish acceptance on the assembled insulation path: the working and test voltage, the AC or DC condition, the temperature, the environment and the electrode arrangement. Dielectric strength is measured on a test specimen (5 mm or 6.35 mm, depending on grade), so it does not scale to a thin ring by thickness alone. Record the assembly test method and the acceptance criteria with the drawing.
Q: Why specify flatness and parallelism separately from finished thickness?
A: Finished thickness controls the axial stack dimension. Flatness and parallelism describe how the two faces seat and how they relate to each other. A ring can hold its thickness and still rock or gap if the faces are not controlled, which is why the three are called out as separate fields, each with its own inspection method and reference datums.
Q: What load or pressure can an alumina ceramic ring slice carry?
A: There is no single load or pressure rating for the material on its own. For a thin ring the capacity comes from the assembly: the wall width between OD and ID, the support under the contact face, the clamp arrangement, and the edge condition at the bore. Material flexural and compressive strength figures are selection values and do not transfer directly into a working pressure. If the part is clamped or pressurized, describe the load path and the support in the enquiry so the geometry can be reviewed against them.
Q: How should the surface finish be specified on the drawing?
A: State the face condition as a process state first: as-fired, as-cut, ground, fine-ground, lapped or polished. Add an Ra or Rz value only where the assembly needs one, and record it together with the measurement conditions — the evaluation length, the filter and the measurement direction — because an Ra figure on its own does not describe the same surface on every part. The bore and the outer edge follow the same rule.
Q: What information is needed to quote an alumina ceramic ring slice?
A: Start with whatever is available: a drawing or sketch, or photos and measurements of the existing part, plus any known OD, ID, thickness, quantity and part function. The mating component, alumina grade, contact faces, edge condition and operating environment refine the quotation, and critical tolerances or test requirements refine acceptance. Missing fields are listed back rather than assumed. The full staged list is in the RFQ section.