FORM 07
Ceramic Insulators
Insulating bodies, spacers and supports for equipment that runs hot and live at the same time.
View ceramic insulatorsDUTY 03
Ceramic insulators, standoffs and insulating tubes
Insulation is easy until the part also has to be hot, or loaded, or outdoors. Ceramic keeps insulating where polymer has already tracking-failed.
Polymer insulators are cheaper and easier to fix, so they are used until the duty makes them fail: surface tracking under contamination, creep under a hot terminal, or outgassing in vacuum. Once a part has to insulate and also sit in a furnace, hold a load or live in a vacuum chamber, the material list shortens quickly.
Alumina is the usual starting point because it insulates well and holds its shape hot. Silicon nitride is chosen when the part is also a structural element that sees thermal cycles. The specification work is mostly about creepage path, the metal interface, and how the part is cleaned — not about the grade alone.
Why ceramic
What changes when the part is ceramic
Insulation that survives heat
Alumina keeps its dielectric behaviour and its shape where polymer creeps, chars or tracks.
Dimensionally stable under load
A ceramic standoff does not relax over years of compression the way a thermoplastic does.
Clean in vacuum
Dense ceramic does not outgas in the way polymer and some composites do, which is why it appears in vacuum and plasma hardware.
Material fit
Which system suits this duty
Ratings follow the comparison published for the four systems. The grade is confirmed against the duty at quotation.
| Material | Choose it when |
|---|---|
| Alumina | The default for insulator bodies, terminal blocks and standoffs; the widest range of shapes. |
| Silicon nitride | Insulating parts that are also structural and see thermal cycling. |
| Zirconia | Insulation with wear or impact on the same part, such as a locating collar. |
| Silicon carbide | Conductive or semi-conductive duty, and where erosion dominates over insulation. |
Part forms
Forms supplied for this duty
Each form page carries the dimensional call-outs and ordering route for that shape.
FORM 01
Ceramic Tubes
Straight and stepped tubes for high-temperature process lines, sensor protection and electrical isolation.
View ceramic tubesFORM 03
Ceramic Rods
Solid rods and ground pins for structural, insulating and wear duty in tight assemblies.
View ceramic rodsFORM 04
Ceramic Plates
Flat plates and substrates where flatness, insulation and wear resistance decide the part.
View ceramic platesFORM 12
Ceramic Structural Parts
Blocks, brackets and spacers that locate, support or isolate inside equipment.
View ceramic structural partsOn the drawing
What this duty needs pinned down
- The voltage and the creepage path the design must hold, including altitude or contamination assumptions.
- What the metal hardware is, and whether the joint is cemented, clamped or threaded.
- The temperature at the terminal, not the ambient — this is where polymer designs usually fail.
- Whether the part is a barrier, a spacer or a structural support, because that decides the wall section.
Inspection
What gets checked
- Bore and outside diameter concentricity on tubes and standoffs, which sets the creepage distance.
- Chipping at the ends and at hole edges, where tracking starts.
- Flatness of mounting faces on terminal blocks and plates.
Inspection points are agreed at quotation and recorded, so the first article and the tenth are judged the same way.
Questions
Asked about this duty
Can ceramic replace a polymer insulator directly?
The envelope can usually be matched, but the fixing has to change. Ceramic does not compress like polymer, so a clamped joint needs a compliant element, and a threaded joint needs a different insert strategy. Both are normally resolved on the drawing rather than on the shop floor.
What decides the creepage path?
Voltage, contamination class and altitude together. Adding ribs increases the path but also increases the moulding or machining cost, so the rib profile is normally set from the pollution severity rather than copied from an existing part.
Is alumina suitable in vacuum?
Dense alumina is used in vacuum and plasma hardware, but the grade matters: porosity and the binder system decide how much the part outgasses. For critical vacuum duty the grade is chosen for that, and the cleaning route is agreed before production.
Continue
Other pages in this catalogue
The same catalogue, filed by material and by shape.