FORM 05
Ceramic Rings
Ground rings and sealing elements for assemblies that must hold a bore or a face at temperature.
View ceramic ringsDUTY 01
Ceramic parts for pumps, valves and fluid handling
Where a metal seat wears oval, a ceramic one holds its form. These are the parts that sit in the flow path and take the wear so the pump body does not.
A pump or valve usually fails at the same three places: the seat, the plunger and the bush. Metal there wears unevenly under abrasive slurry, galls against itself when the lubricant is washed away, and creeps when the line runs hot. The result is a slow loss of shut-off rather than a sudden break, which is why it is often tolerated far too long.
Technical ceramics change the failure mode. Alumina and zirconia hold a lapped face far longer under abrasive flow, silicon carbide resists chemical attack as well as wear, and silicon nitride takes repeated mechanical load without chipping at the edge. What changes is not only life, but the predictability of the shut-off.
Why ceramic
What changes when the part is ceramic
A face that stays flat
A lapped ceramic seat keeps its geometry under abrasive flow, so shut-off stays positive instead of degrading into a slow weep.
No galling against itself
Ceramic against ceramic does not cold-weld when the process fluid strips the lubricant, which is the usual cause of a seized metal trim.
Wear is the design variable
Grade and surface finish can be chosen for the duty — abrasive slurry, clean chemistry or clean water — rather than settling for one metal for every line.
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 |
|---|---|
| Zirconia | Abrasive duty with impact: seats, plungers and bushes that see slurry or intermittent load. |
| Silicon carbide | Wear combined with chemical attack, and the highest sliding speeds. |
| Alumina | Clean fluids, moderate abrasion, and where cost per part governs the choice. |
| Silicon nitride | Repeated mechanical load and thermal cycling on the same part. |
Part forms
Forms supplied for this duty
Each form page carries the dimensional call-outs and ordering route for that shape.
FORM 08
Ceramic Wear Parts
Liners, guides, bushes and contact parts that outlast metal where surfaces abrade or gall.
View ceramic wear partsFORM 10
Ceramic Balls
Spheres for valve, bearing and milling duty, where diameter and roundness both have to be held.
View ceramic ballsFORM 11
Ceramic Discs
Machined discs with concentric features for seats, wear faces and rotating duty.
View ceramic discsFORM 03
Ceramic Rods
Solid rods and ground pins for structural, insulating and wear duty in tight assemblies.
View ceramic rodsOn the drawing
What this duty needs pinned down
- The fluid: composition, solids content, particle size if abrasive, and temperature.
- Which face does the sealing — a lapped flat, a spherical seat, or a bore.
- Whether the part moves against ceramic or against metal, since the counterface decides the finish.
- The pressure and the cycle count, so the wall section is set by the load rather than by habit.
Inspection
What gets checked
- Sealing faces checked for flatness and for edge chipping, which is where leakage starts.
- Bore and outside diameter measured at the datum the drawing names, not at the ends.
- Concentricity of bore to outside diameter on bushes and rings.
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 a ceramic seat simply replace the metal one?
Usually the geometry can, but the counterface cannot be ignored. A ceramic seat running against a metal plug will wear the plug; both faces are normally changed together, and the housing may need a different seat retention because ceramics do not yield to an interference fit.
Which grade for slurry duty?
Zirconia where the slurry carries solids and the part also sees impact; silicon carbide where the fluid is also chemically aggressive. Alumina is the economical choice when the solids are fine and the load is steady. The grade is confirmed against the duty at quotation.
Does a ceramic plunger need a different surface finish?
Yes. The sliding band needs a finer finish than the rest of the part, and the transition has to be specified on the drawing — a uniform call-out over the whole length either costs money or leaves the sealing band too rough.
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Other pages in this catalogue
The same catalogue, filed by material and by shape.