materials
Graphite-filled polyimide
Graphite-filled polyimide is a high-temperature polymer with solid-lubricant graphite. It is the usual family for dry-running bushings and thrust washers when electrical insulation is not the first requirement.
Where this family wins
Bearings, bushings, thrust washers, and dynamic seals that need low friction without a full oil film. DuPont identifies Vespel® SP-21 for that class of duty.
Dominion equivalent grades
Dominion offers graphite-filled polyimide equivalent or alternative grades corresponding to commonly specified Vespel® SP-21, SP-22, SP-211, SCP-5009, SCP-50094, and SCP-5050 materials. Note that “filled” does not always mean graphite-filled — SP-3 is MoS₂-filled and SP-202 is a conductive specialty-filled grade, so those belong to the specialty-filled family.
Questions engineers ask
Short answers
What does graphite-filled polyimide look like?
Typically dark gray or black. Unfilled polyimide is amber or brown. Use the drawing and the spec, not color alone, to identify a grade.
