How Technetics and Orion Engineered a Repeatable PTFE Coating Process for Complex Rocket Seals
In aerospace propulsion systems, seals are silent workhorses. Hidden inside rocket and jet engines, they maintain pressure differentials, minimize leakage, and perform reliably amid extreme heat, vibration, and in some applications, extremely low cryogenic temperatures. Their performance is foundational to aircraft safety, efficiency, and mission readiness.
Each rocket engine contains dozens of precision seals. Across global aerospace fleets, from advanced space and defense platforms to commercial widebody aircraft, this translates into tens of thousands of seals operating continuously under demanding conditions.
Procurement contracts reflect how critical seals for aerospace are. The Defense Logistics Agency recently purchased a single line of 20 labyrinth seals for more than $127,000, while the Pentagon maintains multimillion-dollar standing contracts for specific seal classes. These components are small, but their role is massive.
Tier 1 aerospace supplier Technetics Group, known for precision-engineered sealing solutions, had a unique and challenging opportunity for PTFE (polytetrafluoroethylene) coated seals to be used in a rocket engine. For Technetics, the challenge was how to apply the PTFE coating consistently across an exceptionally complex geometry.
The global manufacturer needed a repeatable coating process, not just a one-off success. The coating demanded perfection.
Design Complexity Meets Performance Demands
The seals were designed for advanced rocket engine propulsion applications, where reliability is non-negotiable. Each part featured a crescent-shaped groove machined into a narrow, half-inch interior diameter. Every surface, including the recessed groove, required complete, uniform coverage with a high-performance PTFE-based coating.
“This is a very difficult seal to PTFE coat and must adhere to strict NASA requirements,” said Scott Coburn, Technetics quality assurance manager.
PTFE-coated seals are widely used in aerospace, particularly in cryogenic environments, because of PTFE’s unique material properties. It maintains low friction and dimensional stability at extremely low temperatures, with performance capabilities extending to -400°F.
These characteristics make PTFE coatings especially well-suited for liquid oxygen, liquid hydrogen, and other cryogenic propulsion systems where seals must perform reliably during rapid thermal cycling and prolonged exposure to extreme cold. In contrast, plated seals are typically reserved for higher-temperature applications where different wear and thermal characteristics are required.
In this case, the performance requirements were exacting and unforgiving:
- Uniform Coverage: PTFE coating had to reach every micron of the seal without gaps or buildup.
- Coating Thickness: Coating too thin wouldn’t protect as needed; too thick and the seal wouldn’t fit properly.
- Coating Tolerance: Uniform coating on the entire part, with micron allowed variance, consistent from part to part.
- Adhesion Strength: Any delamination could cause catastrophic seal failure in service.
Traditional spray coating methods struggled to reach uniformly into the recessed interior groove. Dip spin coating processes introduced variability in thickness, particularly along edges and transitions.
The challenge was determined to be the interaction between geometry, tolerances, and application method. They needed to find a way to achieve uniformity throughout the seal, including the difficult contours of the inside diameter (ID), on every coated part.
Seeking a partner with functional coating expertise, technical depth and production discipline, Technetics reached out to Orion Industries, an AS9100D-certified functional coating applicator.
Continue reading this article on SME Advanced Manufacturing, authored by Scott Yoder, Orion’s Regional Sales Manager and Technical Consultant.
Learn more about Orion’s aerospace and defense coating services and how we can help to improve the performance or your product, part or component.
Contact us to discuss your project with our technical consultants.