Finishing Methods
To meet tight tolerances and achieve requirements for precision applications, ceramic finishing is often necessary. CoorsTek offers a multitude of finishing and coating options including several methods of shaping, coating, assembly, and other specialized methods. Each component CoorsTek manufactures is customized to customer specifications.
Finishing
MACHINING
Some geometric features maybe be logistically difficult to create during the forming process, often requiring additional shaping after firing is completed. This can be accomplished through grinding, laser cutting, lapping, tumbling, and polishing.
Grinding is an excellent method for achieving precise tolerances. To accomplish this, we use 5-axis CNC routers, 5-axis vertical machining, 5-axis high speed grinding machines, milling machines, and lathes.
Free abrasive machining processes are essential for creating exacting flatness on components. We provide secondary diamond head lapping and polishing down to surface flatnesses of <2-3 helium light bands (<0.6-0.9 microns)
Laser and waterjet machining create complex cut-outs and precise edges for substrates and other applications.
CoorsTek has over 1,000 shaping centers available throughout the world to serve its customers.
ASSEMBLY: BRAZING, BONDING, AND OTHERS
A common method for assembly is brazing and bonding.
Brazing bonds ceramic to metal by creating a thin, uniform joint between two components. Assembly can also be achieved with specialized adhesives and epoxies, as well as chemical bonding, soldering, and mechanical assemblies such as screws and bolts.
Interference fitting is used for ceramic-metal assemblies where the ceramic is housed by a larger metallic component and commonly done through shrink-fitting. The thermal expansion mismatch between the metal and ceramic materials creates a clearance for assembly at an elevated temperature. When cooled, this creates the appropriate interference between the two materials.
Some technical ceramic geometries are too complex for conventional forming methods but can be created by co-sintering two or more ceramic components together. Doing this makes it possible to create a monolithic piece with a hermetic seal between the ceramics, making nearly impossible to distinguish between the separate ceramic parts and the bond.
Coatings
Ceramic coatings are useful for numerous applications, generally providing enhanced or specialized material properties such as increased electrical insulation, corrosion resistance, or increased purity. In addition to the coatings listed below, we should also consider chemical vapor deposition (CVD). However, CVD is both a specialized forming and coating process. You can learn more about CVD here.
METALLIZING
Metallizing is a secondary process that applies a thin layer of refractory metal paste to the ceramic surface. Components are then fired to create a strong bond between the metal and ceramic. The refractory layer is plated with metallic compositions suitable for brazing.
Metallization is used for antennas, x-ray tubes, and electronic circuit pathways on high-purity substrates.
GLAZING
Glazing is used to put a glass overlay onto a ceramic component. This is often used to achieve a high polish finish resistive to dust and dirt.
This finishing method is used in outdoor industrialized applications such as electrical insulator components.
PLASMA SPRAYING
Plasma spray coatings are used for semiconductor applications to provide high corrosion resistance. These coatings are applied using a dry powder gun to spray the ceramic powder, through an ionized gas environment at very high temperatures. The powder melts and hits the surface of the components as a molten particle, instantly solidifying.
RESISTIVE COATINGS
Resistive coatings manipulate the electrical properties of a component without compromising strength or other mechanical properties. They can also be tailored to control the dissipative or conductive properties. Applications using resistive coatings are X-ray/XRF/XRD where electrostatic discharge can threaten the integrity of the component.
Related Information
Looking to further explore the properties of technical ceramics or learn more about component design and manufacturing. Download our award-winning ebooks:
- A View to a Kiln explores our methods and processes used to manufacture technical ceramic components used in many industry applications. Our engineers take ideas from concept to firing and finishing.
- Ceramics: The Powerhouse of Advanced Materials explores the various properties of technical ceramics – mechanical, thermal, electrical, and chemical – and how they outperform metals and polymers in a myriad of industries.
