Firing Methods
CoorsTek has hundreds of production kilns throughout its facilities worldwide. Firing is yet another way that ceramics can be customized to fit the exacting requirements for your design. There are different types of kilns suitable for different material formulations and requirements such as production volume, density, and cost, allowing our engineers to select the most advantageous techniques for optimal end results.
CONTINUOUS KILNS
Continuous kilns are the most economical firing method and is generally for large volume production runs. These kilns run train-like cars on a track through a continuous chamber (or tunnel), sintering the product for long periods of time as they move through.
PERIODIC KILNS
Periodic kilns are better for smaller volume productions. Products fired in these kilns remain stationary throughout the process, and the kiln is fired and heated with each production batch. These kilns are advantageous for firing several different products. There are several different types of periodic kilns, including, hot presses, hot isostatic presses, and atmospheric or vacuum furnaces.
PRESSURE ASSISTED FORMING AND FIRING:
Hot Pressing and Hot Isostatic Pressing
Certain material compositions are too refractory (resistant to heat) for firing with only high temperatures. These materials can be fired using pressure assisted options, where both temperature and pressure are applied at the same time. These methods ensure refractory materials maintain the intended shape and material density during the firing process. We have two pressure assisted firing options:
- HOT PRESS KILNS
Hot press kilns apply pressure in one direction during the firing process and is used for any material composition requiring pressure assistance for densification and is amenable to the geometric requirements. The process feeds the dry powder into a graphite mold. Heat is then applied while the punch applies the axial pressure. Multiple parts can be pressed simultaneously.
- HOT ISOSTATIC PRESSING (HIP)
Hot isostatic pressing applies force in every direction through a pressurized gas medium at temperature. Ceramic powder or a pre-sintered ceramic body are inserted into a steel vessel filled with an inert gas such as argon, or in certain cases, nitrogen. A combination of heat and pressure are applied within the chamber to press the part from all directions.
ATMOSPHERIC AND VACUUM KILNS
Non-oxide ceramics such as nitrides and carbides require specialized firing environments, requiring an atmospheric or vacuum furnaces to provide a stable environment for sintering. Oxide materials do not react catastrophically when fired in air. Non-oxides, however, must be fired in a vacuum or inert environments to prevent a reaction and forming another composition. Vacuum and atmospheric furnaces prevent the atmosphere from interacting with and changing the properties of the materials during the firing process.
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.
