In order for ceramic to be hard and dense, they must be "sintered", or fired to high temperatures for prolonged periods of time in gas or electric kilns. Typical firing temperatures for alumina, mullite, and zirconia reach 2850 °F - 3100 °F. Typical firing cycles can range from 12 - 120 hours depending upon the kiln type and product. Ceramics shrink approximately 20% during the sintering process. Non-uniform shrinkage as a result of standard forming and machining processes can cause deformation of the ceramic. Our experience and knowledge of ceramic processing allows us to utilize specific machining and firing methods to help limit these effects. See our Kiln Room here.
After Firing, ceramic materials often undergo several additional operations:
Grinding and Cleaning - Post firing machining may be required to achieve tight tolerances, and surface finishes. Most fired alumina ceramics can become dirty through handling, machining or inspecting. These oils, dirts and metal marks can be removed using a variety of techniques.
Coating / Glazing - One of the reasons that parts are glazed is to make it easy to remove unwanted residue. For instance, spark plugs are glazed to reduce areas of potential arcing in high voltage environments.
Metalizing & Plating - We produce thick film metalization inks that utilize a Moly-Manganese (MoMn) refractory formulation designed for oxide ceramic bodies to provide one of the industry's strongest bond strengths.