Heat development in corrosive environments can place a severe strain on technical components. Ceramics present a solution. This material is particularly resilient towards wear, heat and pressure. It also exhibits excellent electrical insulation properties. Schunk Carbon Technology is a world leader in the development, manufacture and application of carbon and ceramic solutions. Schunk uses innovative production methods for material systems based on ceramic fibers. This significantly increases the product life of the system components and tools for our customers. The oxide fiber-reinforced oxide ceramics offers all the advantages of conventional ceramics but exhibits much higher impact resistance and survives even the most rapid of temperature changes.
Temperatures of over 1,000 degrees combined with extreme environmental conditions are not uncommon. They occur in aviation and space travel, for instance in aircraft and stationary gas turbines, chemical engineering as well as in burner and flame tubes. Heat treatment processing serves as another example. Furnace doors, flaps and transport components as well as fixture systems are subjected to extreme heat and often thermal shock. Here, oxide ceramic composite materials Ox/Ox or O-CMC (Oxide Ceramic Matrix Composite) for short, are used. These materials withstand the most extreme conditions thanks to their material design consisting of oxide ceramic high-performance fiber roving and nanoporous matrix. Ox/Ox stands up to thermomechanical stress in severely corrosive or oxidizing atmospheres. Up to now, the industrial use of these materials was, for the most part, not feasible as the required production technologies had not been developed.
High-Tech with experience
Schunk Carbon Technology has managed to develop new manufacturing approaches and can now supply the market with cost-effective Ox/Ox products. This was made possible by its know-how and years of experience in collaborating with leading international research institutes in this field. Schunk manufactures oxide fiber-reinforced composites that have a considerably longer lifespan than materials previously used, owing to innovative and industrially scalable production techniques. Because oxide ceramic composite materials are extremely resistant to heat and thermal shock, neither rapid heating nor cooling presents a problem. This not only shortens the process time, but also allows for improved material properties for the product through the heat treatment. Oxide ceramic composite materials are, for example, especially well-proven in fixture systems for the heat treatment of metal components. Here, Ox/Ox has one more advantage when compared with traditional materials: the customers’ products are not contaminated through material diffusion with the carbon-based carrier materials.
Versatile, resilient, cost-efficient
As a rule, the manufactured composite materials consist of aluminum oxide fibers surrounded by a ceramic matrix of aluminum oxide and zirconium oxide. Ceramic slurry is the first step of the production chain as in case of any ceramic product. The powder composition is chosen in such a way so that the parts are particularly strong after sintering: a nail could easily be driven through a plate made of Ox/Ox without any risk of the part as a whole failing.
Schunk offers a wide range of manufacturing techniques. This allows us to fulfill unusual customer requirements. If parts with complicated shapes are needed, for instance, then we would favor processing the material using an autoclave and starting out with oxide ceramic prepegs (pre-impregnated fiber-textile material). Using winding technology, we manufacture rotationally-symmetric geometries. The broad spectrum of production and engineering approaches makes it possible to manufacture components for applications that have thus far not been feasible, while at the same time offering cost efficiency. Today, Schunk is capable of producing plates with a size of up to one square meter, wound tubes with a diameters of over one meter on industrial scales as well as 3-D shaped parts using lamination and vacuum technology.