The ideal insulator
Hard felts are dimensionally stable, self-supporting insulation materials in the form of sheets and tubes. All hard felts undergo a multi-stage heat treatment process. In the first process stage, the basic materials (PAN and pitch fibers, as well as viscose) of the blank are carburized. The final heat treatment takes place at temperatures above 2000°C. This so-called graphitization is necessary to convert the structure of the material into a crystalline, graphitic form. In this way, due to their low thermal conductivity and low material thickness, even thin layers of hard felt offer good insulation results.
The structure of a hard-felt sheet consists of several layers of hardened soft felt. Either one or both sides can be laminated with graphite foil or CFC in order to optimize the thermal insulation and the surface protection of the hard felt sheet.
Hard felt is suitable for most high-temperature applications in an inert gas or vacuum environment.
It can be processed using conventional methods, such as cutting, milling, sawing and drilling.