their carriages as an anti-graffiti coating. Beyond that, organopolysilazanes can be applied as high temperature coatings or anti-corrosion varnishes. The inorganic perhydropolysilazane can be used in a similar way. Curing in air yields a carbon-free amorphous coating of SiOx. Compared to organopolysilazane-derived materials, these coatings are less flexible but very smooth and dense. They show excellent barrier properties (against water vapor or oxygen) and a low electrical conductivity. This makes them suitable candidates for different application in electronics or solar industry. Polysilazanes can be used as or in combination with synthetic resins. First experiments on specially treated components have shown that thermally cured materials can withstand temperatures of 400 - 600 °C. Most plastics are not applicable in this temperature range. The resins will be used for the fabrication of non-combustible fiber-reinforced composites. Polysilazanes are suitable precursors for ceramic materials. Since most ceramic materials are produced by powder processing and sintering, near net shape forming is very difficult for complex components. With the aid of organic binders added to ceramic powders, injection molding or other casting techniques are possible, but removal of the organics (“debinding”) is expensive and results in fragile “white bodies” which are difficult to handle and shrink significantly during sintering. Pre-ceramic polymers can replace these organic binders. After compounding, casting and curing, the thermoset material can be pyrolyzed in one step to give a ceramic component in high yield. However, this application is still in its infancy in the civilian area. Physical and chemical properties of pre-ceramic polymers can be varied in a wide range by chemical modifications. This is crucial for the production of ceramic fibers, an important topic both at universities and in industrial research. Silicon carbide fibers made from polycarbosilanes were the first to be used for reinforcement of ceramic matrix composites. The production of silicon nitride fibers from perhydropolysilazane was described by Tonen Corp. at the end of the 1980s. Dow Corning modified the HPZ polymer as a precursor for SiCN fibers, and Hoechst AG did successful experiments with VT50. More recently, G. Singh at Kansas State University demonstrated synthesis of boron-modified polysilazane for synthesis of Si(B)CN functionalized carbon nanotubes, which were stable in air up to 1000 C. The PDC-CNT composites are being explored for applications such as damage resistant coatings for high power laser thermal detectors as well as Li-ion battery anodes. References Inorganic polymers Silicon compounds Nitrogen compounds