We use spray coating of e.g. SiO2, Si3N4 and SiC to functionalize crucibles and other furnace parts in order to reduce harmful defects and impurities and to increase the lifetime of the furnace parts. For Cz silica crucibles we have a qualified vacuum bake out test procedure in order to investigate bubble behavior and cristobalite formation. Another focus is on ultra-high-temperature and chemical resistant protective TaC coatings on graphite and other materials. We develop this novel patented technology for applications in semiconductor industry, especially for SiC PVT crystal growth and epitaxy, but we address also space and aviation applications.