Abstract: We are introducing a novel, black silica-composite material. The black appearance of HBQ is achieved by embedding elemental Silicon particles in a densely sintered, pure silica matrix (>99.9%). Material properties, such as low thermal conductivity, thermal shock resistance, low coefficient of thermal expansion and chemical inertness, are governed by the silica matrix. The temperature dependent high emissivity of HBQ results from the indirect band-gap of the incorporated elemental Silicon. The absence of carbon in the material yields a high resistance against oxidizing and reducing atmosphere at temperatures up to as high as 13000C. Combined with the availability in a wide dimensional range and the ease of machining, HBQ is suitable for a wide field of applications and is already in use where emissivity, purity and thermal stability are essential.
Authors: Frank Wessely, Dennis Braeuhaus, Gerrit Scheich, and Nils Christian Nielsen
Keywords: Black Quartz, High Purity, High Emissivity, Low Thermal Conductivity, Low Thermal Expansion, Insulator, High Temperature, Chemical Inertness, Composite Material