Elektrische Heizbarkeit und Mikrostrukturierbarkeit einer Mischkeramik aus Aluminiumoxid und Titannitrid

The Al_2O_3/TiN-System was investigated in order to prove both its feasibility as material for heating elements and its capability for generating microscaled patterns. Powders were mixed in different ratios from 8% to 50% TiN by volume and subsequently dry-pressed. Bodies exceeding 98% th.d. were achieved by sintering at 1750 C in a nitrogen atmosphere. All bodies that contain at least 18% TiN exhibit metal-like conductivity. The change of resistivity with the TiN content is best described by the percolation theory for close packings of spheres. Actually, resistivity could be adjusted between 50 #mu##OMEGA#cm and 500 m#OMEGA#cm. Using at least two different mixtures of alumina and titanium nitride allows the fabrication of heating elements with cold ends and a hot region. Therefore the ends must contain more TiN (e.g. 40%) than the heated region (e.g. 20%). Lead wires can be mechanically attached without using a solder. These heating elements can be operated in air at a temperature of 600 C for several weeks. Oxidation of TiN is prevented by applying an alumina coating on the heatable region. (orig.)68 refs.Available from TIB Hannover: ZA 5141(6173) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman