Comparison of high purity fine grain graphites from different suppliers with regard to physical, mechanical and thermal properties : Final report

摘要

By order of The Jet Joint Undertaking, The European Atomic Energy Community, eight high purity fine grain graphites and one carbon fibre composite were investigated with regard to a number of properties as far as to their thermal shock behaviour. The following properties were determined: - Apparent density - Total and open porosity - Electrical resistivity between room temperature and 1000°C - Thermal conductivity between100°C and 1000°c - Linear thermal expansion between room temperature and 1000 °C - Dynamic Young's modulus - Bending strength and fracture deflexion. A number of impurities- including sulfur- were determined. Multi-element analytical methods, such as spark source mass spectrometry and optical atom emission spectrometry with excitation in an inductively coupled plasma, were used rendering the simultanious detection of about 45 elements. Sulfur was detected by the classical method of burning to S0$_{2}$ and application of infrared. Four series of thermal shock and erosion experiments were carried out on all graphites and the carbon fibre composite. For this purpose, graphite samples were exposed to a defocussed electron beam of different power densities and pulse durations. The erosion behaviour of the particular materials differred significantly.