MSL compatible isothermal furnace insert for high temperature shear-cell diusion experiments

Abstract

For long-time diusion experiments shear-cell techniques oer more favourable terms than the traditional long capillary techniques. Here, we present a further developed shear-cell that enables the measurement of diusion coecients up to temperatures of 1600 C. Hence, diusion experiments can be carried out at temperatures not accessible until now by conventional capillary or shear-cell techniques. The modied shear-cell, which can contain up to six samples of a total length of 90mm and a diameter of 1.5 mm, is built of 30 shear discs of 3mm thickness each. It is operated in an isothermal furnace insert which can be accommodated in the Materials Science Laboratory of the International Space Station. This provides the opportunity that the shear-cell can be applied to microgravity and to ground-based experiments, respectively. The heater insert with an overall length of 518mm and a diameter of 210mm consists of four heating zones with a total power of 3.5 kW. Temperature homogeneity along the graphite sample compartment is better than 2K at 1600 C. Details of the new design are discussed and results of rst successfully performed heating and shearing cycles are presented