Heating device for high temperature X-ray powder diffraction studies undercontrolled water vapour pressure (0-1000 mbar) and gas temperature (20-200degrees C)

In this paper we present a high temperature hearing device, working under d efined environmental conditions, for a Siemens D500 Bragg-Brentano powder d iffractometer. The powder sample is prepared in a flat mould on a metal blo ck consisting either of copper or of platinum depending on the temperature range selected for investigations. Although the heating cell can be used se parately under ambient conditions up to sample temperatures of 1000 degrees C, it is possible to work under defined environmental conditions in the te mperature range between 10 and 200 degrees C and up to a water vapour press ure of 1000 mbar. For that purpose a special cover fur the in situ control of temperature and water vapour pressure has been constructed. It is import ant to note that the three sample conditions (sample temperature, gas tempe rature. and gas humidity) can be adjusted separately by the user. Current s tudies have shown that the described X-ray heating device is a powerful too l to study dehydration reactions in the frame of fundamental research as we ll as to understand industrially relevant processes concerning dehydration reactions and their mechanisms. (C) 2000 International Centre for Diffracti on Data. [S0885-7156(99)00303-6].