Resistive heater in high pressure and high temperature apparatus

Recently, numerous efforts have been made to significantly extend the pressure and temperature range as well as sample volume in high pressure and high temperature (HP/HT) experiments, especially with the aim of opening up the research areas of materials science and geoscience. HP/HT apparatus thus becomes an important experimental tool in these fields. There are various HP/HT apparatus which could achieve a wide range of pressures and temperatures with different sample sizes. Normally, relatively large volume samples can be obtained by multi-anvil type and toroidal type HP/HT apparatus. During the HP/HT experiments, the setup of the assembly will affect the results strongly. The assembly usually contains furnace (resistive heater and insulator), pressure medium and thermocouple etc. Among all these components, the furnace may be the most important part. The temperature inside the HP/HT cell increases when the electric current flows through the resistive heater. Hence the properties of the resistive heater are the concern of researchers. The most widely used materials for the resistive heater are graphite, high melting point metals, LaCrO3 and some composites. However, all of them have some drawbacks. To overcome the weakness of the commonly used technologies, new polymer-precursor-derived composites (PPDCs) for resistive heaters in HP/HT apparatus will be investigated; polymer-derived ceramics (PDCs) processing is used due to the possibility of low fabrication temperature and easy manufacturing. The processes and properties related to the preparation of these novel heaters and HP/HT runs will be discussed.