Thermodynamics and transport of gaseous iridium oxides in multi-hundred-watt thermoelectric generators

Abstract

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Magnetic Behaviour of the $Bi_{2-y} Sr_y Ir_2 O_7$ Pyrochlore Solid Solution

“…The Ir 4+ atomic fractions reported in this work agree well with the oxygen occupation factors from previous Rietveld refinements results [13]. The difference between the stoichiometric Sr value, y, and the Ir 5+ content of samples to preserve electroneutrality, can be attributed to the oxygen deficiencies of samples [19].…”

“…Considering the oxygen occupation values obtained from the Rietveld analysis [13], it is possible to think that Schottky reactions could happen, however the corresponding bismuth or iridium oxides were not found in the diffraction patterns as products of such reaction. It should be pointed out that the prolonged time of the solid-state reaction could lead to evaporation and disproportionation of the iridium-oxide, releasing oxygen [19]. On the basis of the experimental results, it is clear that reaction 3 is being preferred but is difficult to accurately determine the oxygen content of samples.…”

Iridium‐Based Selective Emitters for Thermophotovoltaic Applications

“…Hightemperature experiments on bulk Ir at different pressures and temperature ranges between 600-2000 °C, reveal different oxidation processes of Ir. [83][84][85][86][87][88][89] It was reported that at 1 bar pressure and above 600 °C, the solid oxide IrO 2 is formed and it is stable up to 1100 °C. [88] On increasing the temperature further, IrO 2 transforms into IrO 3 , which exists only in a gaseous state, therefore it sublimates rapidly, leaving behind a fresh metal surface.…”