Research on Heat Storage and Heat Transfer Performance and Thermal Stability of Porous Pt Electrodes

The variations of the heat storage and heat transfer properties, such as heat capacity, thermal conductivity, and thermal storage stability, with temperature, time and grain radius of Pt electrode for oxygen sensor are studied by using the theory and method of solid-state physics, and the effect of anharmonic vibration of atoms on the heat storage and heat transfer properties and the thermal stability is discussed. The results show that the heat capacity of Pt electrode increases with temperature, increasing at first then tending to be constant, and decreases with grain radius and time increasing. The thermal storage stability coefficient of the Pt electrode material increases sharply at first and then decreases rapidly with temperature increasing, and finally tends to be constant. When the temperature is about 60 K, the thermal storage stability is the worst. The thermal conductivity of Pt electrode material decreases sharply at first and then tends to be constant with temperature increasing, increases with grain radius increasing, and decreases with time increasing. The contribution of the surface layer to thermal conductivity decreases sharply at first and then tends to be zero with temperature increasing. The anharmonic effect of the electrode material makes the heat capacity decrease, while makes the thermal storage stability coefficient and thermal conductivity increase. The results in this paper are basically consistent with that in other literatures, and the conclusions can provide theoretical guidance for the stability of solid electrolyte oxygen sensors.