LaCrO thermal expansion coefficients

Ca-doped LaCrOs, for example. The thermal expansion coefficients of the components must be as close to one another as possible to minimize thermal stresses which could lead to cracking and thermal failure. Optical fleximetry is a valuable tool for studying these systems. Details can be found at www.expertsystemsolutions.com. 

Numerous studies have investigated coating the interconnect with a dense protective oxide layer to reduce surface oxidation and chromium contamination of other key components [124, 125]. Perovskite materials such as LaCrOs typically used for higher temperature ceramic interconnects are ideal as their conductivity and thermal expansion coefficient can be tailored through doping to ensure compatibility and optimise performance. 

Thermal expansion coefficient is another issue. The thermal expansion coefficient of non-doped LaCrOs is small compared with YSZ. To match the thermal expansion coefficient, there are two ways one is the heavy aUcaline earth doping up to 30 mol%, the other being addition of alumina to YSZ to reduce the effective thermal expansion coefficient of a mixture of YSZ and AI2O3 [35]. 

Fig. 15.7 (a) Thermal expansion behaviors of some doped LaCrOs in air and in the H2 atmosphere in comparison with 8YSZ electrolyte, (b) Thermal expansion coefficients of Lao.8Sro.2Cro.9 xTio.iVxOs in the temperature range SO -1000 C in air or in the H2 atmosphere. (Reproduced by permission of The Electrochemical Society [35])... 

Concerning interconnect materials, pure LaCrOs has an averaged thermal expansion coefficient = (8.6 to 9.4) X 10 (from room temperature to 1000 °C in air) which is signifi-... 

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