La 2 (Zr 0.7 Ce 0.3 ) 2 O 7 (LZ7C3) ceramic was prepared by solid state reaction method at 1400 °C for 12h using La 2 O 3 , ZrO 2 , and CeO 2 as starting reactants. The phase composition and microstructures were studied by XRD and SEM technology. The thermal conductivity and linear thermal expansion coefficient were investigated by laser-flash method and pushing-rod method respectively. XRD results revealed that LZ7C3 is a mixture of pyrochlore and fluorite, and the pyrochlore is the main phase which is a small solid solution of La 2 Ce 2 O 7 (LC) in La 2 Zr 2 O 7 (LZ). The thermal conductivity of LZ7C3 decrease gradually with the increase in temperature until 1200°C, and the value is 0.79 W⋅m -1 ⋅K -1 , which is almost 50% lower than that of LZ. The linear thermal expansion coefficient which is 11.6 × 10 -6 K -1 at 1200°C is larger than that of LZ. These results show that LZ7C3 ceramic material can be explored as a novel prospective candidate material for use in new thermal barrier coating systems in the future.

Thermoelectric (TE) power generation from waste heat is recently attracted much attention as one of energy-saving technologies. In this paper, Co-doped n-type iron silicide semiconductor was plasma sprayed under various spray conditions to find the optimum spray-forming conditions. Then Co-doped iron silicide TE device with thickness ranging from 3 to 5 mm and the area of over 100 cm square was produced in the form of a plate or on tube. The paper examines the microstructure and evaluates thermal and electric properties. Paper includes a German-language abstract.