Effect of Y2O3 addition on the oxidation resistance of TiN/Ni composites applied for intermediate temperature solid oxide fuel cell interconnects

摘要

TiN/Ni Composites with high electrical conductivity and suitable thermal expansion coefficient have become potential materials for intermediate temperature solid oxide fuel cells interconnects (IT-SOFCs). The interconnect study is very broad in the current form, which is crucially important to increase fuel- cells power efficiency. In order to study the effect of Y2O3 addition on the oxidation resistance of TiN/Ni composites, composites with low Y2O3 content are fabricated by spark plasma sintering. The results show that by adding minor Y2O3, the average size of TiN particles increases from 1.65 mu m to 2.92 mu m. In addition, adding Y2O3 to the composite can reduce the mass gain (800 degrees C/120 h oxidation) from 4.46 mg.cm(-2) to 2.97 mg.cm(-2), which is a result of that Y2O3 promoted the formation of relatively dense NiO and inhibits the formation of loose rutile TiO2. Compared with TiN/Ni composites without Y2O3 , the thermal expansion coefficient of Y2O3-containing composites is reduced from 12.4 x 10(-6) k(-1) to 11.9 x 10(-6) k(-1), and the diffusion depth of O is brought down from 98 mu m to 63 mu m. Meanwhile, composites with Y2O3 exhibits excellent electrical conductivity (1.34 x 10(4) S.cm(-1)), and high flexural strength (716 +/- 14 MPa) after 800 degrees C/120 h oxidation. Therefore, Y2O3 can effectively change the composition and microstructure of the oxide scale and optimize the oxidation resistance of composites.