Papers by Author: Chang Sheng Deng

Abstract: Double-perovskite Sr2Fe1-xScxMoO6- (x = 0, 0.05, 0.1, 0.2, 0.3, 0.4) powders have been synthesized by sol-gel citrate method. Initial powders were calcined in different temperature and atmosphere (air, H2(4vol%)/Ar), then analyzed by using the methods of X-ray, scanning electron microscopy (SEM), as well as thermal analysis. It is found that the formation of perovskite structure is related to the content of Sc, pH value, calcination temperature and sintering atmosphere. Especially, a pure perovskite structure almost completely formed after three hours sintering in atmosphere of H2(4vol%)/Ar. Although the formation of perovskite structure also happened in the air atmosphere, at the same time the SrMoO4 structure formed undesirably as a result of oxidization of Mo.

Abstract: The solid oxide electrolysis cell (SOEC) has been receiving increasing research and attention worldwide due to its potential usage for large-scale production of hydrogen. Tape casting and lamination technique were successfully used to fabricate the NiO-YSZ hydrogen electrode substrate cermets of planar solid oxide electrolysis cell. In this paper the green tape with thickness of 350μm was prepared by tape casting and then the lamination was used to obtain the required thickness for the NiO-YSZ hydrogen electrode-supported electrolyte cermets. The rheological properties of the suspensions with NiO-YSZ and YSZ were studied, respectively. The optimal temperature and pressure of the lamination were determined, and four direction of lamination mode was used according to tape casting direction to obtain symmetrical and even hydrogen electrode-supported electrolyte after co-sintering. Pore-formers were used to increase the porosity of the hydrogen electrode. The green tape was analyzed by TG-DSC analysis, the microstructure was observed by scanning electron microscope. The electrochemical performance of unit cell was measured at 850°C.

Abstract: Pr-doped ceria solid solutions have attracted much attention as promising mixed electronic-ionic conductor and oxygen storage materials. However, little effort has been made to synthesize Pr-doped ceria with one-dimensional nanostructure. In this paper, Pr-doped ceria nanorods were prepared via a facile hydrothermal method using Pr(NO3)3, Ce(NO3)3 and NaOH as raw materials. X-ray diffraction (XRD), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED) indicated that the as-prepared Pr-doped ceria nanorods had a cubic fluorite structure, with the length around 200 ~ 400 nm and the diameters around 10 ~ 18 nm. The effect of alkaline concentration has been systematically studied and the results indicated that higher alkaline concentration was favorable for the formation of nanorods.

Abstract: The dielectric ceramics of CaTiSiO5-CaTiO3 with ZnO and B2O3 as additives were sintered at 950°C. Of the ceramics with a small quantity of 2ZnO-B2O3 as the additive, the density is nearly the same as the one reported, εr= 83 ~ 99, tgδ < 7×10-4, αε= (-100~+100) ppm/°C. The crystal phases and microstructures are analyzed by X-ray diffraction and scanning electron microscope. It is found that the sintered ceramics is of biphase, comprising monoclinic CaTiSiO5 and orthorhombic CaTiO3, and the grains are mostly the small circular ones, having diameters of 1~29m. By adjusting the composing of the ceramic, a high frequency dielectric ceramic CaTiSiO5-CaTiO3, of which αε= (-50~+50) ppm/°C was attained.