Papers by Author: Yang Zhang

Abstract: A new type of pellet binder was prepared with oxalic acid as sodium silicate chemical modification agent in this paper, the compressive strength of which improved obviously. It improved from 0.6 KN/a to 2.4 KN/a, when the amount of oxalic acid is 8%. Meanwhile, carboxyl introduced at 390°C started carbonization decomposition, and pelletizing properties wouldn't be affected without new pellet impurity. The analysis shows that adding oxalic acid introduces carboxyl only in the binder, but doesn't generate new functional groups; Polymer layer formed by carboxyl adsorption on sodium silicate gel particle surface limits colloidal particle growing up, and plays roles of refining colloidal particle and improving the bonding strength.

Abstract: The precursor of Ca2Co2O5 was prepared by coprecipitation method. The bulk Ca2Co2O5 samples were prepared by conventional sintering and Spark Plasma Sintering (SPS), respectively. The relative density of bulk Ca2Co2O5 ceramic, which was prepared by conventional sintering is about 75%; while the samples prepared by SPS has a density of 98%. The thermoelectric properties were enhanced by SPS, compared with samples prepared with conventional sintering. The maximum powerfactor of the conventional sintering and SPS samples are 2.70×10-4W∙m-1∙K-2 and 3.85×10-4 W∙m-1∙K-2, respectively.