A study on reaction mechanism in preparation of YBaCuO superconducting material from the thermoreaction method of nitrates

X-ray diffraction-coupled thermogravimetric differential thermal analysis (TG-DTA) has been used to study the reaction mechanism in the preparation of YBaCuO superconducting material from the thermoreaction method of nitrates. It is shown that there are three compound phases (Y2O3, CuO, Ba(NO3)2) before decomposition of Ba(NO3)2 and a mutual chemical reaction immediately occurs as soon as Ba(NO3)2 decomposes. The superconducting phase begins to form at a temperature of about 650°C and the suitable treatment temperature is between 750 and 800°C, which is much lower than that of the preparation reaction from oxides and/or carbonates.