Superconducting Ba1 xKxBiO3 (delta) pellets were synthesized by solid state reaction followed by sintering. Thermo-gravimetric and differential thermo-gravimetric analysis (TG-DTA) of the mixture of nitrates was carried out to study the reactions during the phase formation. The effect of different sintering temperatures on the phase formation was studied. The X-ray diffraction data confirms the formation of superconducting Ba0.6K0.4BiO2.23 phase at 700 degrees C. The surface morphological studies as a function of sintering temperature were studied by SEM. It is observed that the pellets prepared by solid state reaction followed its sintering at 700 degrees C shows the superconducting transition at 26.8 K. (c) 2008 Elsevier B.V. All rights reserved.