Effect of Niobium doping on structural, thermal, sintering and electrical properties of Bi4V1.8Cu0.2O10.7

Doping Bi4V1.8Cu0.2O10.7 with niobium has led to the formation of the Bi4V1.8Cu0.2−xNbxO10.7+3x/2 solid solution. X-ray diffraction and thermal analysis have shown that only the compound with image presents a tetragonal symmetry with a image polymorph while the other compositions are of β polymorph. The influence of sintering temperature on the microstructure of the samples was investigated by the scanning electron microscopy (SEM). The ceramics sintered at temperatures higher than 820 °C present micro-craks. The evolution of the electrical conductivity with temperature and the degree of substitution has been investigated by impedance spectroscopy. Among all compositions studied the sample with image presents the highest value of the conductivity.