Fabrication, microstructure and electrical conductivity of V2O5 ceramics

V2O5 gels corresponding to the formula V2O5·nH2O with n = 2.07, 0.5, and 0.2 have been prepared by the hydrolysis of VO(OC2H5)3, followed by washing and drying. After dehydration, V2O5 crystallizes at 310° to 400°C. V2O5 powders with strip-like particles are produced after heating at 630°C. Well-densified V2O5 ceramics (97.7% of theoretical) have been fabricated by the combined use of hot pressing (630°C/2h/30MPa) and hot isostatic pressing (630°C/1h/196MPa). The texture is of a plate structure, the grain being ≈ 30 μm long and ≈ 6 μm wide. Electrical conductivities have been measured in the temperature range of 25° to 600°C. Activation energies are determined to be 0.09 and 0.18 eV for initial and final stages, respectively.