Study of the phase formation mechanisms in composite ZrO2-Al2O3 ceramics with the addition of a stabilizing V2O5 dopant

Abstract

This article presents the results of the mechanisms of composite ZrO₂-Al₂O₃ ceramics at the addition of a stabilizing V₂O₅ dopant, a change in the concentration of which results in in grain size enlargement, porosity reduction, and the formation of a substitution Zr(V)O₂ phase in the structure at dopant concentrations greater than 0.10 M. During the conducted studies it was established that the addition of the V₂O₅ dopant to the composition of composite ZrO₂-Al₂O₃ ceramics leads to the enlargement of the ZrO₂ grains in the Al₂O₃ matrix. Moreover, the enlargement of the ZrO₂ grains results in porosity reduction, as well as a change in the grains from a spherical shape to an irregular diamond shape, which is an alloy of smaller grains, the fusion of which is caused by the thermal effect during the melting of the V₂O₅ oxide. Moreover, if the concentration of the stabilizing V₂O₅ dopant in the composition of ceramics grows by more than 0.1 M, this leads to the formation of a finely dispersed fraction of V₂O₅ with an orthorhombic type of crystal lattice in the structure, the weight contribution of which is within 4-9% depending on the stabilizing dopant concentration. The formation of the partial substitution phase of Zr(V)O₂ observed at concentrations of the V₂O₅ dopant in the composition of ceramics above 0.1 M is due to the effects of thermal melting of vanadium oxide, which results in the initialization of grain coarsening processes due to sintering, as well as partial substitution of zirconium ions by vanadium ions in the composition of the monoclinic phase.