The role of the formation of buffer V2O5 inclusions in the composition of composite ZrO2 – Al2O3 ceramics on the change in strength characteristics

Abstract

The paper presents the assessment results of the effect of addition of V₂O₅ dopant to the composition of composite ZrO₂ – Al₂O₃ ceramics and the formation of buffer inclusions on resistance to external mechanical influences and enhancement of resistance to cracking under mechanical loads. During the studies conducted, it was established that the addition of the V₂O₅ dopant to the composition of ceramics with a concentration above 0.1 M leads to the formation of buffer inclusions in the intergranular space formed by ZrO₂ grains and the Al₂O₃ matrix, while the formation of buffer inclusions is due to the low melting point of V₂O₅, resulting in the melting of vanadium oxide during sintering and subsequent vitrification and crystallization during cooling in the intergranular space. During assessment of the strength characteristics, in particular hardness, crack resistance and compressive strength, it was found that at low dopant concentrations, strengthening is caused by structural changes associated with size effects, which are expressed in the growth and coarsening of ZrO₂ grains in the Al₂O₃ matrix. At concentrations above 0.1 M, the growth in resistance to external influences is due to the formation of buffer inclusions, the filling of the intergranular space with which leads to the inhibition of crack formation processes and an increase in resistance to mechanical loads.