Investigation of Phase Formation in Ceramic Based on Zn, Sn, and Ti Oxides

Solid-phase sintering was used to make ceramic from a mixture of ZnO, SnO₂, and TiO₂ nanopowders used as precipitation-strengthening and arc-quenching components in silver-based electrocontact materials. The phase formation and microstructure of the resulting material were studied by electron microscopy, energy-dispersive microanalysis, and x-ray phase analysis. It was found that a dispersed structure of size 0.5 – 1.0 μm forms from the Zn₂TiO₄ and ZnO phases at sintering temperature 1123 K, and the samples have quite high porosity. Solid-phase reactions in the ZnO/TiO₂ system at T_sint = 1123 K effect the formation of two-phase ZnO/Zn₂TiO₄ ceramic with zinc and tin oxide phases in residual amounts. At sintering temperature 1443 K grain growth occurs, Zn₂SnO₄ becomes the predominant phase, and a certain amount of zinc and tin oxide phases remains. There is no manifestations of titanium-containing phases (presumably TiO₂ and Zn₂TiO₄), probably because of their low content.