Elastic properties and microstructure evolution of Zn2SnO4-spinel-containing composite ceramics based on tin oxide and zinc oxide

Ceramics based on tin oxide (SnO2) and zinc oxide (ZnO) were sintered at temperatures up to 1400 °C. Except for the end members, all these ceramics are two- or three-phase composites containing spinel phase (Zn2SnO4). Similar to pure SnO2 ceramics, also the spinel-rich composite (50:50 mixture) does not exhibit densification after sintering at 1400 °C. Spinel Zn2SnO4 is formed in all composites, with a major increase of spinel content at around 1000 °C. Young's modulus values, determined via impulse excitation, are between the exponential relation for convex pores and a benchmark relation for concave pores (or a percolation relation). The evolution of Young's modulus during sintering reveals significant differences between SnO2 (weak increase above 1000 °C), ZnO (significant increase above 800 °C) and the composites (intermediate). Spinel formation is revealed during heating by a distinct peak (elastic anomaly) at around 1000 °C.