A comparative study of spark plasma and conventional sintering of undoped SnO2 sputtering targets

SnO2 ceramics were fabricated by spark plasma sintering (SPS) and conventional (pressureless) sintering techniques using undoped submicron SnO2 powders. The effect of sintering temperature and dwell time on the densification behavior, phase evolution, and microstructural development of sintered ceramics were investigated. The relative density of SPSed ceramics increased when dwell time was raised from 1 to 10 min at 950 degrees C. However, full densification was prevented by the decomposition of SnO2 to Sn. The decomposition started after similar to 10 min at 950 degrees C. In parallel to these observations, as sintering temperature increases, the elemental Sn in agglomerated form increases. On the other hand, the relative densities of conventionally sintered ceramics (at 1200 degrees C-1400 degrees C) were relatively low (i.e., 63% relative density), and abnormal grain growth was observed due to the shift in sintering mechanisms to evaporation-condensation as a dominant mechanism. Since the undoped SnO2 ceramics, SPSed at 950 degrees C for 5 min under 30 MPa exhibit 93% relative density, high chemical purity, homogeneous grain size distribution, and smaller average grain size, they demonstrate great potential as sputtering targets for the production of high-quality thin film gas sensors.

Automated summary

SnO2 ceramics were prepared by SPS and conventional sintering techniques, and their densification behavior and microstructural development were studied. SPSed ceramics exhibited higher relative density compared to conventionally sintered ceramics, and showed potential for producing high-quality thin film gas sensors.