Effect of zinc oxide doping on the grain boundary conductivity of Ce_(0.8)Ln_(0.2)O_(1.9)ceramics (Ln = Y, Sm, Gd)

摘要

The effect of zinc oxide (ZnO) doping on the densification behaviours and the electrical properties of Ce_(0.8)Ln_(0.2)O_(1.9) (Ln - Y, Sm, Gd) ceramics are examined. The addition of ZnO (1 mol%) reduces the sintering temperature by ~200℃ and improves the grain boundary behaviours significantly. Both the apparent grain boundary conductivity (骭(gb)~(opp)) and the specific grain boundary conductivity (骭(gb)~(opp)) are investigated. Under the same synthetic conditions, ZnO doping leads to a larger grain size and a higher (骭(gb)~(opp)) The SEM and EDS results indicate that ZnO-doping can induce Si enrichment on the surfaces of samples (i.e. reducing the content of Si at grain boundaries), which may explain the improvements occurs in the grain boundary conductions.