The influence that trace concentrations of SiO2 have on improving grain-boundary conduction via precursor scavenging using additional heat treatment at 1200 °C for 40 h before sintering was investigated. At a SiO2-impurity level (SIL) ≤ 160 ppm by weight, the grain-boundary resistivity (ρgb) decreased to 20% of its value, while no improvement in grain-boundary conduction was found at a SIL ≥ 310 ppm. The correlation between the resistance per unit grain-boundary area, ρgb, and average grain size indicated that the inhomogeneous distribution of the siliceous phase in the sample with a SIL ≥ 310 ppm hampered the scavenging reaction.
|Number of pages||7|
|Journal||Journal of Materials Research|
|Publication status||Published - 2001 Aug 1|
ASJC Scopus subject areas
- Materials Science(all)