2000 年 49 巻 6Appendix 号 p. 144-149
An attempt was made to improve the electrical properties of SnO2-glass composites by dispersing Cu particles with low resistivity and positive temperature coefficient of resistance (TCR) in the glass matrix. Cu metal particles were precipitated by reducing Cu2O previously dissolved into the matrix glass by adding LaB6 as a reducing agent. The effect of the glass particle size, which influences the homogeneity of LaB6 dispersion in the powder mixture before firing, on the Cu precipitation in the glass matrices and the electrical properties of the glass composites was investigated. When fine glass powder was used, dense glass composites were obtained. When coarse glass powder was used, LaB6 easily reduced SnO2 as well as Cu2O and thus the amount of metal precipitation was larger than that in the glass composite made from fine glass powder. However, in the glass composites prepared by the coarse glass powder, large pores formed by the evaporation of SnO, a reduction intermediate from SnO2. The glass composite prepared by the fine glass powder showed higher electrical conductivity (σ) and smaller negative TCR than that made from the coarse glass powder although the amount of metal formed by reducing reaction was small. However, when the fine glass powder was used, the glass composite showed more significant decrease in the σ and TCR at high LaB6 content than the glass composite made from the coarse glass powder.
