V_2O_5-ZnO-TeO_2系ガラスの酸素感ガス特性

概要

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The dc electrical conductivity, σ, of 60V_2O_5・10ZnO・30TeO_2 glass (mol%) prepared by press-quenching was measured under Ar and O_2 gas atmospheres and oxygen gas-sensing properties were investigated at temperatures ranging from 303 to 473 K. Sigma at 443 K in 100% Ar was determined to be 8.53×10^<-4>S・cm^<-1>which was higher than σ in air (σ_<443K>=7.82×10^<-4>S・cm^<-1>), while σ_<443K> in 100% O_2 gas was 3.57×10^<-4>S・cm^<-1>lower than the σ value in air. This means that V^<4+> ions in the glass were oxdized by O_2 gas which diffused into the glass, resulting in an increase in V^<5+> with time. The experimental relationship between σ and oxygen partial pressure P_<O_<2>> agreed well with the theoretical relation σ ∝ P^<-1/4>_<O_<2>>. From data of dynamic change O_2 gas sensitivity, S, defined as the ratio of dcresistivity in Ar gas to that in O_2 gas, at 473 K was obtained to be 1.3 under 100% O_2 gas. Changes in σ by switching between 100% O_2 and 100% Ar were found to be reproducible. These changes were explained by the oxygen diffusion and desorption model. Good agreements was found between calculated σ and the experimental σ-t relationship. From these descussions, it is concluded that the present tellurite glass has a potential applicability to O_2 gas sensor.
社団法人日本セラミックス協会の論文
1995-03-01