Li_2Ti_3O_7の相変化に対するNb_2O_5添加効果

概要

論文の詳細を見る
Nb_2O_5-added R (ramsdellite) phase was synthesized by the melt-quenching method. Addition of 3 to 5 mol% Nb_2O_5 accelerated the R→H (hexagonal phase) transformation, retarded the H→S+r (spinel and rutile) successive decomposition reaction, and stabilized the H phase at high temperatures. These effects were possibly caused by the preferential incorporation of Nb_2O_5 in the H phase. The phase changes in the Nb_2O_5-added R phase occurred similarly to the non-added R phase following the route quenched-R→H→S+r→R during heating and R→H→S+r during cooling, respectively. The R phase containing 3 mol% Nb_2O_5 was heated to 850℃ at 2℃/min in air, then quenched, and the H phase was obtained although very small amounts of rutile and spinel were contained. Lattice constants of the obtained H phase were a=0.8777(8) nm and c=6.988(2) nm, and the effect of Nb_2O_5 addition was hardly recognized. The linear thermal expansion coefficient of the H phase was determined to be α=1.34×10^<-5>K^<-1> between room temperature and 900℃. Investigation on the phase changes in the H phase during heating clarified those in the R phase.
社団法人日本セラミックス協会の論文
1993-06-01