Bi_2Sr_2(Ca_xY_<1-x>)Cu_2O_yのCaの置換量, 酸素量と標準生成エンタルピー

概要

論文の詳細を見る
The enthalpy changes for the formation reaction, ΔH, of the superconducting related oxide Bi_2Sr_2(Ca_xY_<1-x>)Cu_2O_y system from the simple oxides, Bi_2O_3, SrO, CaO, Y_2O_3 and CuO, were determined by the solution calorimetric method using a perchloric acid solution containing 1×10^<-4> mol iron(II)perchlorate hexahydrate. The standard enthalpies of formation. Δ_fH°, of the Bi_2Sr_2(Ca_xY_<1-x>)Cu_2O_y system were calculated from the ΔH and Δ_fH° values of the simple oxides. The enthalpy changes for the formation reaction in terms of mole of atoms, ΔH_R, were calculated by dividing ΔH by v, the number of atoms in a formula unit. On the basis of enthalpy, discussion was developed on the ralation between the chemical stability of the complex oxide, the superconducting region and structure change. The enthalpy change for the formatin reaction, |ΔH_R|, of the Bi_2Sr_2(Ca_xY_<1-x>)Cu_2O_y system increased with increasing Ca substitution, x, and indicated a thermodynamic stability from the view point of enthalpy. The heats of solution of each sample composition, which was annealed at various temperatures, and oxygen partial pressures and oxygen contents, were measured. The enthalpy changes for the formation reaction, |ΔH_R|, were increased with increasing oxygen content for each composition and indicated thermodynamic stability.
社団法人日本セラミックス協会の論文
1997-09-01