Effect of sintering atmosphere on phase stability,and electrical conductivity of proton-conducting Ba(Zr_(0.84)Y_(0.15)Cu_(0.01))O_(3-δ)

摘要

The phase stability and electrical conductivity of a proton-conducting oxide, Ba(Zr_(0.84)Y_(0.15)Cu_(0.01))O_(3 δ) (BZYCu), sintered under various atmospheres was systematically investigated. The partial pressures of oxygen (Po_2) and barium (P_(Ba)) were used as the tunable experimental parameters to control the surrounding atmosphere during sintering. According to the analysis, the potentially volatile species BaCO_3, formed by the decomposition of BZYCu under a CO_2-containing atmosphere at around 600 ℃, was found to induce barium losses by evaporation. These barium losses, and the associated Y_2O_3 segregation, were the decisive factor in determining the phase stability and electrical conductivity of the resulting BZYCu; both of these properties deteriorated with barium evaporation. Maintaining the optimum balance of Po_2 and P_(Ba) during sintering is crucial for minimizing Y_2O_3 segregation by kinetically suppressing the volatilization of barium.