Subsolidus Phase Relations of the CoOx-CuO-SrO System

Abstract

AbtractThe subsolidus phase relations of the CoO x -CuO -SrO system were investigated in air. The samples were equilibrated at 900C. The pseudo-ternary section contains three stoichiometric binary oxide phases (Sr 2 CuO 3 , SrCuO 2 and Sr 14 Cu 24 O 41-δ ) and a binary oxide solid solution: Sr 6+x Co 5 O 15+δ (0 ≤ x ≤ 0.36). Two binary phases extend into the ternary system forming solid solutions, i.e. Sr 14 Cu 24-x Co x O 41-δ (0 ≤ x ≤ 5) and Sr 6+x Co 5-y Cu y O 15+δ (0 ≤ x ≤ 0.36, 0 ≤ y ≤ 1.0). The Sr 6+x Co 5 O 15+δ solid solution was found to undergo a phase separation into a mixture of Sr 6 Co 5 O 15-δ and Sr 14 Co 11 O 33 upon annealing at 600°C. This transformation is reversible.

Subsolidus phase equilibria of the CuO – SrO – ZnO pseudoternary system in air at 900 °C

“…Nevertheless, whereas ternary sections involving these oxides with rare-earth oxides have been systematically determined (refe rence [2] and references therein), combinations of CuO and (BaO, SrO or CaO) with a transition metal oxide are still poorly investi-gated. In the case of SrO, the exceptions encompass systems in which the transition element is V [3], Nb [4,5], Fe [6], Ti [7,8], Zr [8], Hf [8], Ta [9], W [10] and Co [11]. The CuO -SrO -ZnO system does not appear to have been stu died.…”