Thermodynamic assessment of the BiOx–SrO–CaO system

An enhancement in structural and superconducting properties of Bi2212 epitaxial thin films grown by the Pechini sol–gel method

“…1c), the integration of different phases into CaSrBi 2 O 5 , CuSrO 2 , CaBi 2 O 4 and minor CuO phases occurs as a result of diffusion of oxides at 873 K for 60 min. According to Slobodin & Fotiev (1994) and Hallstedt & Gauckler (2004), the stable CaSrBi 2 O 5 phase can be synthesized at about 984 K, which is about 100 K above the pre-sintered temperature reported in this paper; this lowering of the synthesis temperature is a result of the superiority of the Pechini sol-gel method, for which the thermodynamic energy of synthesized nanomaterials is less than that of other chemical preparation methods.…”

“…This implies that there is complete complexing of metal ions and EDTA and there are no free metal ions to form nitrates in the precursor for the Pechini sol-gel method. According to Rawn et al (1994), the Bi 2 SrO 4 phase is only stable below 1098 K, but as an intermediate, the Bi 2 SrO 4 phase is synthesized at below 873 K (Hallstedt & Gauckler, 2004). Meanwhile the existence of a similar peak position of the Bi 2 O 3 phase at 28.274 in the XRD pattern of sample P3 indicates that the Bi 2 O 3 phase is emerging from the decomposition of the esterifiable organic skeleton.…”