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The chemical interactions between Bi 2 Sr 3 CaO 7 (Bi-2310) and Bi 2 Sr 2 Ca 0.8 Dy 0.2 Cu 2 O 8 (Bi-2212(Dy)) at 965°C were investigated by means of: (i) an interdiffusion couple and (ii) layers deposited by dip coating on oxidized nickel substrates. The samples were characterized by optical and electron microscopies, energy-dispersive x-ray (EDX) analysis and x-ray diffraction. It turns out that at the peritectic temperature of Bi-2212(Dy), the Bi-2310 phase reacts with the liquid phase resulting from the peritectic decomposition of the Bi-2212(Dy) phase. Dissolution of Bi-2310 leads to an enrichment in Sr and an impoverishment in Cu of the liquid phase, resulting in a shift of the composition of the insoluble phase towards the Ca-rich end of the (Ca, Sr)O solid solution.

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This paper proposes a systematic way to explore the effects of Na on Bi-2212 phase formation. The influence of sodium metal is correlated with the 2212 fraction formed in the sample. The effect on the sintering temperature and the importance of the substitution site is studied. Samples are characterized by X-ray diffraction analysis (XRD). Results clearly show that the 2212 phase content is enhanced and sintering temperatures can be lowered with regard to the undoped samples. D