Bi-Pb-Sr-Ca-Cu-O系高温相の化学的および機械的安定性(III) : 粉砕粉の形態と反応過程

概要

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Chemical and mechanical stability of the high-Tc phase (2223) was examined by XRD, SEM and TEM. An interesting segregation reaction occurred when annealed at low temperature (500-840°C) in air. The phase precipitated on the mother crystals has been identified as Sr2.5Bi0.5Pb3Ca2CuOz which is isostructural with Sr3Pb2.03Cu0.75O8. On the other hand, high resolution TEM showed that the high Tc phase changed into three types of fine powders by mechanical grinding; i.e., fine crystals of the original 37 Å-phase, fine powder of a new phase (thickness is less than 37Å) and an amorphous powder. It was found that heating of these fine powder provides another formation process of the 2223 phase compared with the conventional one.
社団法人粉体粉末冶金協会の論文