Refining behavior due to a small mechanical force and re-formation process of the 2223 phase on heating have been examined for the samples with a nominal composition of Bi1.8Pb0.4Sr2Ca2Cu3.2Oz by XRD, TEM, ED, AFM and TG-DTA. The 2223 phase is brittle and easily cleaved at Bi-O double layers in its crystals by a small mechanical force, resulting in changing into the superfine powder with a thickness of 1/2c. On heating the ground powder at 500°C to 800°C in air, various phases were formed from the superfine powder.
