Effect of Heat Treatment Temperature on Phase Formation and Properties of Bi-2212 Spray Pyrolysis Powder

Abstract:

Bi₂Sr₂CaCu₂O_x (Bi-2212) primary powder was prepared by spray pyrolysis method. The effect of heat treatment temperature on powder phase formation and properties was systematically studied. The weight loss and phase transformation of the primary powder were analyzed by TG-DSC, the phase composition of the powder was analyzed by XRD, the microstructure of the powder was observed by SEM, and the superconducting physical properties of the samples were determined by the magnetization method. It was found that at 535~570℃, the nitrate residues in the primary powder of Spray Pyrolysis gradually decomposed; at 605~640℃, the Bi-2201 phase was formed; when the temperature reached 775℃, the Bi-2212 phase began to form, With the increase of heat treatment temperature, the crystallinity of the powder continued to increase, and the content of Bi-2212 phase first increased and then decreased. 860℃ was the best phase-forming sintering temperature. In addition, through the in-depth analysis of the DSC curve and the M-T curve, it was found that the low temperature pre-decomposition at 640°C first, and then the high temperature phase-forming sintering at 860°C could further improve the quality of the final powder.

Key words:Bi-2212 powder; Spray Pyrolysis; Bi-2212 phase; Phase temperature; Two-step sintering method