A method for preparing bi-2212 precursor powder by suspension sintering

Abstract

The invention discloses a method for preparing Bi-2212 precursor powder through a suspension sintering method. The method comprises the specific processes: mixing Bi2O3, Ca(OH)2, SrCO3 and CuO, then preparing oxalate mixed powder by adopting an oxalate coprecipitation method, and then sequentially carrying out heating and heat preservation, preliminary sintering, high-temperature sintering and phase-forming sintering to obtain the Bi-2212 precursor powder. The oxalate mixed powder prepared by the coprecipitation method is used as raw material powder, the quality purity of a Bi-2212 phase in the Bi-2212 precursor powder is effectively improved, and a step-by-step suspension sintering method is combined; through phase formation is effectively promoted, the problem of powder segregation caused by melting of a low-melting-point phase is solved, the problem of incomplete final phase formation caused by too low local temperature due to large heat absorption of the Bi-2212 phase directly generated from oxide powder is avoided, the uniformity and quality of the Bi-2212 precursor powder are greatly improved, and the method is suitable for mass production.

Description

technical field [0001] The invention belongs to the technical field of preparing Bi-2212 superconducting wire strips, and in particular relates to a method for preparing Bi-2212 precursor powder by a suspension sintering method. Background technique [0002] Bi-2212 high temperature superconductor (Bi 2 Sr 2 CaCu 2 o x ) is the most important branch of high-temperature superconducting materials. Due to its easy processing and high current-carrying performance, Bi-2212 wire has become one of the most promising high-temperature superconducting materials. The Bi-2212 precursor powder has a decisive effect on the current-carrying performance of the Bi-2212 wire. The standard of high-performance precursor powder is: the powder is high-purity Bi-2212 phase, small and uniform particle size, as little as possible impurity and impurity. High-quality Bi-2212 precursor powder puts forward high requirements for powder preparation technology. [0003] For the five-membered compoun...

AI Technical Summary

Problems solved by technology

The main problem is that most of the Bi-containing compounds are low-melting compounds, and it is difficult to avoid the formation of these low-melting compounds in the conventional static sintering process, which makes the powder prone to macrosegregation and affects the quality of the powder.

However, the original body (fog droplets) prepared by the conventional spray pyrolysis method contains a large amount of high specific hot water, which causes the original body to enter the high-temperature furnace, and the furnace temperature is significantly reduced. Therefore, in order to ensure the decomposition temperature, the original body must be The addition rate of the body is controlled at a very small level, which greatly limits the output of the powder. In addition, the spray pyrolysis powder needs to adopt conventional static sintering, which will lead to the melting of part of the residual Bi-containing low melting point phase and affect the quality of the final powder.

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