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

A bi-2212, sintered powder technology, applied in chemical instruments and methods, bismuth compounds, inorganic chemistry, etc., can solve problems affecting powder quality, powder macro segregation, furnace temperature reduction, etc., to improve uniformity and quality, reduce Equipment cost, effect of preventing powder segregation

Active Publication Date: 2020-12-22
NORTHWEST INSTITUTE FOR NON-FERROUS METAL RESEARCH
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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.

Method used

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

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] This embodiment includes the following steps:

[0037] Step 1. Put Bi 2 o 3 , Ca(OH) 2 , SrCO 3 Mix with CuO according to the mass ratio of Bi:Sr:Ca:Cu=1.95:1.95:0.9:1.95, then prepare a nitrate mixed solution, and then adopt the oxalate co-precipitation method to prepare an oxalate mixed powder;

[0038] Step 2: Put the oxalate mixed powder obtained in step 1 into a box furnace for heating and heat preservation, take it out after cooling with the furnace for grinding, then put it into a continuous rotating automatic sintering furnace for preliminary sintering, and grind it after taking it out to obtain Primary sintered powder; the specific process of heating and heat preservation is as follows: firstly, the temperature is raised to 200°C at a rate of 40°C / h and held for 2h, and then the temperature is raised to 450°C at a rate of 40°C / h and held for 2h; the preliminary sintered The heating rate is 40°C / h, the sintering temperature is 450°C, and the holding time is ...

Embodiment 2

[0043] This embodiment includes the following steps:

[0044] Step 1. Put Bi 2 o 3 , Ca(OH) 2 , SrCO 3 Mix with CuO according to the mass ratio of Bi:Sr:Ca:Cu=2.2:2.2:1:2.2, then be formulated with nitrate mixed solution, and then adopt oxalate co-precipitation method to prepare oxalate mixed powder;

[0045] Step 2: Put the oxalate mixed powder obtained in step 1 into a box furnace for heating and heat preservation, take it out after cooling with the furnace for grinding, then put it into a continuous rotating automatic sintering furnace for preliminary sintering, and grind it after taking it out to obtain Primary sintered powder; the specific process of heating and heat preservation is as follows: firstly, the temperature is raised to 250°C at a rate of 80°C / h and held for 5h, and then the temperature is raised to 500°C at a rate of 80°C / h and held for 5h; the preliminary sintered The heating rate is 80°C / h, the sintering temperature is 500°C, and the holding time is 5h;...

Embodiment 3

[0050] This embodiment includes the following steps:

[0051] Step 1. Put Bi 2 o 3 , Ca(OH) 2 , SrCO 3 Mix with CuO according to the mass ratio of Bi:Sr:Ca:Cu=2:2:0.95:2, then prepare a nitrate mixed solution, and then adopt the oxalate coprecipitation method to prepare an oxalate mixed powder;

[0052] Step 2: Put the oxalate mixed powder obtained in step 1 into a box furnace for heating and heat preservation, take it out after cooling with the furnace for grinding, then put it into a continuous rotating automatic sintering furnace for preliminary sintering, and grind it after taking it out to obtain Primary sintered powder; the specific process of heating and heat preservation is as follows: firstly, the temperature is raised to 230°C at a rate of 60°C / h and held for 3 hours, and then the temperature is raised to 470°C at a rate of 60°C / h and held for 3 hours; the preliminary sintered The heating rate is 60°C / h, the sintering temperature is 470°C, and the holding time is...

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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...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G29/00C04B35/453C04B35/626
CPCC01G29/006C04B35/453C04B35/62605C04B2235/3208C04B2235/3213C04B2235/3281C04B2235/661
Inventor 郝清滨李成山徐晓燕刘国庆焦高峰郑会玲白利锋金利华刘学谦张胜楠李高山贾佳林熊晓梅冯建情
Owner NORTHWEST INSTITUTE FOR NON-FERROUS METAL RESEARCH
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