A kind of preparation method of magnesium-doped neodymium barium copper oxide large seed crystal

A neodymium barium copper oxide and seed crystal technology, applied in the field of high-temperature copper oxide superconducting materials, can solve the problems of low efficiency and cumbersome process, and achieve the effects of high efficiency, good thermal stability and easy control

Inactive Publication Date: 2017-11-14
TIANJIN NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, their preparation method requires the use of NdBa 2 Cu 3 o 7-δ and Nd 4 Ba 2 Cu 2 o 10 Two kinds of precursor powders, the process is cumbersome and the efficiency is low

Method used

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  • A kind of preparation method of magnesium-doped neodymium barium copper oxide large seed crystal
  • A kind of preparation method of magnesium-doped neodymium barium copper oxide large seed crystal
  • A kind of preparation method of magnesium-doped neodymium barium copper oxide large seed crystal

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] (1) Preparation of Nd 1.6 Ba 2.3 Cu 3.3 o x Precursor powder:

[0027] Take 45.6589g Nd 2 o 3 Mix well with 59.8162g BaO, 44.5249g CuO initial powder, namely Nd 2 o 3 The molar ratio of BaO and CuO primary powder is 1.6:2.3:2.3, sintered at 920°C for 30 hours, and the nominal composition is Nd 1.6 Ba 2.3 Cu 3.3 o x precursor powder;

[0028] (2) Press the precursor block:

[0029] Take 20g Nd 1.6 Ba 2.3 Cu 3.3 o x Precursor powder, add 0.2g MgO initial powder, that is, in Nd 1.6 Ba 2.3 Cu 3.3 o x Add 1% (w / w) MgO initial powder to the precursor powder, mix well, then put it into a cylindrical mold with a diameter of 26mm, and press it into a precursor block;

[0030] (3) Melting and growing Mg-doped neodymium-barium-copper-oxygen multi-domain bulk material:

[0031] Put the precursor block in Al 2 o 3 On the gasket, 5 MgO single grains of equal height are placed in the middle, and then the whole is put into the well-type furnace, and the temperatu...

Embodiment 2

[0035] In step (2) of pressing the precursor block, take 20g Nd 1.6 Ba 2.3 Cu 3.3 o x Precursor powder, add 0.1g MgO initial powder, that is, in Nd 1.6 Ba 2.3 Cu 3.3 o x Add 0.5% (w / w) MgO initial powder to the precursor powder, mix well, then put it into a cylindrical mold with a diameter of 26mm, and press it into a precursor block. Other steps are identical with embodiment 1. Obtain Mg-doped neodymium barium copper oxide large seed crystal.

[0036] image 3The surface topography of the as-prepared Mg-doped NdBaCuO multidomain bulk is shown. It can be seen from the figure that the sample exhibits a typical multi-domain morphology, and the largest domain size is above 15 mm. Therefore, a large seed crystal with a size above 5mm×5mm can be cleaved on a large domain region. The large seed crystal under cleavage was applied to a method of preparing nanocomposite yttrium-barium-copper-oxide superconducting bulk by powder melting-liquid phase infiltration (application ...

Embodiment 3

[0038] In step (2) of pressing the precursor block, take 20g Nd 1.6 Ba 2.3 Cu 3.3 o x Precursor powder, add 0.3g MgO initial powder, that is, in Nd 1.6 Ba 2.3 Cu 3.3 o x Add 1.5% (w / w) MgO initial powder to the precursor powder, mix well, then put it into a cylindrical mold with a diameter of 26mm, and press it into a precursor block.

[0039] In the step (3) of melting and growing Mg-doped NdBCO multi-domain bulk material, the precursor block is placed on Al 2 o 3 On the gasket, 5 MgO single grains of equal height are placed in the middle, and then the whole is put into the well-type furnace, and the temperature is raised to 920°C at a heating rate of 240°C per hour, and the temperature is kept for 10 hours; The heating rate was raised to 1140°C and kept for 1 hour; then the temperature was lowered to 1085°C at a cooling rate of 60°C per hour, and then slowly cooled to 1045°C at a cooling rate of 0.5°C per hour, and cooled to room temperature with the furnace to obtai...

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Abstract

The invention discloses a preparation method of a magnesium-doped neodymium-barium-copper-oxygen large seed crystal, which comprises the following steps: preparing Nd1.6Ba2.3Cu3.3Ox precursor powder, pressing a precursor block, carrying out flux growth to obtain an Mg-doped neodymium-barium-copper-oxygen polydomain block, and splitting the seed crystal. The single Nd1.6Ba2.3Cu3.3Ox precursor powder is utilized to successfully prepare the Mg-doped neodymium-barium-copper-oxygen seed crystal, and thus, the method is simple and efficient. Besides, the Mg-doped neodymium-barium-copper-oxygen polydomain block grown by the method contains the large domain region with the size of up to 15mm, and therefore, the next series of large seed crystal with the size of up to 5mm*5mm can be easily split. Compared with the traditionally used small seed crystal, the large seed crystal has higher heat stability and can more easily control the orientation consistency in the induced block growth process.

Description

technical field [0001] The invention belongs to the technical field of high-temperature copper oxide superconducting materials, and in particular relates to a preparation method of magnesium-doped neodymium-barium-copper-oxygen large seed crystals. Background technique [0002] The single-domain RE-Ba-Cu-O (RE=Y, Gd, Sm, Nd, etc.) high-temperature superconducting bulk material guided by the top seed technology can effectively eliminate the weak connection existing in polycrystalline or multi-domain samples phenomenon, so the sample can carry a very high bulk critical current, showing a high capture magnetic field and magnetic levitation performance, and has broad application prospects in micro superconducting magnets, superconducting motors, magnetic levitation bearings, energy storage flywheels, and maglev trains. . [0003] Because the single-domain RE-Ba-Cu-O superconducting bulk is nucleated and directional grown under the induction of the seed crystal, the quality of t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B29/22C30B9/04
Inventor 李国政
Owner TIANJIN NORMAL UNIVERSITY
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