Method of producing polycrystalline Y-358 superconductor

Patent metadata

Field	Value
Publication number	US-11130712-B2
Application number	US-201816139755-A
Country	US
Kind code	B2
Filing date	Sep 24, 2018
Priority date	Sep 24, 2018
Publication date	Sep 28, 2021
Grant date	Sep 28, 2021

Abstract

A method of producing polycrystalline Y 3 Ba 5 Cu 8 O y (Y-358) whereby powders of yttrium (III) oxide, a barium (II) salt, and copper (II) oxide are pelletized, calcined at 850 to 950° C. for 8 to 16 hours, ball milled under controlled conditions, pelletized again and sintered in an oxygen atmosphere at 900 to 1000° C. for up to 72 hours. The polycrystalline Y 3 Ba 5 Cu 8 O y thus produced is in the form of elongated crystals having an average length of 2 to 10 μm and an average width of 1 to 2 μm, and embedded with spherical nanoparticles of yttrium deficient Y 3 Ba 5 Cu 8 O y having an average diameter of 5 to 20 nm. The spherical nanoparticles are present as agglomerates having flower-like morphology with an average particles size of 30 to 60 nm. The ball milled polycrystalline Y 3 Ba 5 Cu 8 O y prepared under controlled conditions shows significant enhancement of superconducting and flux pinning properties.

First claim

The invention claimed is:

1. A method of producing polycrystalline Y 3 Ba 5 Cu 8 O y , comprising:
pelletizing powders of yttrium (III) oxide, barium (II) salt, and copper(II) oxide to produce a pelletized mixture;
calcining the pelletized mixture at a first temperature in the range 850-900° C. to form a first calcined mixture;
grinding the first calcined mixture to form a first intermediate calcined mixture, then
calcining the first intermediate calcined mixture at a temperature in the range 850-900° C. to form a second calcined mixture, wherein the second calcined mixture is free from carbonate,
ball milling the second calcined mixture to produce a ball milled sample; and
sintering the ball milled sample at a second temperature in the range 900-1000° C. to form the polycrystalline Y 3 Ba 5 Cu 8 O y ,
wherein the polycrystalline Y 3 Ba 5 Cu 8 O y is in the form of elongated crystals having an average length of 2 to 10 μm and an average width of 1 to 2 μm, and are embedded with spherical nanoparticles of yttrium deficient Y 3 Ba 5 Cu 8 O y having an average diameter of 5 to 20 nm, wherein the spherical nanoparticles are in the form of flower-like agglomerates having an average particle size of 30 to 60 nm.

2. The method of claim 1 , wherein the barium (II) salt is a barium carbonate.

3. The method of claim 1 , wherein the pelletizing includes uniaxially pressing a mixture of yttrium (III) oxide, barium (II) salt, and copper(II) oxide powders under an applied pressure of about 100 MPa.

4. The method of claim 1 , wherein the second calcined mixture is ball milled using a planetary ball milling technique.

5. The method of claim 1 , wherein the second calcined mixture is ball milled with stainless-steel balls and vials.

6. The method of claim 1 , wherein the second calcined mixture is ball milled with a ball to powder weight ratio of 1:1 to 5:2.

7. The method of claim 1 , wherein the second calcined mixture is ball milled at a rotational speed of 300 to 600 rpm.

8. The method of claim 1 , wherein the second calcined mixture is ball milled for 3 to 5 hours.

9. The method of claim 1 , wherein the second calcined mixture is ball milled noncontinuously in increments of 20 to 30 minutes separated by cooling off periods of 5 to 10 min.

10. The method of claim 1 , wherein the ball milled sample is pelletized under a uniaxial pressure of about 750 MPa.

11. The method of claim 1 , wherein the ball milled sample is sintered in an oxygen atmosphere at 950° C. for up to 72 hours.

12. The method of claim 1 , wherein the polycrystalline Y 3 Ba 5 Cu 8 O y has a normalized transport critical current density, JctN, of 0.040 to 0.042 under an applied transverse magnetic field (μ 0 H) of 100 mT.

13. The method of claim 1 , wherein the polycrystalline Y 3 Ba 5 Cu 8 O y has a magnetization critical current density J cm of 13×10 3 to 15×10 3 A·cm −2 and 550 to 570 A·cm −2 at 0 Tesla and 1 Tesla, respectively.

14. The method of claim 1 , wherein the polycrystalline Y 3 Ba 5 Cu 8 O y , has a lower critical magnetic field (B c1 (0)) of 7 to 7.25 Tesla and an upper critical magnetic field (B c2 (0)) of 580 to 585 Tesla.

15. The method of claim 1 , wherein the polycrystalline Y 3 Ba 5 Cu 8 O y has an estimated critical current density at temperature T=0K (J c (0)) of 320×10 3 to 330×10 3 A·cm −2 .

16. A method of producing polycrystalline Y 3 Ba 5 Cu 8 O y , comprising:
pelletizing powders of yttrium (III) oxide, a barium (II) salt, and copper(II) oxide to produce a pelletized mixture;
calcining the pelletized mixture at 700 to 1,000° C. to produce a calcined mixture;
ball milling the calcined mixture to produce a ball milled sample; and
sintering the ball milled sample at 800 to 1,100° C. to form the polycrystalline Y 3 Ba 5 Cu 8 O y , wherein y is a number that varies to maintain electro-neutrality of the polycrystalline Y 3 Ba 5 Cu 8 O y ; and
wherein the polycrystalline Y 3 Ba 5 Cu 8 O y is in the form of elongated crystals having an average length of 2 to 10 μm and an average width of 0.5 to 3 μm, and spherical nanoparticles of yttrium deficient Y 3 Ba 5 Cu 8 O y with an average diameter of 5 to 20 nm disposed on the elongated crystals, wherein the spherical nanoparticles are in the form of flower-like agglomerates having an average particle size of 30 to 60 nm.

Assignees

• Univ Imam Abdulrahman Bin Faisal

Inventors

• Slimani Yassine

Classifications

• Y02E40/60

  Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment · CPC title

• C04B2235/786

  Micrometer sized grains, i.e. from 1 to 100 micron · CPC title

• C04B35/6262

  of calcined, sintered clinker or ceramics · CPC title

• C30B29/225

  based on rare earth copper oxides, e.g. high T-superconductors · CPC title

• C04B2235/783

  Bimodal, multi-modal or multi-fractional · CPC title