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New Processing of High Tc Superconducting Oxide Powder

IP.com Disclosure Number: IPCOM000101054D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 75K

Publishing Venue

IBM

Related People

Kang, SK: AUTHOR [+3]

Abstract

Disclosed is a process to produce high Tc superconducting oxides with higher apparent physical density, and therefore higher current density. The powder processing technique used in the present investigation is called as "mechanical alloying" (1) which has been extensively used in the production of superalloys for applications as jet turbine materials (2,3). Mechanical alloying is a dry, high-energy ball milling process that produces composite metal alloy powders with a uniform dispersion of refractory particles in a complex alloy matrix. The mechanical alloying process is usually carried out in high-energy attrition mills or special ball mills.

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New Processing of High Tc Superconducting Oxide Powder

       Disclosed is a process to produce high Tc superconducting
oxides with higher apparent physical density, and therefore higher
current density.  The powder processing technique used in the present
investigation is called as "mechanical alloying" (1) which has been
extensively used in the production of superalloys for applications as
jet turbine materials (2,3).  Mechanical alloying is a dry,
high-energy ball milling process that produces composite metal alloy
powders with a uniform dispersion of refractory particles in a
complex alloy matrix.  The mechanical alloying process is usually
carried out in high-energy attrition mills or special ball mills.
When the mechanical alloying process is complete, the powder is
expected to be chemically and microstructurally homogeneous and
heavily cold-worked as a result of attrition or ball milling (4).

      A powder mixture of Y2O3BaO and CuO was charged in a hardened
steel vial with stainless steel balls.  This steel vial was processed
in a Spex mixer mill at a speed of 1200 rpm.  The milling time was
varied from 30 minutes to 4 hours.  The processed powder was then
pressed into a disk for sintering.  It was sintered at 950oC, 40
hours in air, followed by another heat treatment at 750oC, 20 hours
in O2, and subsequently cooled slowly to room temperature.

      The newly processed Y-Ba-Cu-oxide materials have been
characterized by measuring Tc, density, magnetic susceptibility,
crystal structure and impurity content. The measured Tc values of the
new materials are very close to those of the conventionally processed
ones, approximately 90oK.

      The apparent densities of the newly processed Y-Ba-Cu-O
superconductors were measured to be 4.5 and 5.6 g/cm3 for the 0....