US 5262391

Patent Overview: US5262391A

Title: Oxide superconductor and process for preparation thereof

Patent number: US5262391A
Application number: US07/635,628
Inventor(s): Mitsuru Morita; Katsuyoshi Miyamoto; Kiyoshi Sawano; Shouichi Matsuda
Assignee: Nippon Steel Corporation (original and current assignee)
Priority date: 1989-05-02
Filing date: 1990-05-02
Publication/grant date: 1993-11-16
Legal status: Expired – Fee Related (anticipated expiration 2010-11-16 per the source listing)
Source: https://patents.google.com/patent/[US5262391](/patent/US5262391)/en

Purpose

The patent addresses a problem in oxide superconductors of the RE-Ba-Cu-O type: materials made by the melting method may have a high critical current density but a single-crystal texture, making it very difficult to form long wire rods or large-area bulk materials by conventional metal-working methods such as wire drawing, rolling, and post heat treatment.

Plain-language scope

The disclosed oxide superconductor comprises oxides of RE (at least one rare earth element, including Y), Ba, and Cu. It has a texture in which the crystal directions of the 123 phase in the matrix are uniform, large-angle grain boundaries with an azimuth difference larger than 20° are absent, and the 211 phase is finely dispersed (or an aggregate thereof). The superconductor is formed into a plate or wire, with the c-axis of the crystal uniform within ±30° to the plate-face normal, or in the range of 60° to 120° to that normal.

The preparation process inserts a quenched, solidified, formed body containing RE, Ba, and Cu into a heating furnace and moves a grain-forming temperature region for the 123 phase—from 1050° to 910° C., with a temperature gradient of at least 2° C.—at a speed lower than 0.4 cm/hr from the top end of the formed body toward the rear.

What the excerpt does not establish

The excerpt is partial; it omits claims, detailed embodiments, drawings, and most of the description. It therefore does not establish the full claim scope, exact compositions, working examples, measured properties, or the complete legal status.