Apparatus and method of manufacturing metallic or inorganic strands having a thickness in the micron range by melt spinning

Patent metadata

Field	Value
Publication number	US-10987728-B2
Application number	US-201515321479-A
Country	US
Kind code	B2
Filing date	Aug 6, 2015
Priority date	Aug 7, 2014
Publication date	Apr 27, 2021
Grant date	Apr 27, 2021

Abstract

Apparatus for producing elongate strands of metal comprises a rotatable wheel having a circumferential surface, at least one nozzle for directing a molten metal onto the circumferential surface and a collection means for collecting solidified strands of metal formed. The solidified strands are formed on the circumferential surface from the molten metal and are separated from the circumferential surface by centrifugal force generated by rotation of the wheel. The circumferential surface has a circumferentially extending structure having circumferentially extending edges and recesses formed between or bounded by the edges, and by an apparatus for controlling a gas pressure applied to the liquid metal which moves the liquid metal through the nozzle opening and delivers it to the circumferential surface of the rotatable wheel. The nozzle has a rectangular cross-section with a width of the nozzle opening in the circumferential direction of rotation of the wheel and a length transverse to the circumferential surface of the wheel which is greater than the width. A method and a wheel adapted for use in the apparatus are also claimed.

First claim

The invention claimed is:

1. An apparatus for producing elongate strands of metal, the apparatus comprising a rotatable wheel having a circumferential surface, the circumferential surface having circumferentially extending edges and recesses formed between or bounded by the edges, each recess of the recesses defining a depth and a width with the depth being greater than 100 μm and the width being greater than 100 μm, a nozzle defining a nozzle opening having a width of between 10 μm to 100 μm for directing a molten metal onto the circumferential surface and to form solidified strands of metal on the circumferential surface from the molten metal, wherein the nozzle has a rectangular cross-section having a width of the nozzle opening in the circumferential direction of rotation of the wheel and a length transverse to the circumferential surface of the wheel which is greater than the width W, and wherein an apparatus is provided for controlling a gas pressure applied to the liquid metal which moves the liquid metal through the nozzle opening and delivers it to the circumferential surface of the rotatable wheel, wherein said wheel is mounted and configured to rotate within a chamber having an atmosphere at a higher pressure than ambient pressure.

2. The apparatus in accordance with claim 1 , wherein the circumferential recesses defining the edges have a radial depth greater than 50 μm; and/or
wherein the recesses have a cross-sectional shape selected from the group of members consisting of semi-circular, symmetrically v-shaped, asymmetrically v-shaped, rectangular and trapezoidal.

3. The apparatus in accordance with claim 1 , there being peripherally extending lands at the circumferential surface of the wheel, each land being disposed between two circumferentially extending recesses.

4. The apparatus in accordance with claim 3 , wherein said lands have widths of 1 mm or less.

5. The apparatus in accordance with claim 1 , wherein the metal strands have the form of ribbons having a width of 200 μm or less.

6. The apparatus in accordance with claim 1 , wherein the metal strands have a thickness of 50 μm or less.

7. The apparatus in accordance with claim 1 , wherein the metal strands have at least one transverse dimension of 50 μm or less and a length at least ten times greater than said at least one transverse dimension.

8. The apparatus in accordance with claim 1 , wherein the rotatable wheel is temperature controlled.

9. The apparatus in accordance with claim 1 , wherein the wheel is made of one of a metal, a metal alloy, a ceramic material and graphite or is a wheel of a base material having a layer or type made of one of a metal, a metal alloy, a ceramic material, graphite and a vapour deposited carbon; and/or
wherein said wheel is mounted to rotate within the chamber having the atmosphere, the atmosphere being at least one of air and an inert gas.

10. The apparatus in accordance with claim 1 , wherein a deflector is provided upstream of the nozzle in the direction of rotation of the wheel to deflect boundary layer gas from the circumferentially extending surface prior to depositing molten metal on the surface via the nozzle.

11. The apparatus in accordance with claim 1 , wherein the gas pressure applied to the molten metal is selected in the range from 50 mbar to 1 bar overpressure relative to a pressure external to the nozzle.

12. The apparatus in accordance with claim 1 , wherein a motor is adapted to drive the wheel at a frequency of greater than 85 Hz for a copper wheel having a diameter of 200 mm.

13. The apparatus in accordance with claim 1 , wherein the circumferential surface of the wheel has transversely extending features to control the length of the strands produced.

14. The apparatus in accordance with claim 1 , wherein the material of the wheel is selected so that it does not readily bond to the molten metal.

15. A method for producing elongate strands of metal having at least one transverse dimension of 50 μm or less and a length at least ten times greater than said at least one transverse dimension, the method comprising the steps of directing a molten metal through a nozzle having a rectangular cross-section with a width of a nozzle opening in a circumferential direction of rotation of a rotating wheel and a length transverse to a circumferential surface of the rotating wheel which is greater than the width onto the circumferential surface of the rotating wheel, by applying a gas pressure to the molten metal to move it through the nozzle opening and deliver it to the circumferential surface of the rotating wheel, providing the circumferential surface of the rotating wheel with circumferentially extending edges and recesses formed between or bounded by the edges and collecting solidified strands of metal formed on the circumferential surface from the molten metal and separated from the circumferential surface by centrifugal force generated by rotation of the rotating wheel, the method further comprising the steps of controlling the width of the nozzle opening, controlling the gas pressure applied to the molten metal to move it through the nozzle opening and deliver it to the circumferential surface of the rotating wheel and controlling a speed of rotation of the rotating wheel to reduce a flow of molten metal onto the circumferential surface of the rotating wheel to a level at which it is concentrated by the forces that are acting at said circumferentially extending edges and recesses formed between or bounded by the edges and using these edges to concentrate the molten metal at the edges to produce the desired elongate strands of metal, the nozzle opening having a width of between 10 μm to 100 μm and wherein the rotating wheel is mounted and configured to rotate within a chamber having an atmosphere at a higher pressure than ambient pressure.

16. The method in accordance with claim 15 , wherein the flow of molten metal is reduced to a level at which the elongated strands have a width of 200 μm to 1 μm.

17. The method in accordance with claim 15 , wherein the metal strands have a thickness of 50 μm to 1 μm.

Assignees

• Max Planck Gesellschaft

Inventors

• Spatz Joachim P
• Watari Moyu
• Mager Reinhard

Classifications

• B22D11/005

  of wire (casting on wire B22D19/14) · CPC title

• B22D11/0611 Primary

  formed by a single casting wheel, e.g. for casting amorphous metal strips or wires · CPC title

• B22D11/0651

  Casting wheels (B22D11/0682 takes precedence) · CPC title

• B22D11/16

  Controlling or regulating processes or operations · CPC title