HK1075071B - Metal strip for epitaxial coating and method for production thereof - Google Patents

Description

Metal strip for epitaxial coating and method for producing same

Technical Field

The invention relates to a metal strip consisting of a composite layer for epitaxial coating and a method for producing the same. Such metal strips can advantageously be deposited from YBa, for example₂Cu₃O_xUse of a carrier tape comprising a biaxially-woven layer of high-temperature superconductor material. Such superconductors are particularly suitable for use in the field of energy technology.

Background

Metal strips based on Ni, Cu and Ag are known, suitable for epitaxial coating with biaxially textured layers (US 5739086; US 5741377; US 5964966; US 5968877). They are produced by cold rolling with a deformation rate higher than 95% and subsequent recrystallization annealing, in which a texture (cubic texture) is formed that enhances {001} <100 >.

In particular, the development of Ni-and Ag-based matrix materials is being tightened around the world (J.E. Mathis et al, Jap.J.appl.Phys.37.1998; T.A. Gladstone et al, Inst.Phys.Conf.Ser.No. 167, 1999). It is known to roll and recrystallize Ni alloys containing typically more than 5% of one or more alloying elements in an effort to increase the strength of the material, either by solid solution quenching (US 5964966; g.cellutano et al, int.journal of model physics b, 13, 1999, s.1029; r.nekkani et al, Presentation at the Applied superior. conf., Virginia Bcach, Virginia, sept.17-22, 2000), or by rolling and recrystallising a composite material of Ni with a material of higher tensile strength (t.wataneet, Presentation at thc superior. conf., Virginia Beach, screen.17-22, 2000).

During solid solution quenching, a critical additive content exists above which the cubic texture can no longer be formed. This phenomenon for copper-zinc alloys (Cu-Zn alloys with increased Zn content) has been intensively studied and appears to be universally valid (H.Hu et al, trans.AIME, 227, 1963, S.627; G.Wasserman, J.Grewen: Texturen metalloscher Werkstoffe, Springer-Verlag Berlin/G ö ttingen/Heidelberg). Since the strength increases with the alloy concentration, the maximum strength is also relevant. A second limitation is that the strength of the material is already high when it is deformed by rolling. Therefore, when increasing the deformation rate, very high rolling forces are required, which, on the one hand, inevitably places greater demands on the rolling mill, and, on the other hand, it is technically difficult to carry out extremely uniform rolling deformations, which are necessary for the formation of the desired high cube texture.

In the case of increasing the strength by rolling a composite material, there is also a problem that a high-strength material requires a high rolling force when it is highly deformed. As the two materials forming the composite material have different mechanical properties, the heterogeneity of the deformed microstructure appears during rolling, thereby reducing the quality of the cubic texture which can be achieved during the recrystallization process.

The intermetallic phases have a significantly higher strength than solid solution alloys. However, they are generally very brittle and cannot be used to produce thin ribbons with a pronounced cubic texture.

Particularly the so-called intermetallic gamma-and gamma' -phases (Ni) are known₃Al，Ni₃Ti，Ni₃Nb), the strength does not decrease with increasing temperature like a solid solution, but even increases. Therefore, metal strips strengthened by these phases produce much higher strengths than conventional metal strips, precisely during the coating at critically high temperatures (> 600 ℃).

Disclosure of Invention

The aim of the invention is to provide an epitaxially coated metal strip having a particularly high strength. The invention also relates to a method for producing such a high-strength metal strip without any problems in terms of production.

This object is achieved with a metal strip consisting of a composite layer, which consists of at least one biaxially textured base layer of the metals Ni, Cu, Ag or alloys thereof and at least one further metal layer, wherein the respective further metal layer consists of one or more intermetallic phases or of a metal or an alloy containing one or more intermetallic phases therein.

According to a first embodiment of the invention, in the case of a biaxially textured base layer made of Ni or a Ni alloy, the respective further metal layer is made of an intermetallic phase of the base metal and at least one metal Al, Ta, Nb, Ti or an alloy thereof.

According to a second object of the invention, in the case of a biaxially textured substrate consisting of Ni or a Ni alloy, the respective other metal layer consists of at least one metal Al, Ta, Nb, Ti or an alloy thereof, which contains an intermetallic phase of the metal Al, Ta, Nb, Ti or an alloy thereof with the substrate metal.

The intermetallic phase may be composed of NiAl, Ni₃Al，Al₃Ni₂，Al₃Ni，NiTa，NiTa₂，Ni₃Ta，Ni₃Nb, and/or Ni₆Nb₇And (4) forming.

According to a further embodiment of the invention, in the case of a biaxially textured base layer consisting of Cu or a Cu alloy, the respective further metal layer consists of an intermetallic phase of Cu or a Cu alloy and Zn.

In the case of a biaxially textured base layer consisting of Cu or a Cu alloy, the respective other metal layer also consists of Zn, in which an intermetallic phase of Cu or a Cu alloy and Zn is contained.

In this respect, the intermetallic phase of Cu or Cu alloy and Zn is β -and/or γ -brass.

According to a further embodiment of the invention, in the case of a biaxially textured base layer made of Ag or an Ag alloy, the respective further metal layer is made of an intermetallic phase of Ag or an Ag alloy and Nd.

In the case of a biaxially textured base layer composed of Ag or an Ag alloy, the respective other metal layers are also composed of Nd, containing an intermetallic phase of Ag or an Ag alloy and Nd.

In this connection, the intermetallic phase of Ag or Ag alloy and Nd consists of Ag₅₂Nd₁₄，Ag₂Nd, and/or AgNd.

According to an advantageous embodiment of the invention, the composite layer consists of two biaxially textured base layers and one further metal layer, the further metal layer being arranged between the biaxially textured layers.

To produce such a metal strip, the invention comprises a method in which a composite layer is first produced, consisting of at least one layer of the metals Ni, Cu, Ag or alloys thereof suitable for biaxial texturing and at least one further metal layer. In this connection, it is necessary to include an element in the other metal layer which can form an intermetallic phase with the layer suitable for biaxial texturing.

Thereafter, the composite layer is rolled into a strip at a deformation ratio of at least 90%. Finally, the desired cubic texture is formed by interdiffusion at the interface of the intermetallic phase composite layers in the layer suitable for biaxial texture and other layers by means of a heat treatment of the strip between 300 ℃ and 1100 ℃.

The composite layer is produced in a suitable manner by electroplating and is rolled into a belt with a deformation rate of at least 95%. The heat treatment of the strip is particularly suitable for temperatures between 500 ℃ and 900 ℃.

A variant of the method according to the invention consists in first producing biaxially textured tapes of Ni, Cu, Ag or alloys thereof by rolling and recrystallization. Such a strip is subsequently coated with at least one other metallic phase comprising at least one metal containing elements that can form intermetallic phases in the biaxially textured strip. The coating method can be, for example, electrolytic, chemical or else deposition from the vapor phase. During the subsequent heat treatment, stable intermetallic phases are formed starting from the boundary layer.

As an alternative to the coating, the biaxially textured tape may be wetted on one side with a liquid other metal phase and then diffused into the biaxially textured tape, so that an intermetallic phase is formed starting from the surface of the biaxially textured tape, as long as the melting point of the biaxially textured tape is significantly higher than the other metal phase.

With the method according to the invention, a high-strength biaxially textured metal strip can be produced in a comparatively simple manner. In this respect, it is particularly advantageous that the metal strip in the deformation process phase still has a low strength and a high ductility, since only in the final annealing treatment does the high-strength intermetallic phases form in the metal strip. The cubic texture is not affected by the different kinetics of the recrystallization and diffusion processes.

The metal strip according to the invention is particularly suitable for deposition from YBa₂Cu₃O_xUse of a carrier tape comprising a biaxially-woven layer of high-temperature superconductor material. Such superconductors are particularly suitable for use in energy sources

The technical field is application.

Detailed Description

The invention is illustrated in detail below with the aid of examples.

Example 1

A three-layer composite layer consisting of the metals Ni and Al is produced by roll plating, the layer sequence being Ni/Al/Ni. The thickness of the Ni layer was 1.5mm, and the thickness of the Al layer was 0.5 mm. The composite layer was rolled to a strip thickness of 80 μm. The tape was then placed in a reducing atmosphere at a temperature of 600 ℃ for several hours. The ribbon recrystallizes during the first few minutes of this heat treatment. In the continuation of this heat treatment, different stoichiometric NiAl phases are created and added to the boundary layer.

The finished tape has a high degree of cubic texture on its surface and is particularly suitable for double-sided epitaxial coating with biaxially textured layers.

The yield point of the tape at room temperature was 100MPa and did not change until 600 ℃. This material therefore has a greatly increased strength at the temperature of the coating metal compared to conventional, in particular solid solution hardened metal strips.

Example 2

A three-layer composite layer consisting of the metals Ni and Nb is produced by roll plating, the layer sequence being Ni/Nb/Ni. The thickness of the Ni layer was 1.5mm, and the thickness of the Nb layer was 0.5 mm. The composite layer was rolled to a strip thickness of 40 μm. The tape was then placed in a reducing atmosphere at 900 ℃ for 1 hour. The ribbon recrystallizes during the first few seconds of such heat treatment. Different stoichiometric NiNb phases are created and added to the boundary layer as annealing continues.

The finished tape has a high degree of cubic texture on the surface and is also suitable for double-sided epitaxial coating using biaxially textured layers.

The yield point of the tape at room temperature was 85MPa and did not change until a temperature of 600 ℃. This material therefore has a greatly increased strength at the temperature of the coating metal compared to conventional, in particular solid solution hardened metal strips.

Example 3

Pure Ni biaxially textured tapes of thickness 40 μm were produced by rolling and recrystallization, heated to 800 ℃ and coated with a 10 μm thick Al film on the uncoated side. Due to the heat treatment, the Al film melts and Al diffuses into the Ni, forming a different stoichiometric NiAl phase by interdiffusion from the surface of the Ni strip.

The yield point of the tape at room temperature was 90MPa and did not change until 600 ℃. This material therefore has a greatly increased strength at the temperature of the coating metal compared to conventional, in particular solid solution hardened metal strips.

Example 4

A three-layer composite layer consisting of the metals Cu and Zn is produced by roll plating, the layer sequence being Cu/Zn/Cu. The thickness of the Cu layer was 1.5mm and the Zn layer was 0.7 mm. The composite layer was rolled to a 50 μm thick strip. The tape was then heated to 800 ℃ at 30K/min and held for 60 minutes. During this annealing, an enhanced texture is first formed, followed by the formation of a different stoichiometric brass phase starting from the Cu-Zn interface.

The finished belt has a high degree of cubic texture on its surface, suitable for double-sided epitaxial coating with a biaxially textured layer. The yield point of the strip was 80MPa at room temperature and decreased to 30MPa at 750 ℃ with increasing temperature. Therefore, the strip strength is significantly higher than other biaxially textured Cu alloy strips using stronger rolling.

Claims (19)

1. Metal strip for epitaxial coating, consisting of a composite layer, characterized in that the composite layer consists of at least one biaxially textured base layer of the metals Ni, Cu, Ag or alloys thereof and at least one further metal layer, wherein the respective further metal layer consists of one or more intermetallic phases or of a metal or an alloy containing one or more intermetallic phases therein.

2. The metal strip defined in claim 1 wherein, in the case that the biaxially textured substrate is comprised of Ni or a Ni alloy, each of the other metal layers is comprised of an intermetallic phase of the substrate metal and at least one of the metals Al, Ta, Nb, Ti or alloys thereof.

3. The metal strip defined in claim 1 wherein, in the case that the biaxially textured substrate is comprised of Ni or a Ni alloy, each of the other metal layers is comprised of at least one metal of Al, Ta, Nb, Ti or an alloy thereof containing an intermetallic phase of said metal of Al, Ta, Nb, Ti or alloy thereof with the substrate metal.

4. A metal strip according to claim 2 or 3, wherein the intermetallic phase is formed from NiAl, Ni₃Al，Al₃Ni₂，Al₃Ni，NiTa，NiTa₂，Ni₃Ta，Ni₃Nb, and/or Ni₆Nb₇And (4) forming.

5. The metal strip of claim 1 wherein, in the case of a biaxially textured base layer comprised of Cu or a Cu alloy, each of the other metal layers is comprised of an intermetallic phase of said Cu or Cu alloy and Zn.

6. The metal strip of claim 1 wherein, in the case of a biaxially textured base layer comprised of Cu or a Cu alloy, each of the other metal layers is comprised of Zn with an intermetallic phase of Cu or Cu alloy and Zn.

7. The metal strip defined in claim 5 or claim 6 wherein the intermetallic phase of Cu or Cu alloy and Zn consists of β -and/or γ -brass.

8. The metal strip of claim 1 wherein, in the case of a biaxially textured base layer comprised of Ag or an Ag alloy, each of the other metal layers is comprised of an intermetallic phase of said Ag or Ag alloy and Nd.

9. The metal strip of claim 1 wherein, in the case of a biaxially textured base layer comprised of Ag or an Ag alloy, each of the other metal layers is comprised of Nd, with the intermetallic phase of Ag or an Ag alloy and Nd contained therein.

10. A metal strip according to claim 8 or 9 wherein the intermetallic phase of Ag or Ag alloy and Nd is formed from Ag₅₂Nd₁₄，Ag₂Nd, and/or AgNd.

11. The metal strip of claim 1 wherein the composite layer is comprised of two biaxially textured base layers and an additional metal layer, wherein the additional metal layer is disposed between the biaxially textured layers.

12. Method for producing a metal strip according to one of claims 1 to 11, characterized in that a composite layer is first produced, consisting of at least one layer of the metals Ni, Cu, Ag or alloys thereof suitable for biaxial texturing and at least one further metal layer, wherein at least one element which can form an intermetallic phase with the layer suitable for biaxial texturing is contained in the further metal layer, after which the composite layer is rolled into a strip with a deformation rate of at least 90%, and finally the desired cubic texture is formed in the layer suitable for biaxial texturing and the further layer by interdiffusion at the interface of the intermetallic phase composite layer by means of a strip heat treatment between 300 ℃ and 1100 ℃.

13. The method of claim 12, wherein the composite layer is fabricated by electroplating.

14. The method of claim 12, wherein the composite layer is rolled at a deformation ratio of at least 95%.

15. Method for producing a metal strip according to one of claims 1 to 11, characterized in that a biaxially textured strip of Ni, Cu, Ag or alloys thereof is first produced by rolling and recrystallization, and this strip is subsequently coated with at least one further metal phase comprising at least one metal containing elements which form intermetallic phases in the biaxially textured strip, stable intermetallic phases being formed during the subsequent heat treatment starting from the boundary layer.

16. The method of making a metal strip according to claim 15 where electrolytic, chemical or vapor deposition is used for the coating metal.

17. The method of claim 12 or 15, wherein the heat treatment is performed at a temperature between 500 ℃ and 900 ℃.

18. The method of manufacturing metal strip according to claim 15 where the biaxially textured strip is wetted on one side with the other metal phase in a liquid state provided that the melting point of the biaxially textured strip is significantly higher than the other metal phase,

19. use of a metal strip according to claims 1 to 11 as a deposit from YBa₂Cu₃O_xUse of a carrier tape of biaxially-woven layers of high-temperature superconductor material for the production of a tape-shaped high-temperature superconductor.