U.S. patent application number 10/571245 was filed with the patent office on 2007-03-22 for nickel-based semifinished product having a cube recrystallization texture, corresponding method of production and use.
Invention is credited to Joerg Eickemeyer, Bernhard Holzapfel, Ralph Opitz, Dietmar Selbmann.
Application Number | 20070062613 10/571245 |
Document ID | / |
Family ID | 34258719 |
Filed Date | 2007-03-22 |
United States Patent
Application |
20070062613 |
Kind Code |
A1 |
Eickemeyer; Joerg ; et
al. |
March 22, 2007 |
Nickel-based semifinished product having a cube recrystallization
texture, corresponding method of production and use
Abstract
A nickel-based semifinished product has a cube recrystallization
texture and the semifinished product can e.g. be used as a support
for physicochemical coatings having a highly microstructured
orientation. Such supports are e.g. suitable as substrates for
ceramic coatings such as are used in the field of high-temperature
supraconductivity. In this case, the product is used in
supraconducting magnets, transformers, motors, tomographs and
supraconducting current paths. There is provided a nickel-based
semifinished product that has improved performance characteristics
when used as a support for physicochemical coatings having a highly
microstructured orientation. Especially the semifinished product
should have a higher-grade, thermally more stable cube texture
while substantially preventing the formation of grain boundary
grooving. For this purpose, Ag in the microalloy range is added to
the material of the semifinished product, the added Ag being not
more than 0.3 atomic percent. The inventive semifinished product is
e.g. suitable as a support for physicochemical coatings having a
highly microstructured orientation.
Inventors: |
Eickemeyer; Joerg; (Dresden,
DE) ; Selbmann; Dietmar; (Colmnitz, DE) ;
Opitz; Ralph; (Dresden, DE) ; Holzapfel;
Bernhard; (Kreischa, DE) |
Correspondence
Address: |
JORDAN AND HAMBURG LLP
122 EAST 42ND STREET
SUITE 4000
NEW YORK
NY
10168
US
|
Family ID: |
34258719 |
Appl. No.: |
10/571245 |
Filed: |
September 8, 2004 |
PCT Filed: |
September 8, 2004 |
PCT NO: |
PCT/EP04/52083 |
371 Date: |
July 20, 2006 |
Current U.S.
Class: |
148/286 ;
148/426; 148/676 |
Current CPC
Class: |
C22C 19/03 20130101;
C22F 1/10 20130101 |
Class at
Publication: |
148/286 ;
148/676; 148/426 |
International
Class: |
C22C 19/03 20060101
C22C019/03; C22F 1/10 20060101 C22F001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 10, 2003 |
DE |
103 42 965.4 |
Claims
1.-6. (canceled)
7. A semi-finished product on a nickel basis, comprising: a
nickel-based material including one of technically pure nickel and
a nickel alloy; and silver added to said nickel-based material in a
micro-alloying range not exceeding 0.3 atom percent, said
semi-finished product having a cubic recrystallization texture.
8. A semi-finished product according to claim 7, wherein: said
nickel-based material is said nickel alloy; and said nickel alloy
contains at least one of molybdenum and tungsten as alloying
elements.
9. A semi-finished product according to claim 7, wherein a cubic
textured nickel oxide layer with a textured portion of more than
90% is present on said semi-finished product.
10. A semi-finished product according to claim 8, wherein a cubic
textured nickel oxide layer with a textured portion of more than
90% is present on said semi-finished product
11. A semi-finished product according to claim 7, wherein said
semi-finished product serves as a base for chemical coatings, said
semi-finished product further comprising a physical chemical
coating on said base, said chemical coating having a high-grade
microstructural alignment.
12. A semi-finished product according to claim 111 wherein said
base and coating define, at least in part, one of a flat wire
high-temperature superconductor and a strip-shaped high-temperature
superconductor.
13. A semi-finished product according to claim 8, wherein said
semi-finished product serves as a base for chemical coatings, said
semi-finished product further comprising a physical chemical
coating on said base, said chemical coating having a high-grade
microstructural alignment.
14. A semi-finished product according to claim 13 wherein said base
and coating define, at least in part, one of a flat wire
high-temperature superconductor and a strip-shaped high-temperature
superconductor.
15. A semi-finished product according to claim 9, wherein said
semi-finished product serves as a base for chemical coatings, said
semi-finished product further comprising a physical chemical
coating on said base, said chemical coating having a high-grade
microstructural alignment.
16. A semi-finished product according to claim 15 wherein said base
and coating define, at least in part, one of a flat wire
high-temperature superconductor and a strip-shaped high-temperature
superconductor.
17. A method for the production of a semi-finished product,
comprising: adding silver to a nickel-based material in a
micro-alloying range which does not exceed 0.3 atom %, said
nickel-based material including one of technically pure nickel and
a nickel alloy; processing said semi-finished product by hot
working; carrying out high-grade cold working of more than an 80%
reduction in thickness of said semi-finished product; and
subjecting said semi-finished product to a recrystallizing
annealing to achieve a substantially cubic texture.
18. A method according to claim 17, wherein said step of adding
includes one of melt metallurgical and powder metallurgical
processes.
19. A method according to claim 17, wherein said step of carrying
out high-grade cold working results in forming of said
semi-finished product into one of a strip and flat wire.
20. A method according to claim 17, further comprising heat
treating the semi-finished product in an oxidizing atmosphere one
of during and after said step of subjecting said semi-finished
product to the recrystallizing annealing, for the purpose of
growing a cubic textured nickel oxide layer.
21. A method according to claim 17, further comprising: forming the
semi-finished product into a base; and coating said base with a
physical chemical coating having a high-grade microstructural
alignment.
22. A method according to claim 21, wherein said step of forming
creates a shape of said base suitable for use as at least one of a
flat wire high-temperature superconductor and a strip-shaped
high-temperature superconductor.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to a semi-finished product on a nickel
basis with a cubic recrystallization texture and a method for its
production.
[0002] The semi-finished product can be used, for example, as a
base for physical, chemical coatings with a high-grade
microstructural alignment. Such bases are suitable, for example, as
substrates for ceramic coatings, as used in the field of
high-temperature superconduction. In this case, such bases are used
in superconducting magnets, transformers, motors, tomographs or
superconducting current paths.
[0003] It is known that polycrystalline metals with a cubic,
face-centered lattice, such as nickel, copper and aluminum, after a
prior high-grade cold working by rolling, can develop a pronounced
texture with a cubic layer during the subsequent recrystallization
(G. Wasserman: Texturen metallischer Werkstoffe (Textures of
Metallic Materials), Springer, Berlin, 1939). Metallic strip
textured in this way, especially nickel strips, are also used as a
base for metallic coatings, ceramic buffer layers and ceramic
superconducting layers (U.S. Pat. No. 5,741,377). The suitability
of such metal strip as a substrate material depends primarily on
the achievable degree of texturing and on the stability of the
texture in the region of the temperatures, at which the collecting
processes are carried out.
[0004] Semi-finished products for the preparation of
high-temperature superconductors are already known and consist of
Ni--Cr, Ni--Cr--V, Ni--Cu and similar alloys (U.S. Pat. Nos.
5,964,966 and 6,106,615).
[0005] Nickel alloys with molybdenum and tungsten are also known
for these purposes (DE 100 05 861 C1).
[0006] The known semi-finished products have the following
disadvantages: [0007] after a cold working process and
recrystallization annealing, nickel has a great tendency to form a
coarse grain structure, which is disadvantageous for achieving the
high-great cubic texture; [0008] during the recrystallization heat
treatment, especially at higher temperatures (800.degree. to
1150.degree. C.) cold worked nickel strip has a great tendency to
form rifts at grain boundaries; [0009] the rifts at grain
boundaries may represent an appreciable impediment to the formation
of a high-grade, biaxial cubic texture; and [0010] substrate
material with rifts at grain boundaries is less suitable as a base
for epitaxial layer depositions, for example, for buffer layers and
superconducting layers.
SUMMARY OF THE INVENTION
[0011] It is an object of the invention to develop a semi-finished
product on a nickel basis, which has improved use properties for
use as a base for physical, chemical coatings with a high-grade
microstructural alignment. In particular, the semi-finished product
is to have a higher grade, thermally more stable cubic texture and
the formation of rifts at grain boundaries is to be largely
avoided. The development of a method for the preparation of this
semi-finished product is included in this task.
[0012] This objective is accomplished owing to the fact that the
material of the semi-finished product contains an addition of
silver in the micro-alloying range, the addition of silver not
exceeding 0.3 atom percent.
[0013] In accordance with an appropriate development of the
invention, the nickel alloy may contain molybdenum and/or tungsten
as alloying elements.
[0014] There may be a cubic textured nickel oxide layer with a
textured portion of more than 90% on the inventive semi-finished
product. This layer is suitable as a diffusion barrier and enables
qualitatively high-grade coatings to be produced, especially under
oxidizing conditions.
[0015] The formation of a high-grade cubic texture is favored and
the thermal formation of grain boundary rifts on the nickel surface
of the semi-finished product is hindered by the inventive addition
of silver. Moreover, the addition of silver enables a high-grade
nickel oxide layer, which is provided with a cubic texture, to be
grown on the semi-finished product.
[0016] A feature of the inventive method of preparing the
semi-finished product is that, initially, by melt metallurgical or
powder metallurgical means, including mechanical alloying, a
semi-finished product is prepared, which consists of technically
pure nickel or a nickel alloy, in which a silver addition in the
micro-alloying range is contained in an amount of less than 0.3
atom percent. Subsequently, the semi-finished product is processed
by means of hot working, followed by a high-grade cold working
involving a more than 80% reduction in thickness to a strip or flat
wire. Finally, this semi-finished product is subjected to a
recrystallizing annealing in order to achieve a cubic texture.
[0017] Subsequently or during the recrystallizing annealing, the
semi-finished product, so prepared, may be heat treated pursuant to
the invention in an oxidizing atmosphere for the purpose of growing
a cubic textured nickel oxide layer.
[0018] Pursuant to the invention, the semi-finished product may be
used as a base for physical, chemical coatings with a high-grade
microstructural alignment, especially for the production of
wire-shaped or strip-shaped, high-temperature superconductors.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a photograph depicting sharp recrystallization
cubic texture; and
[0020] FIGS. 2(a) and 2(b) are photographs rotated 45.degree. with
respect to the texture of the nickel strip.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] The invention is explained in greater detail below, by means
of examples, which show the successful testing of the invention. A
portion of the test results is documented in FIGS. 1 and 2 and in
Table 1 below.
Example 1
[0022] Technically pure nickel, which has a degree of purity of
99.9 atom percent and has been alloyed with 0.01 atom percent of
silver, is cast in a mold. The ingot is rolled at 1000.degree. C.
into the square dimension (22.times.22 mm2), annealed to homogenize
it and quenched. Subsequently, the square material is reworked with
chip removal in order to obtain a defect-free surface for the
subsequent cold working by rolling. The cold working is carried out
with a reduction in thickness by rolling of more than 80%, in this
case, 99.6%. The resulting nickel strip has a thickness of 80 mm
and a high-grade, rolled texture. It is subsequently subjected to a
30-minute annealing treatment at 550.degree. C. in a non-oxidizing
gas atmosphere.
[0023] The result is an exceptionally sharp recrystallization cubic
texture, as is evident from the photograph of FIG. 1. The
proportion of crystallites with a cubic state is 98% and the
proportion of small angle grain boundaries also is 98%. The half
value width of the intensity of the (111) pole in X-ray diffraction
is FWHM=4.4.degree..
Example 2
[0024] Technically pure nickel, which has a degree of purity of
99.9 atom percent and has been alloyed with 0.01 atom percent of
silver, is melted in a vacuum induction furnace and poured into a
mold. The ingot is rolled at 1000.degree. C. to the square
dimension (22.times.22 mm2), annealed to homogenize it and
quenched. Subsequently, the square material is reworked with chip
removal in order to obtain a defect-free surface for the subsequent
cold working by rolling. The cold working is carried out with a
reduction in thickness by rolling of more than 80%, in this case,
99.6%. The resulting nickel strip has a thickness of 80 mm and a
high-grade, rolled texture. It is subsequently subjected to a
30-minute annealing treatment at 550.degree. C. in a reducing gas
atmosphere.
[0025] The result is an almost complete recrystallization cubic
texture. Subsequently, the strip is exposed to a 5-minute oxidation
in pure oxygen gas at 1150.degree. C.
[0026] The resulting nickel oxide layer has a cubic texture, 97% of
the grains having the cubic state. This texture is rotated through
45.degree. with respect to the texture of the nickel strip (see
FIGS. 2(a) and 2(b)). The FWHM value of the (111) pole is of the
order of 6.2.degree..
Example 3
[0027] Technically pure nickel, which has been alloyed with 0.01
atom percent of silver, is melted and cast in a mold. The ingot is
rolled at 1000C into the square dimension (22.times.22 mm2),
annealed to homogenize it and quenched. Subsequently, the square
material is reworked with chip removal in order to obtain a
defect-free surface for the subsequent cold working by rolling. The
cold working is carried out with a reduction in thickness by
rolling of 85%. The resulting nickel strip has a thickness of 3 mm
and is subsequently subjected to a 30-minute annealing treatment at
850.degree. C. for recrystallization. After that, the surface is
cleaned and the strip is worked further cold to a thickness of 80
mm. Finally, it is annealed at 850.degree. C. for 45 minutes in a
reducing atmosphere in order to produce the cubic texture.
Example 4
[0028] Technically pure nickel, with the addition of 4.0 atom
percent of tungsten powder and 0.1 atom percent of silver powder,
is processed by powder metallurgical means. After compression,
tempering and hot working, a rod material (12.times.12 mm2) is
obtained. The surface is reworked with chip removal, in order to
obtain a defect-free surface for the following cold working by
rolling. Starting from dimensions of 10.times.10 mm2, the cold
rolling is carried out until the finished product has a thickness
of 80 mm. The edge regions of the strip are severed and discarded.
The nickel strip obtained is subsequently subjected to a 30 minute
annealing at 550.degree. C. in a reducing atmosphere for the
recrystallization. Subsequently, the strip is annealed a second
time for 8 minutes at 1100.degree. C. in a reducing atmosphere, in
order to obtain a thermally highly stressable cubic state.
[0029] With the values of the substrates Nos. 5 and 6, the Table 1
below shows the positive effect of the inventive addition of silver
on the FWHM (111) values in comparison with the state of the art
(substrates Nos. 1 to 4). TABLE-US-00001 TABLE 1 FWHM (111) Value
Recrystallized Recrystallized Substrate at 550.degree. C. for 30
minutes at 850.degree. C. for 30 minutes 1 Ni 8.3.degree. -- 2 Ni +
0.1 7.4.degree. 7.2.degree. atom % of Mo 3 Ni + 0.1 8.8.degree.
8.6.degree. atom % of W 4 Ni 7.9.degree. 6.8.degree. 5 Ni + 0.95
4.8.degree. 5.1.degree. atom % of Ag 6 Ni + 0.01 4.4.degree.
5.3.degree. atom % of Ag
* * * * *