Metal foil for base material and producing method thereof

Patent metadata

Field	Value
Publication number	US-9902134-B2
Application number	US-201113885309-A
Country	US
Kind code	B2
Filing date	Nov 16, 2011
Priority date	Nov 17, 2010
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A metal foil including: a steel layer whose thickness is 10 to 200 μm; an Al-containing metal layer arranged on the steel layer; and plural granular alloys which exist in an interface between the steel layer and the Al-containing metal layer, wherein, when a cutting-plane line of a surface of the Al-containing metal layer is defined as a contour curve and an approximation straight line of the contour curve is defined as a contour average straight line, a maximum point, whose distance from the contour average straight line is more than 10 μm, is absent on the contour curve, and wherein, when an equivalent sphere diameter of the granular alloys is x in units of μm and a thickness of the Al-containing metal layer is T in units of μm, the granular alloys satisfy x≦0.5T.

First claim

The invention claimed is:

1. A metal foil for a base material of a solar cell and an organic electroluminescence, the metal foil comprising:
a steel layer whose thickness is 10 to 200 μm;
an Al-containing metal layer arranged on the steel layer; and
plural granular alloys which exist in an interface between the steel layer and the Al-containing metal layer,
wherein a contour curve lacks any maximum points, which are convex toward a surface of the Al-containing metal layer and whose distances from a contour average straight line are more than 10 μm, wherein the contour curve is defined as a cutting-plane line of said surface of the Al-containing metal layer, which appears on a cross-section of the metal foil that is planarly cut along a normal direction so that an observed section is a transverse direction perpendicular to a rolling direction, and wherein the contour average straight line is defined as an approximation straight line of the contour curve, which appears on the cross-section, and
wherein 95% or more of all the plural granular alloys satisfy a following Formula 1:
x≦ 0.5 T   (Formula 1),

wherein x represents an equivalent sphere diameter of each of the plural granular alloys, in units of μm, and T represents a thickness of the Al-containing metal layer, in units of μm.

2. The metal foil according to claim 1 ,
wherein an interface curve of the steel layer, which corresponds to an interface average straight line having a length of 100 μm, contains at least one extremal point,
wherein the interface curve is defined as a cutting-plane line of the interface of the steel layer, which appears on the cross-section, wherein the interface average straight line is defined as an approximation straight line of the interface curve, which appears on the cross-section,
and, wherein the extremal point is defined as a point, which has a distance of more than 0.5 μm from the interface average straight line, on the interface curve.

3. The metal foil according to claim 1 ,
wherein
an average interval y is 100 μm or less,

wherein y is defined as an average interval between the granular alloys having an equivalent sphere diameter of 1.5 μm or more, and is measured in units of μm.

4. The metal foil according to claim 3 ,
wherein
an average diameter x ave and said average interval y satisfy following formulae 2 and 3:
0.06< x ave 2 /y   (Formula 2),

x ave <y   (Formula 3),

wherein x ave is defined as an average of the equivalent sphere diameter of the plural granular alloys, in units of μm.

5. The metal foil according to claim 1 , wherein the thickness of the Al-containing metal layer is 0.1 to 30 μm.

6. The metal foil according to claim 1 , further comprising an AlN layer whose thickness is 0.01 to 0.08 μm or an Al 2 O 3 layer whose thickness is 0.01 to 50 μm on the Al-containing metal layer.

7. The metal foil according to claim 1 , further comprising a Cr layer whose thickness is 0.1 to 8 μm or a Ni layer whose thickness is 0.1 to 8 μm on the Al-containing metal layer.

8. The metal foil according to claim 1 , further comprising at least a film selected from a sol-gel layer and a lamination layer on the Al-containing metal layer.

9. A producing method of the metal foil for the base material of the solar cell and the organic electroluminescence according to any one of claims 1 to 5 , the producing method comprising:
a first rolling process of rolling a steel sheet to a thickness of 200 to 500 μm;
a coating process of coating the steel sheet after the rolling process by using a coating bath containing 60 to 100 mass % of Al, 0 to 15 mass % of Si, and 0 to 40 mass % of Cu; and
a second rolling process of cold-rolling the steel sheet after the coating process by using a rolling mill equipped with plural backup rolls so that a cumulative rolling reduction is 50% or more.

10. The producing method of the metal foil according to claim 9 , wherein the coating bath containing Al for the coating process has a composition in which each element is within a range of plus or minus 5 mass % on the basis of a composition which is 68.2 mass % of Al, 4.7 mass % of Si, and 27.1 mass % of Cu or a composition which is 68 mass % of Al and 32 mass % of Cu.

11. The producing method of the metal foil according to claim 9 , wherein, in the second rolling process, a cold-rolling of at least 3 passes or more is conducted, a rolling reduction of a second pass is larger than that of a first pass, a rolling reduction of a third pass is smaller than that of the second pass, and a rolling reduction after the third pass is smaller than the rolling reduction of the third pass.

12. The producing method of the metal foil according to claim 9 , wherein, in the second rolling process, a reverse rolling is conducted so that the rolling direction of the steel sheet is reversed between each pass.

13. The producing method of the metal foil according to claim 9 , wherein, in the second rolling process, a rolling roll having a surface roughness Ra of 200 μm or less which is a mirror finished surface is used.

14. The producing method of the metal foil according to claim 9 , further comprising a skin-pass rolling process of bright-finished rolling the steel sheet after the second rolling process by using a rolling roll having a surface roughness Ra of 1 μm or less which is a mirror finished surface.

15. The producing method of the metal foil according to claim 9 , further comprising a heating process of heating the steel sheet after the second rolling process in a temperature range of 500 to 600° C. for 1 hour to 10 hours under an inert gas atmosphere containing an ammonia or a hydrazine of 10 volume %±2 volume %.

16. The producing method of the metal foil according to claim 9 , further comprising an anodizing process of anodizing the steel sheet after the second rolling process by using at least one selected from a sulfuric acid alumite, an oxalic acid alumite, or a chromic acid alumite.

17. The producing method of the metal foil according to claim 9 , further comprising an electrocoating process of forming a Cr layer or a Ni layer on the steel sheet after the second rolling process.

18. The producing method of the metal foil according to claim 9 , further comprising a film-forming process of forming at least a film selected from a sol-gel layer and a lamination layer on the steel sheet after the second rolling process.

19. The metal foil according to claim 1 ,
wherein an interface curve of the steel layer, which corresponds to an interface average straight line having a length of 100 μm, contains at least 6 extremal points,
wherein the interface curve is defined as a cutting-plane line of the interface of the steel layer, which appears on the cross-section, wherein the interface average straight line is defined as an approximation straight line of the interface curve, which appears on the cross-section,
and, wherein each point of the extremal points is defined as a point, which has a distance of more than 0.5 μm from the interface average straight line, on the interface curve.

20. The metal foil according to claim 1 ,
wherein an average interval y is 8 μm or more,
wherein y is defined as an average interval between the granular alloys having an equivalent sphere diameter of 1.5 μm or more, and is measured in units of μm.

Assignees

• Kobayashi Takayuki
• Terashima Shinichi
• Tanaka Masamoto
• Fujishima Masami
• Kurosaki Masao
• Maki Jun
• Suda Hideaki
• Nagasaki Shuji
• Nippon Steel & Sumikin Mat Co
• Nippon Steel & Sumitomo Metal Corp

Inventors

• Kobayashi Takayuki
• Terashima Shinichi
• Tanaka Masamoto
• Fujishima Masami
• Kurosaki Masao
• Maki Jun
• Suda Hideaki
• Nagasaki Shuji

Classifications

• Y10T428/12049

  Nonmetal component · CPC title

• Y02E10/541

  CuInSe2 material PV cells · CPC title

• H01L31/03926

  Electricity · mapped topic

• C23C2/12

  Aluminium or alloys based thereon · CPC title

• B21D39/00

  Application of procedures in order to connect objects or parts, e.g. coating with sheet metal otherwise than by plating ({joining mitred profiles B21D53/745; } riveting B21J; uniting components by forging or pressing to form integral members B21K25/00; welding B23K; press-fitting, force-fitting, or shrinking in general B23P11/00, B21D19/00; by adhesives F16B11/00 {; Connections as such F16L, F16B}); Tube expanders · CPC title