Method for treating a surface such as a metal surface and producing products embodying such including lithoplate

• US 5,481,084 A
• Filed: 10/08/1993
• Issued: 01/02/1996
• Est. Priority Date: 03/18/1991
• Status: Expired due to Fees

• Current Assignee: Alcoa Incorporated (Howmet Aerospace, Inc.)
• Original Assignee: Aluminum Company of America (Howmet Aerospace, Inc.)
• Inventors: Patrick, Edward P., Pajerski, A. Victor
• Primary Examiner(s): Shaw, Clifford C.
• Application Number:
  US08/134,165
• Time in Patent Office: 816 Days
• Field of Search: 219/68, 219/69.1, 219/69.11, 219/123, 219/125.12, 219/137 R, 148/222, 148/224, 148/524, 148/526, 148/565, 148/566, 427/455, 427/534
• US Class Current: 219/123
• CPC Class Codes: B21B 2001/383 Cladded or coated products
• CPC Class Codes: B22D 11/008 of clad ingots, i.e. the molten metal being cast against a continuous strip forming part of the cast product
• CPC Class Codes: B41N 1/083 made of aluminium or aluminium alloys or having such surface layers B41N1/086 takes precedence
• CPC Class Codes: B41N 3/032 Graining by laser, arc or plasma means
• CPC Class Codes: F28F 13/18 by applying coatings, e.g. radiation-absorbing, radiation-reflecting; by surface treatment, e.g. polishing
• CPC Class Codes: F28F 2245/02 hydrophilic
• CPC Class Codes: F28F 2245/04 hydrophobic

Abstract

Substantial surface areas can be treated by continuously magnetically moving an electric arc around a general loop direction such as a circle, ellipse or oval and moving the surface so that the arc treats a substantial surface area. The arc treatment can be used to clean or increase surface area, or both, and a reactant or treatment agent can be brought to the arc contact site to alter the surface treated with the arc. Auxiliary treatments for the surface can precede or follow the arc treatment, or both. The invention produces very desirable surface properties including a mild roughness or matte condition suitable even for critical applications such as aluminum lithoplate. Other surface characteristics can include one or more of: capillarity, adhesion, emissivity, stable oxide, paintability, and others. Applications and advantages are believed to include lithoplate, hydrophilic heat exchanger finstock, capacitor foil, can sheet, venetian blind stock, adhesive bonded laminates and other bonded structural materials or structures, welding rod, aluminum brazing sheet, interrogatable strips for optical control instruments, enhanced, high current contacts, improved, controlled or differential friction characteristics for forming and shaping, automotive and other sheet, hot roll bonding, galvanizing and zinc coating of steel, texturing mill rolls, pretreatment for thermal spray treatments, organic coating adhesion, improved paint hiding performance, prosthetics, biohost or catalyst support and others. The process is applicable to aluminum, steel and other metals and other materials capable of carrying current sufficiently to maintain an electric arc.

Claims

1. A method of treating metal sheet for lithoplate application having a substantial surface to which a substantially stable electric arc can be applied comprising continuously moving an electric arc on said surface by magnetic impulsion around a loop periphery path established by a loop electrode, the loop of which is in arc passing relationship with said surface and effecting relative movement between one or more such electric arcs and said surface in such a manner as to contact a major portion of said surface and increase its surface area.

2. A method of treating an object having a substantial surface to which a substantially stable electric arc can be applied comprising continuously moving an electric arc on said surface by magnetic impulsion around a loop periphery path established by a loop electrode, the loop of which is in arc passing relationship with said surface and effecting relative movement between one or more such electric arcs and said surface in such a manner as to contact a major portion of said surface and increase its surface area.

3. The method according to claim 2 wherein said loop is substantially oval or elliptical.

4. The method according to claim 2 wherein said treatment heats at least a portion of said object sufficiently to affect its internal structure.

5. The method according to claim 2 wherein a reaction agent or treatment agent is brought into the arc site and reacted to alter said surface.

6. The method according to claim 2 wherein said object is a coilable strip or sheet.

7. The method according to claim 2 wherein said object is a rigid plate.

8. The method according to claim 2 wherein said object is a thick metal stock for hot rolling.

9. The method according to claim 3 wherein said object is a thick metal stock for hot rolling and wherein a cladding is bonded by hot roll bonding to the surface treated according to claim 2.

10. The method according to claim 2 wherein said surface is subsequently chemically treated.

11. The method according to claim 2 wherein the surface treated is negative and the electrode is positive.

12. The method according to claim 2 wherein the surface treated is positive and the electrode is negative.

13. The method according to claim 2 wherein said surface treated is at least 100 contiguous square feet having a minor dimension not less than 6 inches wide.

14. The method according to claim 2 wherein said surface treated is a contiguous area of at least 50 square feet, the minor dimension of which is not less than 6 inches.

15. The method of claim 2 wherein said loop is substantially circular.

16. The method of claim 2 wherein said relative movement is effected by moving said electrode in relation to said object so as to form a plurality of adjacent pass lines.

17. The method of claim 2 wherein said arc is directed along a substantially circular path.

18. The method of claim 2 wherein said electrode loop is substantially circular and a plurality of said circular loop electrodes are positioned across the width of a moving surface being treated, said moving surface moving in a direction substantially transverse to its width.

19. The method of claim 2 wherein an electrode loop is elongate oval or elliptical and its major axis traverses a substantial part of the width of said surface and said surface moves transverse to said elongate major axis of said oval or elliptical loop.

20. The method of claim 2 in which a plurality of such arcs are passed to said surface.

21. The method of claim 2 in which at least one permanent magnet is used in magnetically moving said arc.

22. The method of claim 2 in which at least one electromagnet is used in magnetically moving said arc.

23. The method of claim 2 in which said arc is directed along an oval or elliptical path.

24. The method of claim 2 which includes moving an electrode back and forth across a substantial portion of said surface as the arc travels around an oval or elliptical path so as to contact an extensive area of said surface with said arc.

25. The method of claim 2 which includes directing said arc in multiple passes across the same portion of the width of moving metal surface.

26. The method of claim 2 in which said surface comprises aluminum or aluminum alloy and said surface so treated is exposed to a media containing water to produce a surface containing boehmite.

27. The method of claim 2 in which said surface comprises aluminum or aluminum alloy and a portion of the surface so treated is anodized.

28. A method of increasing the surface area of a metallic surface using an electric arc, said method comprising:

(a) moving metal having a width and length in a first direction which is generally parallel to said length; and

(b) continuously moving an electric arc on said surface by magnetic impulsion around an oval or elliptical loop periphery path established by an oval or elliptical loop electrode, the loop of which is in arc passing relationship with said surface, the loop extending across a substantial portion of the width of said metal, and effecting relative movement between one or more such electric arcs and said surface in such a manner as to contact a major portion of said surface.

29. A method of increasing the surface area of a metal surface comprising:

(a) moving a band of metal having said surface, said surface having a width and a length, in a direction parallel to its length; and

(b) continuously moving an electric arc on said surface by magnetic impulsion around a loop periphery path established by a loop electrode, the loop of which is in arc passing relationship with said surface so as to contact an extensive area of said surface.

30. The method according to claim 29 for producing lithoplate.

31. A method of increasing the surface area of a metal surface comprising:

(a) moving a band of said metal having said surface, said surface having a width and a length, in a direction parallel to its length; and

(b) conducting a plurality of electric arcs to said moving surface at least a plurality of such arcs being continuously moved on said surface by electromagnetic impulsion around loop periphery paths established by a plurality of loop electrodes, the loops of which are in arc passing relationship with said surface so as to contact an extensive area of said surface.

32. The method according to claim 31 for producing lithoplate.

33. The method according to claim 31 wherein a plurality of said loop electrodes are circular loops.

34. A method of increasing the surface area of a metal band surface comprising:

(a) moving a band of said metal having a width and a length in a direction parallel to its length; and

(b) conducting a plurality of electric arcs to said moving metal band surface, a plurality of such arcs being continuously moved on said surface by electromagnetic impulsion around a plurality of oval or elliptical loop periphery paths established by oval or elliptical loop electrodes, the loops of which are in arc passing relationship with said surface, the loops extending across a substantial portion of the width of said metal so as to cause said arcs to contact an extensive area of said metal.

35. A method of increasing the surface area of the surface of aluminum metal using an electric arc, said method comprising:

(a) moving aluminum metal having a width and length in a first direction which is generally parallel to said length;

(b) conducting an electric arc between at least one loop electrode and a surface of said metal passing adjacent said electrode; and

(c) magnetically moving said arc along at least one said loop electrode so as to contact a substantial portion of said width of said moving metal with said arc so as to contact an extensive area of said surface with said arc, said arc following a path generally defined by said loop shape of said electrode.

36. The method of claim 35 in which recitation (c) includes:

magnetically moving said arc across a substantial portion of said width of said metal so as to contact an extensive area of said metal.

37. The method of claim 35 in which recitation (c) includes:

using at least one permanent magnet to move said arc across a substantial portion of said width of said metal so as to contact an extensive area of said metal.

38. The method of claim 35 in which recitation (c) includes:

using at least one electromagnet to move said arc across a substantial portion of said width of said metal so as to contact an extensive area of said metal.

39. The method of increasing the surface area of a metal sheet or foil product comprising conducting one or more electric arcs to a major surface of said sheet or foil and effecting relative movement between said arc and said surface including continuously moving an electric arc on said surface by electromagnetic impulsion around a loop periphery path established by a loop electrode, the loop of which is in arc passing relationship with said surface in such a manner as to contact an extensive area of said surface.

40. The method according to claim 39 wherein a reaction agent or treatment agent is brought into the arc site and reacted to alter the surface.

41. A method of treating an object comprising conducting one or more electric arcs to a surface of said object including continuously moving an electric arc on said surface by magnetic impulsion around a loop periphery path established by a loop electrode, the loop of which is in arc passing relationship with said surface and effecting relative movement between one or more such electric arcs and said surface in such a manner as to contact a major portion of said surface and increase its surface area, and bringing a treatment agent into the arc site during arc contact with said surface to alter said surface.

42. The method according to claim 41 wherein a reaction agent or treatment agent is brought to the arc site as a fluid.

43. The method according to claim 41 wherein a reaction agent or treatment agent is brought to the arc site as a gas.

44. The method according to claim 41 wherein a reaction agent or treatment agent is brought to the arc site as a solid.

45. The method according to claim 41 wherein a reaction agent or treatment agent is present on the surface of said sheet prior to said treatment.

46. A method of treating a metallic surface of an object comprising continuously moving an electric arc on said surface by magnetic impulsion around a loop periphery path established by a loop electrode, the loop of which is in arc passing relationship with said surface and effecting relative movement between one or more such electric arcs and said surface in such a manner as to contact an extensive portion of said surface and increase its surface area.

47. The method according to claim 46 wherein said surface is a cylindrical surface and said arc is magnetically impelled generally circumferentially on said surface and substantially axial movement is provided between said arc and said cylindrical surface.

48. The method according to claim 47 wherein said arc is applied to an inside cylindrical surface.

49. The method according to claim 47 wherein said cylindrical surface is an outside cylindrical surface.

50. The method according to claim 46 wherein said surface is a planar surface.

51. The method according to claim 46 wherein said metallic object is coilable metal sheet.

52. The method according to claim 46 wherein said object is coilable aluminum or aluminum alloy sheet.

53. The method according to claim 46 wherein said object is ferrous sheet.

54. The method according to claim 46 wherein said object is aluminum or aluminum alloy sheet.

55. The method according to claim 46 wherein said object is ferrous sheet and said ferrous sheet is subsequently coated with material comprising zinc.

56. The method according to claim 46 wherein said object is thick plate.

57. The method according to claim 46 wherein said object is a metal ingot.

58. The method according to claim 46 wherein said surface is a metal surface that is then bonded to a second surface.

59. The method according to claim 46 wherein said surface is a metal surface that is bonded to another metal surface that has been treated according to claim 51.

60. The method according to claim 59 wherein said bonding is roll bonding.

61. The method according to claim 59 wherein the bonding is adhesive bonding.

62. The method according to claim 46 wherein said metallic object is container sheet for making into a formed or shaped container panel.

63. The method according to claim 46 wherein said metallic object is sheet for later forming or shaping into a vehicular member.

64. The method according to claim 63 wherein said sheet is provided with a conversion or other coating prior to being formed or shaped.

65. The method according to claim 63 wherein said sheet is shaped into a panel for a dual panel vehicular member and joined to another panel.

66. The method according to claim 65 wherein said sheet is first provided with a conversion or other coating before shaping.

67. The method according to claim 65 wherein said joining includes adhesive bonding or spot welding, or both.

68. The method according to claim 46 wherein said metallic object is appliance sheet that is made into an appliance panel.

69. The method according to claim 46 wherein said metallic object is venetian blind sheet that has a coating applied thereto.

70. The method according to claim 69 wherein said object is ferrous sheet and said ferrous sheet is subsequently coated with material comprising zinc.

71. The method according to claim 46 wherein said metallic object is sheet or foil for capacitors and wherein said increased surface is anodized.

72. The method according to claim 46 wherein said metal object is heat exchanger finstock sheet for incorporation into a heat exchanger having fins provided by said sheet.

73. The method according to claim 46 wherein said metallic object is a rolling mill roll and said surface is the rolling surface thereof.

74. The method according to claim 46 wherein said object is a sheet or plate layer for a structural laminate, said sheet or plate layer having at least one major surface thereof treated according to claim 46, said surface being spaced from another metal surface treated in accordance with claim 46, said surfaces being joined through an adhesive therebetween containing a reinforcing media in said laminate.

75. The method according to claim 74 wherein said structural laminate contains several of said metallic layers, at least some of said metallic layers being in aluminum or an alloy thereof.

76. The method according to claim 46 wherein said metal object is aluminum or aluminum alloy sheet that is made into a cathode in a zinc electrolysis cell.

77. The method according to claim 46 wherein said metallic object is steel sheet and wherein said surface treated according to claim 46 is coated with zinc by contact with molten media comprising zinc.

78. The method according to claim 46 wherein said metallic object is a metal sheet or plate wherein the method according to claim 46 is applied to a rolling surface thereof to provide an optically interrogatable matte surface band at or near the lateral edge of said rolling surface for optical rolling mill control instrumentation.

79. The method according to claim 46 wherein said arc is magnetically impelled at a speed of at least 50 feet per second.

80. The method according to claim 46 wherein said arc is magnetically impelled at a speed of at least 200 feet per second.

81. The method according to claim 46 wherein said arc is magnetically impelled at a speed of at least 400 feet per second.

82. The method according to claim 46 wherein said arc is magnetically impelled at a speed of at least 600 feet per second.

83. The method according to claim 46 wherein said arc is magnetically impelled at a speed of at least 1000 feet per second.

84. The method according to claim 46 wherein said arc is magnetically impelled at a speed of at least 2000 feet per second.

85. The method according to claim 46 wherein said arc is a d.c. arc with said electrode being the positive connection and said metallic object being connected to ground.

86. The method according to claim 46 wherein said arc is an alternating current arc.

87. The method according to claim 46 wherein an inert gas is provided at the arc site.

88. The method according to claim 46 wherein the arc site is not deliberately provided with gas from a site external to the arc site.

89. The method according to claim 46 wherein said arc is conducted in the presence of an atmosphere containing air.

90. The method according to claim 46 wherein said arc is conducted in the presence of an atmosphere containing oxygen.

91. The method according to claim 46 wherein no shielding gas is provided.

92. The method according to claim 46 wherein a gas is provided to the arc region, said gas comprising hydrogen and an inert gas.

93. The method according to claim 46 wherein a treatment agent is provided in the arc region.

94. The method according to claim 46 wherein a material is provided to the arc region, said material comprising one or more substances selected from the group consisting of nitrogen, ammonia, oxygen, organic nitrides, organic nitrates, diborane, boron halides, organic boron compounds, hydrocarbons, oxygen-containing hydrocarbons, or combinations thereof.

95. The method according to claim 46 wherein the arc region is provided with one or more substances from the group consisting of volatile metal compounds, metal halides, organometal complexes, metal hydrides, metal carbonyls and other metal bearing gases.

96. The method according to claim 46 wherein the arc site is provided with a treatment agent provided to the arc region as a liquid.

97. The method according to claim 46 wherein the arc site is provided with a treatment agent provided to the arc region as a solid.

98. The method according to either claim 96 or claim 97 wherein said agent is applied to said surface prior to treatment by said arc.

99. The method according to claim 46 wherein the means for providing said magnetically impelled arc comprise a channel-shaped magnetic core which is a permanent magnet.

100. The method according to claim 46 wherein the means for providing said arc include a channel-shaped magnetic core and electrical windings to produce electromagnetism at the core ends with the electrode projecting in the vicinity of said core ends.

101. The method according to claim 46 wherein said metallic object is provided as a catalyst support and a catalyst is applied thereto.

102. The method according to claim 46 wherein said metallic object is a prosthetic device and said surface is a tissue attaching surface.

103. The method according to claim 46 wherein said surface has an organic coating applied thereto.

104. The method according to claim 46 wherein said metallic object is for a heavy current electrical contact device and said surface is an electrical current contact surface for large electric currents.

105. The method according to claim 46 wherein said surface is a metal surface that is bonded to another metal surface.

106. The method according to claim 107 wherein said bonding is roll bonding.

107. The method according to claim 46 wherein said surface is bonded to another material which is metallic.

108. The method according to claim 46 wherein said surface is bonded to another material.