US3268358A - Diffusion cladding - Google Patents

Diffusion cladding Download PDF

Info

Publication number
US3268358A
US3268358A US218128A US21812862A US3268358A US 3268358 A US3268358 A US 3268358A US 218128 A US218128 A US 218128A US 21812862 A US21812862 A US 21812862A US 3268358 A US3268358 A US 3268358A
Authority
US
United States
Prior art keywords
zinc
base
aluminous
metal
diffusion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US218128A
Inventor
Marvin R Bothwell
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dow Chemical Co
Original Assignee
Dow Chemical Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dow Chemical Co filed Critical Dow Chemical Co
Priority to US218128A priority Critical patent/US3268358A/en
Priority to US509465A priority patent/US3390970A/en
Application granted granted Critical
Publication of US3268358A publication Critical patent/US3268358A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
    • C23C10/28—Solid state diffusion of only metal elements or silicon into metallic material surfaces using solids, e.g. powders, pastes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00—Stock material or miscellaneous articles
    • Y10S428/922—Static electricity metal bleed-off metallic stock
    • Y10S428/9265—Special properties
    • Y10S428/933—Sacrificial component
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00—Stock material or miscellaneous articles
    • Y10S428/922—Static electricity metal bleed-off metallic stock
    • Y10S428/9335—Product by special process
    • Y10S428/941—Solid state alloying, e.g. diffusion, to disappearance of an original layer
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12458—All metal or with adjacent metals having composition, density, or hardness gradient
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12736—Al-base component
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12771—Transition metal-base component
    • Y10T428/12785—Group IIB metal-base component
    • Y10T428/12792—Zn-base component

Definitions

  • This invention relates to sacrificial cladding of metals and is more particularly concerned with a process of cladding aluminous base metals by diffusion of zinc metal on and into the surface of the base metal.
  • aluminous base metals are metallurgically and laminarly clad with other aluminous metals containing various additive metals such as silver, cadmium, platinum, barium, bismuth, tin, and zinc sufficient in concentration to impart to the cladding layer a more active potential than that of the core metal so as to direct sacrificial corrosive attack to the cladding in preference to the core.
  • additive metals such as silver, cadmium, platinum, barium, bismuth, tin, and zinc
  • aluminous base metals pertains to metals containing predominantly aluminum.
  • the term thus includes elemental aluminum and the aluminum base alloys.
  • reference in this specification to zinc for initial coating purposes refers to metals consisting predominantly of zinc, and also refers to compounds containing zinc which are reducible to zinc metal by the aluminum during the diffusion heat treatment.
  • a further object is to provide a process whereby the zinc may be diffused into the surface of the base metal with little or no impairment of the physical properties of the base article.
  • a related object is to provide aluminous base metal articles having a protective diffused zinc surface the electrode potential of which is greater than that of the aluminous base metal.
  • This invention is based upon the discovery that the surface of an aluminous base metal can be given a substantially greater electrode potential than the base by depositing on the surface thereof a coating consisting essentially of zinc metal and diffusing such coating into the surface of the base by heat treating the coated article, thereby providing a zinc enriched surface and composition gradient such that when placed in a corroding atmosphere cathodic protection results in that galvanic attack is directed to the diffused zinc enriched surface in preference to the aluminous base. Diffusion cladding under the invention in this manner is accomplished without serious impairment of the physical properties of the base article.
  • any aluminous base metal 3,268,358 Patented August 23, 1966 configuration is coated with zinc metal or alloy thereof by any one of various methods of deposition known to the art so as to provide an initial zinc coating of about 0.l0 mg./cm. to about 10.0 mg./cm.
  • the coating is then diffused into the surface of the base by heat treating at a temperature within the range from about 500 F. to about 1100 F. for about 0.1 to about hours.
  • the heat treatment is to be sufficient to accomplish at least a 0.001 inch penetration having at least a 0.5 percent zince concentration at said depth penetration.
  • the invention is practiced with the deposited coating of Zinc to be diffused being approximately 0.8 mg./cm. with heat treatment to effect diffusion being carried out at about 970 F. for about 5 hours.
  • the application of heat treatment time and temperature to effect diffusion directly depends upon the initial zinc concentration per unit area of base metal surface, that is, an initial concentration in the lower limits of the aforementioned coating range of 0.10 mg./cm. to 10.0 mg./crn. will require a lower heat treatment temperature and time to achieve optimum results, whereas, a heavy initial coating within said range will require a greater temperature and time.
  • the time and temperature combination in relation to one another is inverse, that is, heat treating at higher temperatures will require less time to effect proper diffusion of a given initial zinc coating than with lower temperatures.
  • One method of deposition found to be particularly satisfactory to obtain the initial zinc coating for diffusion is a two step Zinc immersion process whereby the aluminous base metal is first activated in a dilute aqueous NaOH solution and then immersion plated with zinc by simple displacement in an alkaline zincate solution.
  • Other methods of deposition known to the art are also applicable to the invention to obtain the initial zinc coating, such as metal spraying, electrodeposition, and mechanical plating with metal powder using abrasives.
  • Table I indicates preferable, but not limiting, combinations of initial zinc coating weights to heat treatment ice
  • This invention provides a simple and economically practical process whereby all or any desired part of the exposed surfaces of any configuration of aluminous base metal articles can be given an electrode potential greater than that of the underlying base by enriching said surface by diffusion of zinc to provide a sacrificial zinc diffused surface which in the presence of a corroding medium will preferentially bear corrosive attack.
  • the process causes, and the product shows, little or no impairment of the physical properties of the core metal.
  • a method of producing non-laminar preferentially sacrificial surface metal on aluminous base articles which comprises applying a superficial coating of zinc in amount of about 0.8 mg./cm. on the aluminous base surface to be protected, and heat treating the so-coated article at 3 about 970 F. for about 5 hours to eifect diffusion of the zinc into the a luminous base, establishing a gradient in Zinc concentration from the surface into the aluminous base.
  • a method of producing non-laminar, preferentially sacrificial surface metal on aluminous base articles which comprises: providing an alumiuous base surface to be protected; applying onto said aluminous base surface a superficial coating of zinc to a per unit area concentration of from about 0.10 to about 10.0 mg./cm. heat treating the so-coated article at a temperature of from about 500 F. to about 1100 F.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)

Description

United States Patent Delaware No Drawing. Filed Aug. 20, 1962, Ser. No. 218,128 2 Claims. (61. 117-131) This invention relates to sacrificial cladding of metals and is more particularly concerned with a process of cladding aluminous base metals by diffusion of zinc metal on and into the surface of the base metal.
Under present art aluminous base metals are metallurgically and laminarly clad with other aluminous metals containing various additive metals such as silver, cadmium, platinum, barium, bismuth, tin, and zinc sufficient in concentration to impart to the cladding layer a more active potential than that of the core metal so as to direct sacrificial corrosive attack to the cladding in preference to the core. In practice however, metallurgical and laminar cladding is economically or technically limited to sheet or plate core metal, and is comparatively expensive when applied to tubular goods and cannot be applied to irregular configurations such as castings.
In view of the limitation in metallurgical and laminar cladding techniques there is a need in the art for a simple and economical process whereby aluminous base metals of substantially any irregular configuration, the surfaces of which, can be processed to obtain a sacrificial non-laminar cladding of a higher electrode potential than that of the base metal which will, therefore, corrode in preference to the base when in contact with a corroding medium and prevent pitting and other type corrosion of the base metal.
Further reference in this specification to aluminous base metals pertains to metals containing predominantly aluminum. The term thus includes elemental aluminum and the aluminum base alloys. Also, reference in this specification to zinc for initial coating purposes refers to metals consisting predominantly of zinc, and also refers to compounds containing zinc which are reducible to zinc metal by the aluminum during the diffusion heat treatment.
It is the object of this invention to provide a method whereby zinc is diffused into the surface of an aluminous metal base rendering a greater electrode potential to said aluminum-zinc surface gradient so that any corrosive attack will be preferentially directed to the diffused zinc enriched surface rather than to the base.
It is also the object of this invention to provide an economical process whereby zinc can be diffused into the surface of an aluminous base metal of any configuration.
A further object is to provide a process whereby the zinc may be diffused into the surface of the base metal with little or no impairment of the physical properties of the base article. A related object is to provide aluminous base metal articles having a protective diffused zinc surface the electrode potential of which is greater than that of the aluminous base metal.
This invention is based upon the discovery that the surface of an aluminous base metal can be given a substantially greater electrode potential than the base by depositing on the surface thereof a coating consisting essentially of zinc metal and diffusing such coating into the surface of the base by heat treating the coated article, thereby providing a zinc enriched surface and composition gradient such that when placed in a corroding atmosphere cathodic protection results in that galvanic attack is directed to the diffused zinc enriched surface in preference to the aluminous base. Diffusion cladding under the invention in this manner is accomplished without serious impairment of the physical properties of the base article.
In practicing the invention any aluminous base metal 3,268,358 Patented August 23, 1966 configuration is coated with zinc metal or alloy thereof by any one of various methods of deposition known to the art so as to provide an initial zinc coating of about 0.l0 mg./cm. to about 10.0 mg./cm. The coating is then diffused into the surface of the base by heat treating at a temperature within the range from about 500 F. to about 1100 F. for about 0.1 to about hours. In any case, the heat treatment is to be sufficient to accomplish at least a 0.001 inch penetration having at least a 0.5 percent zince concentration at said depth penetration. Preferably, the invention is practiced with the deposited coating of Zinc to be diffused being approximately 0.8 mg./cm. with heat treatment to effect diffusion being carried out at about 970 F. for about 5 hours.
The application of heat treatment time and temperature to effect diffusion directly depends upon the initial zinc concentration per unit area of base metal surface, that is, an initial concentration in the lower limits of the aforementioned coating range of 0.10 mg./cm. to 10.0 mg./crn. will require a lower heat treatment temperature and time to achieve optimum results, whereas, a heavy initial coating within said range will require a greater temperature and time. The time and temperature combination in relation to one another however, is inverse, that is, heat treating at higher temperatures will require less time to effect proper diffusion of a given initial zinc coating than with lower temperatures.
One method of deposition found to be particularly satisfactory to obtain the initial zinc coating for diffusion is a two step Zinc immersion process whereby the aluminous base metal is first activated in a dilute aqueous NaOH solution and then immersion plated with zinc by simple displacement in an alkaline zincate solution. Other methods of deposition known to the art are also applicable to the invention to obtain the initial zinc coating, such as metal spraying, electrodeposition, and mechanical plating with metal powder using abrasives.
Table I indicates preferable, but not limiting, combinations of initial zinc coating weights to heat treatment ice This invention provides a simple and economically practical process whereby all or any desired part of the exposed surfaces of any configuration of aluminous base metal articles can be given an electrode potential greater than that of the underlying base by enriching said surface by diffusion of zinc to provide a sacrificial zinc diffused surface which in the presence of a corroding medium will preferentially bear corrosive attack. In addition, the process causes, and the product shows, little or no impairment of the physical properties of the core metal.
I claim:
, 1. A method of producing non-laminar preferentially sacrificial surface metal on aluminous base articles, which comprises applying a superficial coating of zinc in amount of about 0.8 mg./cm. on the aluminous base surface to be protected, and heat treating the so-coated article at 3 about 970 F. for about 5 hours to eifect diffusion of the zinc into the a luminous base, establishing a gradient in Zinc concentration from the surface into the aluminous base.
2. A method of producing non-laminar, preferentially sacrificial surface metal on aluminous base articles which comprises: providing an alumiuous base surface to be protected; applying onto said aluminous base surface a superficial coating of zinc to a per unit area concentration of from about 0.10 to about 10.0 mg./cm. heat treating the so-coated article at a temperature of from about 500 F. to about 1100 F. for a duration of from about 0.1 to about 100 hours to eflYect difiusion of the zinc into the aluminous base; and establishing a zinc-aluminous gradient by diffusion of said zinc from the surface into the alurniuous base, said zinc-aluminous gradient extending to a depth of at least about 0.001 inch into said aluminous base.
References Cited by the Examiner UNITED STATES PATENTS ALFRED L. LEAVITT, Primary Examiner.
RICHARD D. NEVIUS, MURRAY KATZ, Examiners. R. S. KENDALL, I. P. MCINTOSH, Assistant Examiners.

Claims (1)

1. A METHOD OF PRODUCING NON-LAMINAR PREFERENTIALLY SACRIFICIAL SURFACE METAL ON ALUMINOUS BASE ARTICLES, WHICH COMPRISES APPLYING A SUPERFICIAL COATING OF ZINC IN AMOUNT OF ABOUT 0.8 MG./CM.2 ON THE ALUMINOUS BASE SURFACE TO BE PROTECTED, AND HEAT TREATING THE SO-COATED ARTICLE AT ABOUT 970*F. FOR ABOUT 5 HOURS TO EFFECT DIFFUSION OF THE ZINC INTO THE ALUMINOUS BASE, ESTABLISHING A GRADIENT IN ZINC CONCENTRATION FROM THE SURFACE INTO THE ALUMINOUS BASE.
US218128A 1962-08-20 1962-08-20 Diffusion cladding Expired - Lifetime US3268358A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US218128A US3268358A (en) 1962-08-20 1962-08-20 Diffusion cladding
US509465A US3390970A (en) 1962-08-20 1965-10-21 Diffusion cladding aluminum article with a diffused zinc coat

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US218128A US3268358A (en) 1962-08-20 1962-08-20 Diffusion cladding

Publications (1)

Publication Number Publication Date
US3268358A true US3268358A (en) 1966-08-23

Family

ID=22813853

Family Applications (1)

Application Number Title Priority Date Filing Date
US218128A Expired - Lifetime US3268358A (en) 1962-08-20 1962-08-20 Diffusion cladding

Country Status (1)

Country Link
US (1) US3268358A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3390970A (en) * 1962-08-20 1968-07-02 Dow Chemical Co Diffusion cladding aluminum article with a diffused zinc coat
WO2013116199A1 (en) * 2012-02-01 2013-08-08 United Technologies Corporation Surface implantation for corrosion protection of aluminum components
US20150203951A1 (en) * 2012-12-12 2015-07-23 Kwik-Coat (Aust) Pty Ltd Alloy coated workpieces
JP2017008356A (en) * 2015-06-19 2017-01-12 三菱アルミニウム株式会社 Aluminum alloy tube for heat exchanger and production method for the same, and heat exchanger core
TWI575085B (en) * 2014-04-09 2017-03-21 維克塗層（澳大利亞）有限公司 Alloy coated workpieces

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1944227A (en) * 1931-09-11 1934-01-23 Votaw S Durbin Galvanized malleable iron and method of producing same
US2682702A (en) * 1949-04-06 1954-07-06 Ohio Commw Eng Co Carbonyl metal plated product
US2741018A (en) * 1947-07-16 1956-04-10 Clevite Corp Bearing
US2987814A (en) * 1957-01-25 1961-06-13 Reynolds Metals Co Process and product of zinc and aluminum lamination
US2991197A (en) * 1959-10-30 1961-07-04 George A Sandoz Method for coating columbium and alloys thereof
US3063145A (en) * 1957-08-15 1962-11-13 Bell Telephone Labor Inc Soldering of aluminum

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1944227A (en) * 1931-09-11 1934-01-23 Votaw S Durbin Galvanized malleable iron and method of producing same
US2741018A (en) * 1947-07-16 1956-04-10 Clevite Corp Bearing
US2682702A (en) * 1949-04-06 1954-07-06 Ohio Commw Eng Co Carbonyl metal plated product
US2987814A (en) * 1957-01-25 1961-06-13 Reynolds Metals Co Process and product of zinc and aluminum lamination
US3063145A (en) * 1957-08-15 1962-11-13 Bell Telephone Labor Inc Soldering of aluminum
US2991197A (en) * 1959-10-30 1961-07-04 George A Sandoz Method for coating columbium and alloys thereof

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3390970A (en) * 1962-08-20 1968-07-02 Dow Chemical Co Diffusion cladding aluminum article with a diffused zinc coat
WO2013116199A1 (en) * 2012-02-01 2013-08-08 United Technologies Corporation Surface implantation for corrosion protection of aluminum components
US20150203951A1 (en) * 2012-12-12 2015-07-23 Kwik-Coat (Aust) Pty Ltd Alloy coated workpieces
US9885103B2 (en) * 2012-12-12 2018-02-06 Kwik-Coat (Aust) Pty Ltd Alloy coated workpieces
TWI575085B (en) * 2014-04-09 2017-03-21 維克塗層（澳大利亞）有限公司 Alloy coated workpieces
JP2017008356A (en) * 2015-06-19 2017-01-12 三菱アルミニウム株式会社 Aluminum alloy tube for heat exchanger and production method for the same, and heat exchanger core

Similar Documents

Publication Publication Date Title
JPS6096786A (en) Electroplated product and its production
US3268358A (en) Diffusion cladding
US3078555A (en) Method of coating a galvanized article with iron and article produced thereby
US2381778A (en) Process of producing protected metal articles
US3762883A (en) Coated steel article
JPH04147953A (en) Production of galvannealed steel sheet
US2323890A (en) Coated wire
US3897222A (en) Protective coating for ferrous metals
US2894885A (en) Method of applying copper coatings to uranium
JPH03138389A (en) Zn-mg alloy plated steel sheet having excellent plating adhesion and corrosion resistance and its production
JPH0452284A (en) High corrosion-resistant two-layer plated steel sheet and its production
US4036600A (en) Steel substrate electroplated with Al powder dispersed in Zn
US3390970A (en) Diffusion cladding aluminum article with a diffused zinc coat
US2788289A (en) Method of forming protective coatings for molybdenum and molybdenum-base alloys
US4170525A (en) Process for plating a composite structure
US3364057A (en) Metal hydroxide intermediate coating for metal
JPH03229846A (en) Galvanized material and galvanizing method
US2176066A (en) Tin-coated object
US3325282A (en) Method of forming a zinc-aluminum coating on a ferrous base
US3026606A (en) Hot-dip aluminum coating
US3911177A (en) Process for preparing steel for enameling
US3726705A (en) Process for galvanizing a ferrous metal article
JPS5767170A (en) Manufacture of boride coated metal
JP3135818B2 (en) Manufacturing method of zinc-tin alloy plated steel sheet
US2359813A (en) Protective covering for welding rods