US1961030A - Process for protecting magnesium and its alloys against corrosion - Google Patents

Process for protecting magnesium and its alloys against corrosion Download PDF

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Publication number
US1961030A
US1961030A US607217A US60721732A US1961030A US 1961030 A US1961030 A US 1961030A US 607217 A US607217 A US 607217A US 60721732 A US60721732 A US 60721732A US 1961030 A US1961030 A US 1961030A
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United States
Prior art keywords
against corrosion
metal
magnesium
alloys against
protecting magnesium
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Expired - Lifetime
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US607217A
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Bengough Guy Dunstan
Whitby Lawrence
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IMP TRUST FOR ENCOURAGEMEN
IMPERIAL TRUST FOR ENCOURAGEMENT OF SCIENTIFIE AND INDUSTRIAL RESEARCH
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IMP TRUST FOR ENCOURAGEMEN
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    • 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
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
    • C23C22/48—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates
    • C23C22/57—Treatment of magnesium or alloys based thereon

Definitions

  • Our invention relates to the protection of magnesium and its alloys against corrosion and has for its object the better use of selenium and its compounds than has heretofore been achieved for 5 this purpose.
  • our invention we use an aqueous solution of selenious acid or of a soluble selenite to treat the magnesium or its alloys and obtain coatings containing selenium in its elemental and/ or combined forms.
  • Selenious acid solution gives the best results, but a solution of a soluble selenite, generally sodium selenite containing selenious acid or a salt or acid known to corrode magnesium, particularly sodium chloride, gives excellent protection.
  • Example 1 The metal to be protected is immersed in an aqueous solution of selenious acid per cent. strength at room temperature.
  • the time of immersion is from 5 seconds to 10 minutes according to the composition of the alloy; when the alloy known as electron alloy AZM (containing in.100 parts, Mg 925, Al 6.25, Zn 0.95, and Mn 0.30) is under treatment, five minutes is suitable.
  • the latter may be applied to the metal by a painting or spraying operation, for instance by rubbing the metal with cotton-wool soaked with the solution.
  • Example 2 To produce a comparatively thick and. porous coating suitable in cases where a coat of paint is subsequently to be applied, the metal is immersed in a bath of acidified aqueous sodium selenite solution, for instance a solution of sodium selenite of 6 per cent. strength to which has been added 6 per cent. by volume 0! syrupy phosphoric acid. This bath may be heated to 50 0.; the time of immersion is 1-5 minutes.
  • acidified aqueous sodium selenite solution for instance a solution of sodium selenite of 6 per cent. strength to which has been added 6 per cent. by volume 0! syrupy phosphoric acid.
  • This bath may be heated to 50 0.; the time of immersion is 1-5 minutes.
  • Example 3 The metal is immersed for 3 hours in an 8 per cent. aqueous solution of sodium selenite, containing about 3.2 per cent. selenious u acid and 0.1 per cent. sodium chloride and heated to about C.- C.
  • the protective action of the selenium coating may be improved if the coated metal is heated to about 170-225 0., for example in a mufile 65 furnace.
  • the operation is rapid and simple.
  • the film forms an excellent basis for the application of paints and greatly increases the protection they afiord.
  • a process of protecting magnesium and its alloys against corrosion which consists in treating the metal with an aqueous solution of selenious acid.
  • a process of protecting magnesium and its alloys against corrosion which consists in treating the metal with an aqueous solution of soluble selenite containing a material selected from the group consisting of phosphoric acid and selenious acid.

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  • Chemical & Material Sciences (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Treatment Of Metals (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
  • Paints Or Removers (AREA)

Description

Patented May 29 1934 UN TED STATES PATIENT OFFICE PROCESS FOR PROTECTING MAGNESIUM A D ITS ALLOYS AGAINST ooRRoSIoN Guy Dunstan Bengough and Lawrence Whitby,
Teddington, England, assignors to Imperial Trust for the Encouragement oi Scientific and Industrial Research, London, England No Drawing. Application April 23, 1932, Serial NO. 607,217. In Great Britain May 19, 1931 2 Claims. (01. 148-6) Our invention relates to the protection of magnesium and its alloys against corrosion and has for its object the better use of selenium and its compounds than has heretofore been achieved for 5 this purpose. In accordance with our invention we use an aqueous solution of selenious acid or of a soluble selenite to treat the magnesium or its alloys and obtain coatings containing selenium in its elemental and/ or combined forms. Selenious acid solution gives the best results, but a solution of a soluble selenite, generally sodium selenite containing selenious acid or a salt or acid known to corrode magnesium, particularly sodium chloride, gives excellent protection.
The following examples illustrate the invention:-
Example 1.-The metal to be protected is immersed in an aqueous solution of selenious acid per cent. strength at room temperature. The time of immersion is from 5 seconds to 10 minutes according to the composition of the alloy; when the alloy known as electron alloy AZM (containing in.100 parts, Mg 925, Al 6.25, Zn 0.95, and Mn 0.30) is under treatment, five minutes is suitable. A small addition of sodium chloride to the bath, such as 0.1-0.5 per cent., may improve the coating.
Insteadof immersing the metal in the solution, the latter may be applied to the metal by a painting or spraying operation, for instance by rubbing the metal with cotton-wool soaked with the solution.
Example 2.--To produce a comparatively thick and. porous coating suitable in cases where a coat of paint is subsequently to be applied, the metal is immersed in a bath of acidified aqueous sodium selenite solution, for instance a solution of sodium selenite of 6 per cent. strength to which has been added 6 per cent. by volume 0! syrupy phosphoric acid. This bath may be heated to 50 0.; the time of immersion is 1-5 minutes.
Example 3.The metal is immersed for 3 hours in an 8 per cent. aqueous solution of sodium selenite, containing about 3.2 per cent. selenious u acid and 0.1 per cent. sodium chloride and heated to about C.- C.
The protective action of the selenium coating may be improved if the coated metal is heated to about 170-225 0., for example in a mufile 65 furnace.
Special advantages of the invention are (1) that the film is self-healing to a limited extent in the presence of water, that is to say, if the film becomes slightly damaged it will re-form, at all 7 events partially, so that the metal remains protected to some extent, and (2) that the dimensional change of the metal during the process described in Example 1 is negligibly small.
The operation is rapid and simple.
The film forms an excellent basis for the application of paints and greatly increases the protection they afiord.
Having thus fully described the nature of the said invention and the best means we know of 80 carrying the same into. practical effect, what we claim as our invention is:-
1. A process of protecting magnesium and its alloys against corrosion which consists in treating the metal with an aqueous solution of selenious acid.
2. A process of protecting magnesium and its alloys against corrosion which consists in treating the metal with an aqueous solution of soluble selenite containing a material selected from the group consisting of phosphoric acid and selenious acid.
GUY DUNS'I'AN BENGOUGH. LAWRENCE WHI'ITBY.
US607217A 1931-05-19 1932-04-23 Process for protecting magnesium and its alloys against corrosion Expired - Lifetime US1961030A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB14724/31A GB378916A (en) 1931-05-19 1931-05-19 Improved process for protecting magnesium and its alloys against corrosion

Publications (1)

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US1961030A true US1961030A (en) 1934-05-29

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US (1) US1961030A (en)
DE (1) DE601521C (en)
FR (1) FR737082A (en)
GB (1) GB378916A (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2426173A (en) * 1942-12-01 1947-08-26 Standard Telephones Cables Ltd Selenium coating by immersion
US2438740A (en) * 1944-03-27 1948-03-30 Canadian Copper Refiners Ltd Method of protecting the surface of articles formed from a magnesium alloy
US2475945A (en) * 1946-09-21 1949-07-12 Canadian Copper Refiners Ltd Method of chemically coating metallic articles of aluminum or predominantly of aluminm and solution for use therein
US2475944A (en) * 1949-02-02 1949-07-12 Canadian Copper Refiners Ltd Process for protecting ferrous metal surfaces by coating and dipping solution for use therein
US2522474A (en) * 1942-07-02 1950-09-12 Battelle Memorial Institute Treatment of zinc surfaces
US2575388A (en) * 1947-01-06 1951-11-20 Vickers Inc Electrical rectifiers
US2692213A (en) * 1951-04-11 1954-10-19 Chicago Dev Corp Electrical conductor
US2878149A (en) * 1955-10-31 1959-03-17 Walter A Mason Product for effecting a cold chemical oxidation of copper and its alloys

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2522474A (en) * 1942-07-02 1950-09-12 Battelle Memorial Institute Treatment of zinc surfaces
US2426173A (en) * 1942-12-01 1947-08-26 Standard Telephones Cables Ltd Selenium coating by immersion
US2438740A (en) * 1944-03-27 1948-03-30 Canadian Copper Refiners Ltd Method of protecting the surface of articles formed from a magnesium alloy
US2475945A (en) * 1946-09-21 1949-07-12 Canadian Copper Refiners Ltd Method of chemically coating metallic articles of aluminum or predominantly of aluminm and solution for use therein
US2575388A (en) * 1947-01-06 1951-11-20 Vickers Inc Electrical rectifiers
US2475944A (en) * 1949-02-02 1949-07-12 Canadian Copper Refiners Ltd Process for protecting ferrous metal surfaces by coating and dipping solution for use therein
US2692213A (en) * 1951-04-11 1954-10-19 Chicago Dev Corp Electrical conductor
US2878149A (en) * 1955-10-31 1959-03-17 Walter A Mason Product for effecting a cold chemical oxidation of copper and its alloys

Also Published As

Publication number Publication date
FR737082A (en) 1932-12-06
DE601521C (en) 1934-08-17
GB378916A (en) 1932-08-19

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