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US2229236A - Process for the surface treatment of workpieces of magnesium and magnesium base alloys - Google Patents

Process for the surface treatment of workpieces of magnesium and magnesium base alloys Download PDF

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Publication number
US2229236A
US2229236A US293100A US29310039A US2229236A US 2229236 A US2229236 A US 2229236A US 293100 A US293100 A US 293100A US 29310039 A US29310039 A US 29310039A US 2229236 A US2229236 A US 2229236A
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Prior art keywords
magnesium
solution
base alloys
workpieces
water
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US293100A
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Beck Adolf
Siebel Gustav
Nachtigall Eduard
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MAGNESIUM DEV CORP
MAGNESIUM DEVELOPMENT Corp
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MAGNESIUM DEV CORP
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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

  • This invention relates to a process for the suriacetreatxfient of workpieces of magnesium and magnesium base alloys for thepurpose of forming a protective coating thereon.
  • corrosion resisting layers are produced on magnesium and magnesium base alloys by treating the metal with aqueous solutions of those salts of carboxylic acid or phenolates which react with magnesium to form substantially insoluble compoundsat temperatures in the vicinity of the boilingpoint of the solutions, but preferably at higher temperatures and in such case, under pressure.
  • alkali metal salts including the ammonium salts, of the saturated and unsaturated fatty; acids (including the iso-fatty acids) and oxy fatty acids. containing eight or more carbon atoms, and also. alkali metal salts, including the ammonium salts, of aromatic carboxylic acids having two or more carbon rings, andthe substitution products thereof, are particularly suitable for use in carrying out the present invention.
  • the use of the free fatty and oxy-fattyiacidsl also of the aromatic carboxylic acids themselves usually fails either because such acids form read: ily soluble magnesium salts or because they are not water-soluble.
  • solutions employed in carrying out the invention may, if desired, also contain other suitable solvents, such as ethanol, in addition to water.
  • the coatings produced in accordance with the present invention can be coloured by adding colouring substances to the solution employed for the treatment; the colouring substances may,
  • the hereindescribed process may also be applied to articles which have previously been subjected to a surface treatment, for example by a dipping process.
  • the thickness and quality of the coatings depend to a. certain extent, on the proportion of the alloying constituents contained in the magnesium, in the sense that the thickness of .the coating which can be built up varies inversely with the content of alloying constituents
  • the quality of the layer is largely independent of the concentration of the solutions employed.
  • aqueous solution oi! sulphoricinoleate Teurkey-red oil
  • a sheet of an alloy containing 6% of aluminium, 1% of zinc, remainder magnesium is heated at 180 C. for 15 minutes in an autoclave in a 5% aqueous solution or potassium abietate (produced by dissolving pine resin or colophony in hot dilute caustic potash solution).
  • the resulting coating is brown .and adheres very securely to the metal. In the polished state it possesses a high gloss and can, if required, be coated with a firmly adherent layer of synthetic resin lacquer for the purpose of further increasing the resistance to corrosion.
  • a casting of an alloy containing 4%, of aluminium, 3% of zinc, remainder magnesium, is treated for two hours under normaLpressure at boiling temperature with a 10% aqueous solution of potassium naphthenate (produced by saponifi- 6.
  • a sheet of an alloy containing 6% of aluminium, 1% of zinc, remainder magnesium, is treated under the conditions described in Example 1, with a 6% aqueous solution of the potassium salt of p-oxynaphthoic acid anilide.
  • the resulting layer yellow to green in colour, assumed a bright red colour of great fastness when dipped in a 1% aqueous solution of KB fast red salt.
  • the chemical resistance of the layer can be increased by using only a 5% solution of the potassium salt of p-oxynaphthoic acid anilide, instead of a 6% solution, which also contains 2% of sodium palmitate.
  • a sheet of an alloy containing 6% of aluminium, 1% of zinc, remainder magnesium, is heated in a solution of 40 grams of o-oxyquinoline and 11 grams of caustic soda solution in 1 litre of water, for about 30 minutes at a temperature of 160 C. in an autoclave.
  • a hard, firmly adherent yellow coating, which can be polished and which imparts good protection against corrosion, is produced on the metal, and can, if desired, be subsequently compacted in known manner.
  • a process for theproduction of protective 'coafings upon workpieces .of magnesium and magnesium base alloys which comprises treating the workpiece with an aqueous solution of a salt of an aliphatic carboxylic acid containing at least eight carbon atoms, at temperatures at least so high as to be in the vicinity of the boiling point of said solution.
  • a process for the production of protective coatings upon workpieces of magnesium and magnesium base alloys' which comprises treating the workpiece with an 'aqueous solution of an ammonium salt of an aliphatic carboxylic acid containing at least eight carbon atoms, at temperatures at least so high as to be in the vicinity of the boiling point of said solution.
  • a process for the production of protective coatings upon workpieces of magnesium and magnesium base alloys which comprises treating the workpiece with an aqueous solution of an alkali metal salt of an aromatic carboxylic acid containing at least two carbon rings, at temperatures at least so high as to be in the vicinity of the boiling point of said solution.
  • a process for the production or protective coatings upon workpieces of magnesium and magnesium base alloys which comprises treating the workpiece with an aqueous solution of an ammonium salt of an aromatic carboxylic acid containing at least two carbon rings, at temperatures at least so high as to be in the vicinity of the boiling point of said solution.
  • a process for the production of protective coatings upon workpieces of magnesiumand magnesium base alloys which comprises treating the workpiece with an aqueous solution of an alkali metal salt of an aromatic carboxylic acid containing at least two carbon rings and adapted to act as a dye-stuff component, at temperatures at least so high as to be in the vicinity of the boiling point of said solution, and thereaftertreating the workpiece with a solution of a component adapted to produce a dye-stufi.
  • a process for the production of protective coatings upon workpieces of magnesium and magnesium base alloys which comprises treating the workpiece with an aqueous solution of at least one of those easily water-soluble substances of the group consisting of the salts of aliphatic and aromatic carboxylic acids and of the phenolates which react with magnesium to form substantially water-insoluble compounds, at temperatures at least so high as to be in the vicinity of the boiling point oi. said solution.
  • a process for the production or protective coatings upon workpieces of magnesium and magnesium base alloys which comprises treating the workpiece with an aqueous solution 01. at least.
  • a process for the production of protective coatings upon workpieces of magnesium and magnesium base alloys which comprises treating the workpiece with an aqueous solution of at least one of those easily water-soluble substances of the group consisting of the salts of aliphatic and aromatic carboxylic acids and of the phenolates which react with magnesium to form substantially water-insoluble compounds, at temperatures at least so high as to be in the vicinity of the boiling point of the solution, said solution also containing a water-soluble chromium salt.
  • a process for the production of protective coatings upon workpieces of magnesium and magnesium base alloys which comprises treating the workpiece with an aqueous solution of at least one of those easily water-soluble substances of vicinity of the boiling point of the solution, said the group consisting of the salts of aliphatic solution also containing a water-soluble manand aromatic carboxylic acids and of the ganese salt. phenolates which react with magnesium to form 1 AIQOLF BECK.

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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)

Description

Batented Jan. 21, 1941 eAr-ENT 'l orrlca PROCE S S FOR THE v 12mm MAGNESIUM BASE ALLOYS Adolf Beck, GfistavSiebel, and Eduard Nalitiiiil, Bitter-fold, Germany, assignors, by 'mesne a signments, to Magnesium Development Corporation, a corporation of Delaware No Drawing. motion September 1,1939, Serial No. 223,160. In Germany September 2,
9 Claims. (01. 148-6) This invention relates to a process for the suriacetreatxfient of workpieces of magnesium and magnesium base alloys for thepurpose of forming a protective coating thereon.
Known processes for building up corrosionresisting coatings on magnesium and magnesium base alloys, consist in treating the metal to be protected with solutions of inorganic compounds, particularly chromates, fluorides 'or phosphates. The resulting coatings are generally very. thin and easily damaged; it it be possible at all to produce thicker layers, these are porous and brittle and therefore readily flake off from the metal.
A long time ago it was pointed out that coatings oi. magnesium oleate or resinate produced on magnesium or magnesium base alloys possessed an extremely high resistance tofchemical and mechanical influences, and could 'walsO be coloured and polished. As regards the produc tion of such coatings, however, there was merely an indication that this could be done by heating the parts to be coated for a prolonged period in an oil-water-soap emulsion. 7
According to the present invention corrosion resisting layers are produced on magnesium and magnesium base alloys by treating the metal with aqueous solutions of those salts of carboxylic acid or phenolates which react with magnesium to form substantially insoluble compoundsat temperatures in the vicinity of the boilingpoint of the solutions, but preferably at higher temperatures and in such case, under pressure.
The alkali metal salts, including the ammonium salts, of the saturated and unsaturated fatty; acids (including the iso-fatty acids) and oxy fatty acids. containing eight or more carbon atoms, and also. alkali metal salts, including the ammonium salts, of aromatic carboxylic acids having two or more carbon rings, andthe substitution products thereof, are particularly suitable for use in carrying out the present invention. The use of the free fatty and oxy-fattyiacidsl also of the aromatic carboxylic acids themselves usually fails either because such acids form read: ily soluble magnesium salts or because they are not water-soluble.
The solutions employed in carrying out the invention may, if desired, also contain other suitable solvents, such as ethanol, in addition to water.
It has beenzrimmd-athat the presence in the solutions, of water-soluble sulphates or nitrates accelerates the building up of the protective coatin'gs, while the presence of water-soluble silicates or of water-soluble salts of chromium and manganese, renders the coatings harder and/or more resistant to corrosion. In a similar manner, the nature of the coatings can be graduated by varying the temperature and pressure.
'The coatings produced in accordance with the present invention can be coloured by adding colouring substances to the solution employed for the treatment; the colouring substances may,
however, be produced directly in the coating zfoi'med, by employing for the production of the latter a substance suitable in accordance with the invention, which substance also acts as a dye component and subsequently allowing the solution of a suitable coupling component to act on the coating.
The hereindescribed process may also be applied to articles which have previously been subjected to a surface treatment, for example by a dipping process.
When treating magnesium base alloys the thickness and quality of the coatings depend to a. certain extent, on the proportion of the alloying constituents contained in the magnesium, in the sense that the thickness of .the coating which can be built up varies inversely with the content of alloying constituents However, the quality of the layer is largely independent of the concentration of the solutions employed.
The following examples illustrate the invention:
1; A sheetnof anralloy' containing 2% of manganese-,-remairider magnesium, is heated in an autoclave' ina.3% aqueous solution of potassium Palm-intestin 15 minutes at a temperature of about l'fQf. C. A uniformly yellow coatingabout @102 mm; in thickness and'possessing great resist'an'ce'to abrasion'fis formed on the sheet, and imparts to-tl'ie' latter good resistance to corrosion, including corrosion by sea water.
The addition of 1% of sodium sulphate to the foregoing solution enables the duration of the treatment required to produce a coating oi. the" same thickness to be reduced to 5 minutes.
Similar coatings are obtained in the same manner by using aqueous solutions oi the alkali metal or ammonium salts of stearic acid, oleic acid or linoleic acid.
2. A sheet of an alloy containing 2% of manganese and 0.4% of cerium, remainder'rnagnesium, is treated in an autoclave with an aqueous solution oi! sulphoricinoleate (Turkey-red oil) for at least 20 minutes at a temperature of 180 C. The appearance and properties oi the coating produced are similar to those oi thecoating produced in accordance with Example 1.
3. A sheet of an alloy containing 6% of aluminium, 1% of zinc, remainder magnesium is heated at 180 C. for 15 minutes in an autoclave in a 5% aqueous solution or potassium abietate (produced by dissolving pine resin or colophony in hot dilute caustic potash solution). The resulting coating is brown .and adheres very securely to the metal. In the polished state it possesses a high gloss and can, if required, be coated with a firmly adherent layer of synthetic resin lacquer for the purpose of further increasing the resistance to corrosion.
4. A casting of an alloy containing 4%, of aluminium, 3% of zinc, remainder magnesium, is treated for two hours under normaLpressure at boiling temperature with a 10% aqueous solution of potassium naphthenate (produced by saponifi- 6. A sheet of an alloy containing 6% of aluminium, 1% of zinc, remainder magnesium, is treated under the conditions described in Example 1, with a 6% aqueous solution of the potassium salt of p-oxynaphthoic acid anilide. The resulting layer, yellow to green in colour, assumed a bright red colour of great fastness when dipped in a 1% aqueous solution of KB fast red salt.
The chemical resistance of the layer can be increased by using only a 5% solution of the potassium salt of p-oxynaphthoic acid anilide, instead of a 6% solution, which also contains 2% of sodium palmitate.
7. A sheet of an alloy containing 6% of aluminium, 1% of zinc, remainder magnesium, is heated in a solution of 40 grams of o-oxyquinoline and 11 grams of caustic soda solution in 1 litre of water, for about 30 minutes at a temperature of 160 C. in an autoclave. A hard, firmly adherent yellow coating, which can be polished and which imparts good protection against corrosion, is produced on the metal, and can, if desired, be subsequently compacted in known manner.
What we claim is:
1. A process for theproduction of protective 'coafings upon workpieces .of magnesium and magnesium base alloys, which comprises treating the workpiece with an aqueous solution of a salt of an aliphatic carboxylic acid containing at least eight carbon atoms, at temperatures at least so high as to be in the vicinity of the boiling point of said solution.
2. A process for the production of protective coatings upon workpieces of magnesium and magnesium base alloys',,which comprises treating the workpiece with an 'aqueous solution of an ammonium salt of an aliphatic carboxylic acid containing at least eight carbon atoms, at temperatures at least so high as to be in the vicinity of the boiling point of said solution.
3. A process for the production of protective coatings upon workpieces of magnesium and magnesium base alloys, which comprises treating the workpiece with an aqueous solution of an alkali metal salt of an aromatic carboxylic acid containing at least two carbon rings, at temperatures at least so high as to be in the vicinity of the boiling point of said solution.
4. A process for the production or protective coatings upon workpieces of magnesium and magnesium base alloys, which comprises treating the workpiece with an aqueous solution of an ammonium salt of an aromatic carboxylic acid containing at least two carbon rings, at temperatures at least so high as to be in the vicinity of the boiling point of said solution.
5. A process for the production of protective coatings upon workpieces of magnesiumand magnesium base alloys, which comprises treating the workpiece with an aqueous solution of an alkali metal salt of an aromatic carboxylic acid containing at least two carbon rings and adapted to act as a dye-stuff component, at temperatures at least so high as to be in the vicinity of the boiling point of said solution, and thereaftertreating the workpiece with a solution of a component adapted to produce a dye-stufi.
6. A process for the production of protective coatings upon workpieces of magnesium and magnesium base alloys, which comprises treating the workpiece with an aqueous solution of at least one of those easily water-soluble substances of the group consisting of the salts of aliphatic and aromatic carboxylic acids and of the phenolates which react with magnesium to form substantially water-insoluble compounds, at temperatures at least so high as to be in the vicinity of the boiling point oi. said solution.
' 7. A process for the production or protective coatings upon workpieces of magnesium and magnesium base alloys, which comprises treating the workpiece with an aqueous solution 01. at least.
one of those easily water-soluble substances of the group consisting of the salts of aliphatic and aromatic carboxylic acids andof the phenolates which react with magnesium to form substantially water-insoluble compounds, at temperatures at least so high as to be in the vicinity of the boiling point of the solution, said solution also containing at least one water-soluble salt of the group consisting of sulphates, nitrates, and silicates.
8. A process for the production of protective coatings upon workpieces of magnesium and magnesium base alloys, which comprises treating the workpiece with an aqueous solution of at least one of those easily water-soluble substances of the group consisting of the salts of aliphatic and aromatic carboxylic acids and of the phenolates which react with magnesium to form substantially water-insoluble compounds, at temperatures at least so high as to be in the vicinity of the boiling point of the solution, said solution also containing a water-soluble chromium salt.
9. A process for the production of protective coatings upon workpieces of magnesium and magnesium base alloys, which comprises treating the workpiece with an aqueous solution of at least one of those easily water-soluble substances of vicinity of the boiling point of the solution, said the group consisting of the salts of aliphatic solution also containing a water-soluble manand aromatic carboxylic acids and of the ganese salt. phenolates which react with magnesium to form 1 AIQOLF BECK.
5 substantially Water-insoluble compounds, at GUSTAV SIEBEL. 5
temperatures at least so high as to be in the EDfiARD NACHIIGALL.
US293100A 1938-09-02 1939-09-01 Process for the surface treatment of workpieces of magnesium and magnesium base alloys Expired - Lifetime US2229236A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2419190A (en) * 1942-04-09 1947-04-15 Du Pont Conditioning treatment of magnesium for electroplating
US3183125A (en) * 1961-03-02 1965-05-11 Dow Chemical Co Protective treatment for mg and mg-based alloys
FR2822852A1 (en) * 2001-03-27 2002-10-04 Usinor PROCESS FOR CARBOXYLATION TREATMENT OF METAL SURFACES
US20050067003A1 (en) * 2003-09-26 2005-03-31 Ting-Sheng Tsai Luminous umbrella
JP2016030860A (en) * 2014-07-30 2016-03-07 学校法人 芝浦工業大学 Magnesium-based member having a film excellent in conductivity and corrosion resistance and method for producing the same

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2419190A (en) * 1942-04-09 1947-04-15 Du Pont Conditioning treatment of magnesium for electroplating
US3183125A (en) * 1961-03-02 1965-05-11 Dow Chemical Co Protective treatment for mg and mg-based alloys
FR2822852A1 (en) * 2001-03-27 2002-10-04 Usinor PROCESS FOR CARBOXYLATION TREATMENT OF METAL SURFACES
WO2002077324A3 (en) * 2001-03-27 2003-01-03 Usinor Method for treating metal surfaces by carboxylation
US20050067003A1 (en) * 2003-09-26 2005-03-31 Ting-Sheng Tsai Luminous umbrella
JP2016030860A (en) * 2014-07-30 2016-03-07 学校法人 芝浦工業大学 Magnesium-based member having a film excellent in conductivity and corrosion resistance and method for producing the same

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