US2766199A - Cleaning of magnesium base alloy castings - Google Patents

Cleaning of magnesium base alloy castings Download PDF

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Publication number
US2766199A
US2766199A US428120A US42812054A US2766199A US 2766199 A US2766199 A US 2766199A US 428120 A US428120 A US 428120A US 42812054 A US42812054 A US 42812054A US 2766199 A US2766199 A US 2766199A
Authority
US
United States
Prior art keywords
cleaning
magnesium base
castings
casting
ammonium fluoride
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
US428120A
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English (en)
Inventor
William F Higgins
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.)
Magnesium Elektron Ltd
Original Assignee
Magnesium Elektron Ltd
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 Magnesium Elektron Ltd filed Critical Magnesium Elektron Ltd
Application granted granted Critical
Publication of US2766199A publication Critical patent/US2766199A/en
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
    • C25F1/00—Electrolytic cleaning, degreasing, pickling or descaling

Definitions

  • Castings of such alloys are almost invariably contaminated with the ingredients of the moulding composition particularly .core compositions, which become attached to or embedded in the surface of the casting. This contamination is difficult to remove and consequently it has been common practice to clean the casting by sand blasting or shot blasting.
  • this procedure is effective in cleaning the casting from the moulding composition contaminants, the resultant casting is found to have considerably less resistance to corrosive action than castings which are cleaned by strong chemical agents or by machining, both of which are in many cases undesirable for various reasons.
  • the casting is subjected with its moulding contaminants thereon to anodic treatment whilst immersed in an aqueous solution of ammonium fluoride (NH4F or NH4F.HF) in quantity at least two percent ammonium fluoride by weight of the water, and continuing the treatment until current flow is substantially stopped automatically.
  • aqueous solution of ammonium fluoride NH4F or NH4F.HF
  • the solution may contain ammonium fluoride from 2 percent up to the quantity representing the limit of solubility together with ammonia in quantity corresponding to 5-15 of aqueous ammonia solution of .880 specific gravity.
  • the casting to be treated is made the anode in an electrical circuit supplied with D. C. or A. C. current.
  • the time of treatment depends on various factors such as current density and the degree of contamination of the casting, and may take from half a minute or less for fairly clean castings and up to thirty minutes or more for badly contaminated castings. The time of treatment will however usually be at least fifteen minutes.
  • the electrolyte was prepared by adding to a bath of water 10% by weight of ammonium bi-fluoride and 10% of an aqueous solution of ammonia of .880 specific gravity.
  • the castings were suspended in this electrolyte by means of magnesium clamps which were made the anode in an electrical circuit which included a source of D. C. current supply of volts.
  • the voltage fell to 5 and the current density was about 5 amps. per square foot of casting.
  • the cur-rent density fell to a few microamps and the voltage rose to 80.
  • the current was then switched 01f and the castings removed and rinsed in running water and were found to be completely free from burnt-on and embedded mould and core compositions.
  • a method of cleaning castings of magnesium base alloys having mould contaminants in the surface thereof which comprises removing said mould contaminants thereon by subjecting the said casting to anodic treatment whilst immersed in an aqueous solution consisting of ammonium fluoride, said ammonium fluoride being selected from the group of fluorides consisting of NH4F and NH4F.HF, said aqueous solution containing in quantity at least two percent ammonium fluoride by weight of the water.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
US428120A 1951-07-04 1954-05-06 Cleaning of magnesium base alloy castings Expired - Lifetime US2766199A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB307338X 1951-07-04

Publications (1)

Publication Number Publication Date
US2766199A true US2766199A (en) 1956-10-09

Family

ID=10312293

Family Applications (1)

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US428120A Expired - Lifetime US2766199A (en) 1951-07-04 1954-05-06 Cleaning of magnesium base alloy castings

Country Status (6)

Country Link
US (1) US2766199A (en)van)
BE (1) BE512440A (en)van)
CH (1) CH307338A (en)van)
FR (1) FR1058578A (en)van)
GB (1) GB721445A (en)van)
NL (2) NL94743C (en)van)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2880148A (en) * 1955-11-17 1959-03-31 Harry A Evangelides Method and bath for electrolytically coating magnesium
US3088889A (en) * 1959-06-08 1963-05-07 Gen Motors Corp Electrolytic machining of metal surfaces
US3345276A (en) * 1963-12-23 1967-10-03 Ibm Surface treatment for magnesiumlithium alloys
US3355369A (en) * 1962-12-11 1967-11-28 Agie Ag Ind Elektronik Process using a fluoride electrolyte for the electrolytic and electrochemical working of metals
US5240589A (en) * 1991-02-26 1993-08-31 Technology Applications Group, Inc. Two-step chemical/electrochemical process for coating magnesium alloys
US5470664A (en) * 1991-02-26 1995-11-28 Technology Applications Group Hard anodic coating for magnesium alloys
US20060102484A1 (en) * 2004-11-12 2006-05-18 Woolsey Earl R Anodization process for coating of magnesium surfaces

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1574289A (en) * 1923-01-22 1926-02-23 American Magnesium Corp Protective coating for magnesium
GB294237A (en) * 1927-07-22 1929-09-12 Electrolux Ltd A process for treating aluminium or other light metals
DE660409C (de) * 1937-02-26 1938-05-24 I G Farbenindustrie Akt Ges Verfahren zur Erzeugung von Schutzschichten auf Magnesium und seinen Legierungen
FR840385A (fr) * 1937-12-31 1939-04-25 Procédé de décapage pour le revêtement métallique des métaux
US2468006A (en) * 1948-06-23 1949-04-19 J H Shoemaker Electrolytic cleaning of metal

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1574289A (en) * 1923-01-22 1926-02-23 American Magnesium Corp Protective coating for magnesium
GB294237A (en) * 1927-07-22 1929-09-12 Electrolux Ltd A process for treating aluminium or other light metals
DE660409C (de) * 1937-02-26 1938-05-24 I G Farbenindustrie Akt Ges Verfahren zur Erzeugung von Schutzschichten auf Magnesium und seinen Legierungen
FR840385A (fr) * 1937-12-31 1939-04-25 Procédé de décapage pour le revêtement métallique des métaux
US2468006A (en) * 1948-06-23 1949-04-19 J H Shoemaker Electrolytic cleaning of metal

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2880148A (en) * 1955-11-17 1959-03-31 Harry A Evangelides Method and bath for electrolytically coating magnesium
US3088889A (en) * 1959-06-08 1963-05-07 Gen Motors Corp Electrolytic machining of metal surfaces
US3355369A (en) * 1962-12-11 1967-11-28 Agie Ag Ind Elektronik Process using a fluoride electrolyte for the electrolytic and electrochemical working of metals
US3345276A (en) * 1963-12-23 1967-10-03 Ibm Surface treatment for magnesiumlithium alloys
US5240589A (en) * 1991-02-26 1993-08-31 Technology Applications Group, Inc. Two-step chemical/electrochemical process for coating magnesium alloys
US5470664A (en) * 1991-02-26 1995-11-28 Technology Applications Group Hard anodic coating for magnesium alloys
US20060102484A1 (en) * 2004-11-12 2006-05-18 Woolsey Earl R Anodization process for coating of magnesium surfaces

Also Published As

Publication number Publication date
NL94743C (en)van)
NL170633B (nl)
GB721445A (en) 1955-01-05
CH307338A (fr) 1955-05-31
BE512440A (en)van)
FR1058578A (fr) 1954-03-17

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