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
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
  • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
  • C23G1/10—Other heavy metals
• • 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
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
  • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
  • C23G1/08—Iron or steel
  • C23G1/086—Iron or steel solutions containing HF
• • 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
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
  • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
  • C23G1/10—Other heavy metals
  • C23G1/106—Other heavy metals refractory metals
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/34—Pretreatment of metallic surfaces to be electroplated
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/34—Pretreatment of metallic surfaces to be electroplated
  • C25D5/38—Pretreatment of metallic surfaces to be electroplated of refractory metals or nickel
• • 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
  • C25F1/02—Pickling; Descaling
  • C25F1/04—Pickling; Descaling in solution
• • 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
  • C25F1/02—Pickling; Descaling
  • C25F1/04—Pickling; Descaling in solution
  • C25F1/08—Refractory metals

Definitions

• the invention relates to a method for the chemical removal of oxide layers from objects made of metals, in particular titanium, titanium alloys, nickel, nickel alloys and chromium-nickel steels, for subsequent coating with metals, in particular in an organic electrolyte.
• workpieces made of titanium, titanium alloys, nickel, nickel alloys and chrome-nickel steels always have an oxide layer on their surface, which spontaneously forms again after removal by chemical or mechanical means in air or in aqueous media.
• the object of the invention is therefore to create a method by means of which it is possible to effectively remove the oxide films of workpieces made of metals, in particular the aforementioned metals or alloys, without impairing the dimensional accuracy of the workpieces and the material properties, remove screws, for example.
• the organic media used are those in which both the hydrogen fluoride and alkali metal fluoride or ammonium fluoride can be dissolved.
• the media preferably consist of alcohols, in particular methanol.
• the treatment is preferably carried out with a medium containing 3 to 8% by weight of hydrogen fluoride, 5 to 8% by weight of ammonium fluoride and 5 to 10% by weight of an alkali fluoride, in particular sodium fluoride.
• the treatment temperature is preferably between 10 ° C and 50 ° C.
• the removal of the oxide layer can preferably be supported electrochemically by the process according to the invention, the procedure being in particular such that adding a conductive salt, e.g. Sodium sulfate, and using counter electrodes e.g. can consist of titanium or platinum, alternately switching the workpieces anodically and cathodically.
• a conductive salt e.g. Sodium sulfate
• counter electrodes e.g. can consist of titanium or platinum
• the workpieces are preferably rinsed with an inert solvent under a water-vapor and oxygen-free atmosphere, in particular in an inert gas atmosphere, and they are fed to the device in which the metal coating, preferably by electrolytic means, is also carried out under oxygen-free and water-vapor-free conditions , takes place, in particular aluminum, copper, nickel and silver, but also germanium, beryllium, molybdenum, tungsten and zirconium.
• electrolytic deposition known electrolyte systems can be used (US Pat. No. 2,763,605; Hurley FH, Wier TP "Electrodeposition of Al from nonaquous solutions", J. Elektrochem. Soc.
• the workpiece Under inert gas, the workpiece is placed in a pickling solution consisting of a methanolic solution of 8% hydrogen fluoride, 5% ammonium fluoride and 10% sodium fluoride brings.
• This solution contains platinum electrodes which, like the workpiece, are connected to a voltage source. These make it possible to change the potential from + 10 V to - 10 V within one second.
• the electrolyte consists of an ethereal solution of 3 moles of aluminum chloride and about 1 mole of LiH or LiAlH and allows it to be reversed direct current at a current density of about 3 A. / Dm 2 smooth, dense aluminum layers of approx. 0.08 cm, whereby excellent adhesion to the base material is achieved.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
• ing And Chemical Polishing (AREA)
• Physical Vapour Deposition (AREA)

Applications Claiming Priority (2)

Publications (2)

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Cited By (3)

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Citations (3)

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• 1980
  • 1980-12-19 DE DE3048083A patent/DE3048083C2/de not_active Expired
• 1981
  • 1981-11-05 EP EP81109537A patent/EP0054743B1/fr not_active Expired
  • 1981-12-09 US US06/329,115 patent/US4525250A/en not_active Expired - Fee Related

Patent Citations (3)

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