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
  • 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
  • C23C22/73—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 characterised by the process
• • 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
  • C23C22/07—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 containing phosphates
  • C23C22/08—Orthophosphates
  • C23C22/18—Orthophosphates containing manganese cations
  • C23C22/182—Orthophosphates containing manganese cations containing also zinc cations
• • 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
  • C23C22/07—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 containing phosphates
  • C23C22/08—Orthophosphates
  • C23C22/18—Orthophosphates containing manganese cations
  • C23C22/182—Orthophosphates containing manganese cations containing also zinc cations
  • C23C22/184—Orthophosphates containing manganese cations containing also zinc cations containing also nickel cations

Definitions

• This invention relates to a process for phosphating metal surfaces, and to a composition suitable for use in that process.
• Japanese Patent Publication (unexamined) No.107784/ 1980 (Nippon Paint Co.Ltd.) concerns a method of phosphating iron-based metal surfaces which is particularly suitable for treating manufactured products having complicated-surfaces, such as -automobile bodies.
• the method is. in use commercially in the automotive-industry for pretreating automobile bodies prior to cationic electrocoating, which is a, coating process now used extensively in this industry.
• the phosphating method is carried-out by first subjecting the metal surface to a dipping treatment with an acidic aqueous solution containing 0.5 to 1.5 g/l of zinc ion, 5 to 30 g/l of phosphate-ion, and 0.01 to 0.2 g/1 of nitrite ion and/or 0.05 to 2 g/1 of m-nitrobenzenesulfonate ion at a bath temperature of 40 to 70°C for 15 seconds or more, followed by spraying with the above solution for 2 seconds or more.
• the present invention provides an improved phosphating method for metal surfaces, which is particularly suitable for treating metal surfaces, such as-those of car bodies, which have both iron-based surfaces and zinc-based surfaces.
• the method is especially advantageous for forming phosphate coating films suitable for electrocoating particularly cationic electrocoating.
• the invention provides a process for phosphating an iron- or zinc-based metal surface comprising subjecting the metal surface to a dipping treatment in an acidic aqueous solution characterised in that the solution contains:
• the invention also provides an acidic aqueous composition for phosphating an iron- or zinc-based metal surface characterised in that the composition is this solution.
• the conversion coating accelerator is preferably at least one of the following:
• the acidic aqueous solution may also contain one or more of the following:
• the metal surface can then be coated with a siccative coating, for example by a known electrocoating process, preferably by the cationic electrocoating process.
• iron- or zinc-based metal surface means iron-based surfaces, iron alloy-based surfaces, zinc-based surfaces, and zinc alloy-based surfaces.
• Zinc- and zinc alloy-based surfaces include, for example, zinc plated steel plate formed by hot dipping, alloyed zinc plated steel plate formed by hot dipping, zinc plated steel plate formed by electroplating and alloyed zinc plated steel plate formed by electroplating.
• An important advantage of the present invention is that surfaces of metal components, such as car bodies, that contain both iron-based surfaces and zinc-based surfaces can be treated by the process of the invention with excellent results.
• the process of the invention produces better conversion coatings than are obtainable with conventional dip treating processes, and the amount of etching of the metal surfaces during the present process is only 2/3 to 4/5 that of conventional processes, so that both the quantity of chemicals used in the process as well as sludget formation is only from 2/3 to 4/5 that of conventional processes.
• the present process is equally applicable to the treatment of a single-metal surface of a type described above.
• a particularly useful method of carrying out the present process is first to degrease the metal surface to be phosphated for example by spraying and/or dipping the metal-surface in a known alkaline-degreasing agent at 50°-60°C for two minutes; washing the metal surface with tap water; spraying and/or dip treating the metal surface with a known surface conditioner at room temperature for 10-30 seconds; dipping the surface into the present acidic aqueous solution at 40°-70°C for at least 15 seconds; and washing the metal surface with tap water followed by deionized water.
• the present acidic aqueous solution has a zinc ion concentration within the range of 0.5 to 1.5 g/1.
• the amount of zinc ion is less than about 0.5 g/l, an even phosphate film is not formed on an iron-based surface, and a partially blue-coloured film is formed.
• the amount of zinc ion exceeds about 1.5 g/1, then though an even phosphate film is formed, the film that forms on an iron-based surface tends to be in the-form of leaf-like crystals, such as those formed in the spray process, which are unsuitable as a substrate for cationic electrocoating.
• the amount of manganese-ion is less than about 0.6 g/l, the manganese content in the film formed on the zinc-based surface is insufficient, resulting in inadequate adhesivity of the coating film to the phosphate substrate after cationic electrocoating.
• the amount of manganese ion exceeds about 3 g/l, no further improvement in the phosphate coating is realized, and hence it is uneconomical to use amounts in excess of about 3 g/l.
• the conversion coating on iron-based surfaces is inadequate, forming yellow rust, etc.
• the amount of the accelerator exceeds the designated higher amount, a blue-coloured uneven film is formed on the iron-based surface.
• a source of zinc ions for use in the practice of the invention, one or more of the following can be employed: zinc oxide, zinc carbonate, and zinc nitrate.
• a source of phosphate ions one or more of the following can be used: sodium phosphate, zinc phosphate, and manganese ⁇ phosphate.
• manganese carbonate manganese nitrate
• manganese chloride manganese phosphate
• a source of conversion coating accelerators one or more of the following can be employed: sodium nitrite, ammonium nitrite, sodium m-nitrobenzenesulfonate, and hydrogen peroxide.
• the addition of the nickel ion results in further improvement in the performance of the phosphate conversion coating, so that the adhesion and the corrosion-resistance of the film produced by cationic electrocoating are also further improved.
• nickel carbonate, nickel nitrate, nickel chloride or nickel phosphate can be used for nickel ions; sodium nitrate, ammonium-nitrate, zinc nitrate, manganese nitrate or nickel nitrate for nitrate ions; and chloric acid, sodium chlorate or ammonium chlorate for chlorate ions.
• the present process is usually carried out at a temperature-in the range of 40° to 70°C, preferably 45° to 60°C.
• a temperature-in the range of 40° to 70°C preferably 45° to 60°C.
• the conversion coating deteriorates, and long periods of treatment time are required to obtain a satisfactory coating.
• the temperature is higher than about 70°C, the conversion coating accelerators begin to decompose at an unacceptable rate, changing the composition of the bath and resulting in an unacceptable conversion coating. Also, precipitates begin to form in the bath.
• the duration that the metal surface contacts the solution in the dip treatment is usually at least 15 seconds, and preferably is from 30 to 120 seconds. When treatment times shorter than about 15 seconds are employed, an adequate phosphate film is not formed.
• the components can advantageously be subjected first to dipping treatments for 15 seconds or more, preferably 30 to 90 seconds, and then to spray treatment with the solution for 2 seconds or more, preferably for 5 to 45 seconds.
• the spray treatment is preferably carried out for as long a period within the above range as the speed of the production line will permit.
• the dipping treatment according to the present invention includes the combination of dipping followed by spraying.
• EXAMPLES I to VIII are Examples of the process and compositions of the invention.
• EXAMPLESIX toXIV are Examples using known compositions, given for comparison purposes.

Landscapes

• Chemical & Material Sciences (AREA)
• Metallurgy (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Chemical Treatment Of Metals (AREA)
• Laminated Bodies (AREA)
• Chemically Coating (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)
• Glass Compositions (AREA)
• Secondary Cells (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=12524551

Family Applications (1)

Country Status (10)

Cited By (6)

Families Citing this family (24)

Citations (3)

Family Cites Families (1)

• 1981
  • 1981-03-16 JP JP56038411A patent/JPS57152472A/ja active Granted
• 1982
  • 1982-03-15 MX MX191815A patent/MX156539A/es unknown
  • 1982-03-15 AU AU81507/82A patent/AU554406B2/en not_active Expired
  • 1982-03-15 CA CA000398352A patent/CA1200739A/fr not_active Expired
  • 1982-03-15 MX MX011955A patent/MX172180B/es unknown
  • 1982-03-15 BR BR8201400A patent/BR8201400A/pt not_active IP Right Cessation
  • 1982-03-16 AT AT82301330T patent/ATE33684T1/de not_active IP Right Cessation
  • 1982-03-16 DE DE8282301330T patent/DE3278367D1/de not_active Expired
  • 1982-03-16 ES ES510472A patent/ES8302127A1/es not_active Expired
  • 1982-03-16 CS CS821795A patent/CS179582A2/cs unknown
  • 1982-03-16 EP EP82301330A patent/EP0060716B1/fr not_active Expired

Patent Citations (3)

Non-Patent Citations (1)

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