US3510365A - Process of pretreating ferrous metal surfaces before phosphatizing - Google Patents
Process of pretreating ferrous metal surfaces before phosphatizing Download PDFInfo
- Publication number
- US3510365A US3510365A US681022A US3510365DA US3510365A US 3510365 A US3510365 A US 3510365A US 681022 A US681022 A US 681022A US 3510365D A US3510365D A US 3510365DA US 3510365 A US3510365 A US 3510365A
- Authority
- US
- United States
- Prior art keywords
- manganese
- pretreating
- bath
- orthophosphate
- phosphate
- 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
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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
- C23C22/78—Pretreatment of the material to be coated
Definitions
- the present invention relates to a process for treating metal surfaces and more particularly, it relates to a process for forming improved, finely crystalline, adherent manganese phosphate coatings on ferrous metal surfaces.
- the type of manganese phosphate coating layer formed on the surface depends to a great extent upon the type of pretreatment used prior to the application of the coating solution.
- the ferrous metal surfaces have been pretreated with a strongly alkaline aqueous cleaning solution, very coarse, crystalline layers are produced. .Even after long periods of phosphatizing, the coatings produced frequently exhibit large areas in which there are no connecting crystalline layers.
- acid solutions such as aqueous solutions of hydrochloric or sulfuric acids, very coarse, crystalline manganese phosphate layers are also produced.
- the metal surface is degreased with an organic solvent, such as petroleum solvent, rather than being pretreated with an alkaline cleaner or acid pickling solution, the resulting coating layers have a fine, even, crystalline structure.
- an organic solvent such as petroleum solvent
- an object of the present invention to provide an improved process for forming a dense, finely crystalline manganese phosphate coating on ferrous surfaces.
- a further object of the present invention is to provide an improved pretreatment for ferrous surfaces, prior to the application of a manganese phosphate coating solution, which pretreatment promotes the formation of a dense, finely crystalline manganese phosphate coating on the ferrous surface.
- Another object of the present invention is to provide an improved method for treating ferrous metal surfaces whereby a dense, finely crystalline manganese phosphate coating is produced on the surface even after cleaning or pickling of the surface with a strong alkaline or acidic solution.
- the present invention includes a metal treating process wherein a ferrous metal surface is contacted with an aqueous pretreating composition which comprises an admixture of water and manganese-II-orthophosphate, the contact with the pretreating solution being sufficient to effect a conditioning of the ferrous metal surface such that the subsequent application of a manganese phosphatizing solution produces a finely crystalline manganese phosphate coating.
- the treated surface is then phosphatized with a conventional manganese phosphatizing solution. This process results in the formation of a finely crystalline manganese phosphate coating on the treated metal surfaces, even where the treatment with the aqueous manganese-II-phosphate composition is preceded by an acid or alkaline treatment.
- the ferrous metal surfaces to be coated are contacted with an aqueous pretreating composition containing a manganese-II-phosphate.
- This pretreating composition is an aqueous mixture in which the diflicultly soluble manganese-II-orthophosphate is finely dispersed.
- the manganese-II-orthophosphates which are used may be prepared in various suitable ways, such as by the alkaline neutralization of phosphoric acid solutions of manganese phosphate, the neutralization being carried out by either the addition of the acid to the base or vice versa, to a pH 3 of about 7.5.
- manganese- II-orthophosphate examples include the precipitation of this material by the addition of dior tri-sodium phosphate to a phosphate free solution of a manganese salt, such as manganese chloride, manganese carbonate or the like.
- a manganese salt such as manganese chloride, manganese carbonate or the like.
- the mol ratio of the manganese to P is within the range of about 120.8 to 0.33, although mol ratios of P 0 which are outside of this range may also be used in many instances. In many instances, it has been found that particularly advantageous results are obtained where at least part of the manganese-II-orthophosphate in the prerinse composition is present as hureaulite.
- Hurealulite is a manganous phosphate mineral having the general formula H Mn (PO .4H O.
- Aqueous prerinse mixtures containing hureaulite are found to produce extremely fine crystalline manganese phosphate layers on the subsequent application of the manganese phosphate phosphatizing solution, the crystals of which are generally being sufiiciently fine that they cannot be observed by the naked eye.
- the particle size of the manganese-II-orthophosphate in the pretreating solution has an effect on the activation or crystal refining effectiveness which is obtained.
- the activating or crystal refining effect of the pretreatment is increased.
- the manganese-II-orthophosphate used desirably contains about 50% of material having a particle size below about 3.5 microns and about 90% of a particle size which is less than about 30 microns.
- the manganese-II-orthophosphate should be as highly dispersed as possible in the prerinse bath.
- the amount of the manganese-II-orthophosphate in the pretreating bath will vary, depending upon the degree of activation or crystal refinement which is desired, greater crystal refinement being obtained as the amount of the manganese-II-orthophosphate in the bath is increased.
- amounts of manganese-II-orthophosphate in the bath within the range of about 0.002 to about 5 grams per liter have been found to be preferred.
- amounts of the manganous phosphate in excess of about 5 grams per liter may be used, such larger amounts have not generally been found to result in further improvement of the crystal refinement and, in some instances, may produce sludge deposits upon the metal surfaces treated. Accordingly, it is generally preferred that the pretreating bath contain the manganese-II-orthophosphate in an amount within the range which has been specified.
- the pretreating bath desirably may also contain an alkali metal condensed phosphate.
- alkali metal condensed phosphate it is intended to include the condensed phosphates of sodium, potassium, lithium, cesium, and rubidium.
- the addition of such condensed phosphate to the pretreating bath are found to aid in obtaining a high degree of dispersion of the manganous phosphate and also to help in preventing settling of the manganous phosphate in the pretreating bath.
- the tetraalkali metal pyrophosphates are preferred, such as tetrasodium pyrophosphate.
- the tetrasodium pyrophosphate may also be mixed with dialkali metal pyrophosphates, such as disodium pyrophosphate.
- dialkali metal pyrophosphates are not used alone as it can cause phosphate layer formation in the prerinse bath, because of its low pH value. The formation of such a phosphate layer in the prerinse bath may then interfere with the formation of the desired protective manganese phosphate coating in the subsequently applied manganese phosphate coating bath.
- Higher condensed phosphates such as the alkali metal tripolyphosphates may also be used in the pretreating bath although such higher phosphates have, generally, been found to be less effective than the pyrophosphates.
- these condensed phosphates are, included in the prerinse bath, they are desirably present in amounts within the range of about 0.5 to 5 grams perliter of the pretreating bath.
- the stability of the pretreating bath may be further enhanced by including therein a surface active agent, particularly a non-ionic surface active agent.
- the crystal refining effectiveness of the pretreating baths of the present invention may be further improved by also incorporating in the bath a finely distributed, difficultly insoluble iron orthophosphate and/or calcium pyrophosphate.
- a finely distributed, difficultly insoluble iron orthophosphate and/or calcium pyrophosphate are included in the pretreating bath, they are desirably present in amounts comparable to the amounts of the manganese-II-orthophosphates, i.e., amounts within the range of about 0.002 to 5.0 grams per liter.
- the crystal refining effectiveness of these additives is increased as their particle size is decreased.
- the iron orthophosphate or calcium pyrophosphate preferably has a particle size which is similar to that of the manganese-II-orthophosphate, i.e., 50% of the material has a particle size less than about 3.5 microns and about of the material has a particle size below about 30 microns.
- the manganese-II-orthophosphate i.e. 50% of the material has a particle size less than about 3.5 microns and about of the material has a particle size below about 30 microns.
- satisfactory crystal refining or surface activation may also be obtained in many instances using materials which have a larger particle size than this preferred range.
- the prerinse bath of the present invention may be applied to the metal surface in any convenient manner.
- the ferrous metal surface may be immersed in the pretreating bath or the bath may be flooded or sprayed onto the metal surface.
- the pretreating bath when applied to the metal surface, may be at any suitable temperature, although temperatures between about room temperature (20 C.) and C. are preferred.
- rinsing of the metal surface after the application of the pretreating bath is not necessary, although the use of such a rinse has not been found to have any appreciable adverse affect on the activation or crystal refining efiiciency of the pretreatment bath.
- manganese phosphate phosphatizing solutions as are known to those in the art, may be utilized and will produce the desired fine crystalline manganese phosphate coating on the metal surface.
- these phosphatizing baths are aqueous acidic solutions of manganese phosphate which may contain one or more additives, including oxidizing agents, such as nitrates, nitrites, chlorates, bromates, sulfites, perchlorates, peroxides, permanganates, organic nitro compounds, and the like.
- metal ions such as nickel, copper, and the like may also be included in the phosphatizing composition.
- the manganese phosphate coating composition may be applied in any suitable manner, such as by immersion of the metal surface in the phosphatizing solution. Excellent coatings are also produced, however, by flooding or spraying the phosphatizing solution onto the metal surface.
- the ferrous metal surfaces to be treated are first subjected to a suitable cleaning operation.
- this cleaning treatment may be of the organic solvent type, the improvement obtained in producing a finely crystalline manganese phosphate coating on the metal surface is most pronounced when the cleaning step includes the use of a strong alkaline cleaner and/or an acid pickel.
- the ferrous metal surface is first subjected to the action of an alkaline cleaning solution and/or an acid pickling solution, suitable solutions of these types being known to those in the art. Thereafter, the cleaned metal surface is subjected to the action of the pretreating bath of the present invention, for a period sufficient to produce the desired activation of the metal surface.
- treating times will range from a few seconds, e. g., seconds, up to several minutes, e.g. 10 minutes.
- Other treating times which will produce the desired activation of the metal surface may, of course, also be used.
- the aqueous dispersion being at a temperature of 90 centigrade and being stirred.
- steel panels and tempered steel cog wheels were subjected to one or more various pretreating steps and were then phosphatized in an aqueous manganese phosphate coating solution.
- the treating steps used were as follows:
- -A method for the treatment of ferrous metal surfaces before phosphatizing with a manganese phosphate coating solution which comprises contacting the ferrous metal surfaces prior to the application of the manganese phosphate coating solution, with an aqueous pretreating mixture, which mixture contains manganese-II-orthophosphate, and maintaining the aqueous pretreating mixture in contact with the surface for a period sufiicient to elfect activation thereof.
- pretreating mixture also contains an alkali metal condensed phosphate.
- alkali metal condensed phosphate is an alkali metal tetrapyrophosphate.
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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
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19661521889 DE1521889B1 (en) | 1966-11-30 | 1966-11-30 | METHOD OF PHOSPHATING IRON AND STEEL |
Publications (1)
Publication Number | Publication Date |
---|---|
US3510365A true US3510365A (en) | 1970-05-05 |
Family
ID=5674916
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US681022A Expired - Lifetime US3510365A (en) | 1966-11-30 | 1967-11-06 | Process of pretreating ferrous metal surfaces before phosphatizing |
Country Status (1)
Country | Link |
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US (1) | US3510365A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3819422A (en) * | 1971-12-28 | 1974-06-25 | Amchem Prod | Method for applying zinc phosphate coatings to metal surfaces |
JPS5613484A (en) * | 1979-07-06 | 1981-02-09 | Fr Dou Purodeyuitsu Andeyusuto | Phosphate treating method of surface of iron and steel by using manganese |
US4957568A (en) * | 1988-04-28 | 1990-09-18 | Henkel Kommanditgesellschaft Auf Aktien | Composition and process for activating metal surfaces prior to zinc phosphating and process for making said composition |
WO1995008007A1 (en) * | 1993-09-17 | 1995-03-23 | Brent International Plc | Pre-rinse for phosphating metal surfaces |
EP1705265A1 (en) * | 2003-12-04 | 2006-09-27 | Sumitomo Metal Industries, Ltd. | Surface adjustment treatment prior to chemical treatment of steel product |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2874081A (en) * | 1956-08-02 | 1959-02-17 | Parker Rust Proof Co | Pretreatment solution for phosphate coating, method of preparing the same and process of treating metal surfaces |
-
1967
- 1967-11-06 US US681022A patent/US3510365A/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2874081A (en) * | 1956-08-02 | 1959-02-17 | Parker Rust Proof Co | Pretreatment solution for phosphate coating, method of preparing the same and process of treating metal surfaces |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3819422A (en) * | 1971-12-28 | 1974-06-25 | Amchem Prod | Method for applying zinc phosphate coatings to metal surfaces |
JPS5613484A (en) * | 1979-07-06 | 1981-02-09 | Fr Dou Purodeyuitsu Andeyusuto | Phosphate treating method of surface of iron and steel by using manganese |
US4311536A (en) * | 1979-07-06 | 1982-01-19 | Compagnie Francaise De Produits Industriels | Processes of phosphating surfaces of iron and of steel with manganese |
JPS6033191B2 (en) * | 1979-07-06 | 1985-08-01 | コムパニ フランセ−ズ ド プロデユイ アンデユストリエル エス.ア−. | Method for forming manganese phosphate film on metal surface of iron or steel |
US4957568A (en) * | 1988-04-28 | 1990-09-18 | Henkel Kommanditgesellschaft Auf Aktien | Composition and process for activating metal surfaces prior to zinc phosphating and process for making said composition |
WO1995008007A1 (en) * | 1993-09-17 | 1995-03-23 | Brent International Plc | Pre-rinse for phosphating metal surfaces |
US5868873A (en) * | 1993-09-17 | 1999-02-09 | Brent International Plc | Pre-rinse for phosphating metal surfaces |
EP1705265A1 (en) * | 2003-12-04 | 2006-09-27 | Sumitomo Metal Industries, Ltd. | Surface adjustment treatment prior to chemical treatment of steel product |
EP1705265A4 (en) * | 2003-12-04 | 2009-05-13 | Sumitomo Metal Ind | Surface adjustment treatment prior to chemical treatment of steel product |
US7666266B2 (en) | 2003-12-04 | 2010-02-23 | Sumitomo Metal Industries, Ltd. | Surface conditioning prior to chemical conversion treatment of a steel member |
NO341188B1 (en) * | 2003-12-04 | 2017-09-04 | Sumitomo Metal Ind | Surface conditioning prior to chemical treatment of steel product |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: HOOKER CHEMICALS & PLASTICS CORP 32100 STEPHENSON Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:OXY METAL INDUSTRIES CORPORATION;REEL/FRAME:003942/0016 Effective date: 19810317 |
|
AS | Assignment |
Owner name: OXY METAL INDUSTRIES CORPORATION Free format text: CHANGE OF NAME;ASSIGNOR:OXY METAL FINISHING CORPORATION;REEL/FRAME:003967/0084 Effective date: 19741220 |
|
AS | Assignment |
Owner name: OCCIDENTAL CHEMICAL CORPORATION Free format text: CHANGE OF NAME;ASSIGNOR:HOOKER CHEMICAS & PLASTICS CORP.;REEL/FRAME:004126/0054 Effective date: 19820330 |
|
AS | Assignment |
Owner name: PARKER CHEMICAL COMPANY, 32100 STEPHENSON HWY., MA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:OCCIDENTAL CHEMICAL CORPORATION;REEL/FRAME:004194/0047 Effective date: 19830928 |