DE1165378B - Bath for the production of non-metallic coatings on metallic objects - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: C23f

German class: 48 dl-7/00

Number: 1165 378

File number: J 14346 VI b / 48 dl

Filing date: January 30, 1958

Opening day: March 12, 1964

The invention relates to improved acidic, aqueous baths for coating metals with a solid adherent protective layer of a salt, such as. B. a phosphate, chromate or oxalate or a Oxide.

Salt or oxide coatings are applied to metal, e.g. B. the corrosion resistance and the To improve the adhesion of paints and to create lubricants or layers containing lubricants to be applied in metal drawing processes, and it is known that these coatings can be produced by treating the metal surface with acidic solutions, e.g. B. can be metals with firmly adhering Provide phosphate coatings by treating them with acidic solutions, which in general Contain iron, manganese, zinc, sodium, potassium, ammonium and magnesium phosphates.

It is also known that phosphate coatings can be produced with the aid of solutions, the metal phosphates of which the metal itself does not get into the coating. Examples are solutions, which are based on sodium, potassium, ammonium and magnesium phosphates with which Coatings are formed which predominantly consist of phosphates of the treated metal, e.g. B. iron phosphates consist of ferrous objects.

These solutions can also contain oxidizing agents such as nitrates, nitrites and chlorates.

In a similar way one can produce oxalate coating, by treating the metal with acidic oxalate solutions, and furthermore one can through Treatment with acidic, oxidizing solutions produces oxide coatings.

From the German patent specification 825 478 it is known a bath of an organic cleaning agent cover with a layer of water for metals consisting of chlorinated naphthalenes, for example, in order to avoid evaporation losses of the organic cleaning agent. Of the Wetting agents or emulsifiers can be added to the aqueous top layer and dissolved in it. Such baths should be used to clean metallic surfaces from lubricating oils, greases and the like.

To metallic surfaces with a phosphate coating or similar on the surfaces To provide adhering inorganic coating, it is known to degrease the surfaces beforehand and the To keep the surface of the treatment bath in question free of oil and grease. Although the above mentioned Cleaning baths can be used to clean metal surfaces before phosphating, it cannot be concluded from this that in the case of a bath for the production of non-metallic coatings on metallic objects

Applicant:

Imperial Chemical Industries Limited, London

Representative:

Dr.-Ing. H. Fincke and Dipl.-Ing. H. Bohr,

Patent Attorneys, Munich 5, Müllerstr. 31

Named as inventor:

Richard Elliott Shaw, Windsor, Berkshire

(Great Britain)

Claimed priority:

Great Britain January 30, 1957 (No. 3252)

Phosphating bath an oily surface layer can be used because the use of a such a layer is in contrast to the findings described.

From the German patent specification 823 677 it is known, the surface of an aqueous chrome bath, that is used to treat metals, to cover with a layer of hydrocarbons, however, it is stated there that this is disadvantageous in that resinous oxidation products are formed.

From the French patent specification 856 526 it is known, the surface of aqueous chemical Covering baths including phosphate baths with a layer of an oily material. It was now found that this oily material should be a liquid aliphatic hydrocarbon and that In addition, both the aqueous and the oily layer of the bath have a soluble surface-active agent Agent should be contained in an amount insufficient to provide one in these two layers To form emulsion. When using such a bath, the surface becomes through the upper layer of oil the underlying aqueous layer covered, the oil taking the action of the aqueous layer does not adversely affect the metal surfaces. It has been found that improved inert

liquid cover layers are obtained if they consist of an aliphatic hydrocarbon, which has a viscosity of less than 100 cP at the working temperature of the bath, and if a

409 538/496

at the working temperature in the treatment solution The amount of surfactant in the and surface bath soluble in the cover layer relative to that in the layer is thus active agent is present in such an amount that depending on the prevailing temperature, and in emulsification between cover layer and concern for best results is a balance action solution is excluded. 5 to achieve. Attempts have been made at The material of the cover layer must be inert to the bath, however, a surfactant d. H. against reduction or attack that was not added to the covering material, and at acid bath or atmospheric these experiments were difficult for the plates Oxygen can be flushed free from the cover layer at the working temperature of the bath. Plates, be constant. On baths that have been treated 10 or 15 minutes later for the formation of oxide, layers are applied, no oxidizing could be rinsed much easier because in the materials that can be used. Furthermore, masking material must penetrate surfactant the material was of a lower density than the solution. Within about 30 minutes a own. The layer itself is preferably under-equilibrium, and then occurred when rinsing at least 10 mm thick, so that the development of acid 15 no longer poses any difficulties. In a similar way Attempts have been carried out to prevent vapors and splashes from being extremely effective. It preferably contains only a few or surface-active agents in the cover material, but not No material at all that was added to the bath at working temperatures, and here too it could temperature of the bath is volatile, and also has the material of the cover layer, which on the plate after applied material adhered at the working temperature of the immersion, only incompletely removed Bath has such a viscosity that the covering will be. For panels that were treated later, layer, if you z. B. when introducing or when all cover material could be removed and without Removal of objects or in the event of difficulties being rinsed off, since the upper gas or vapor bubbles have been ruptured, both surfactants at this point in time can regress again. 25 bath as well as in the cover layer.

The material of the cover layer should be preferred. The extent to which the surfactant is used

wise have the lowest possible viscosity at working temperature in the bath or in the cover

with the requirement to make material soluble is of some importance. Alkyl

is that the material at the working temperature trimethylammonium salts are up to 100 ° C

is almost non-volatile. Though working viscosity, measure water-soluble to prevent the bath

activities of less than 100 cP can be used by introducing the salts into the cover layer.

You must of course be careful to kick. Some agents can be insufficiently water-

that the flash point of the cover layer form- be soluble and are preferably of the ab-

the material is above the working temperature. top layer dissolved, which is then attached to the treated

For this reason, a viscosity between 2 35 will adhere to the object and emulsify in the treatment bath.

and 10 cP at working temperature preferred. can be yawed.

The covering agents are at the working temperature. It is advisable to use a dye of the covering

of the bath liquid aliphatic hydrocarbons, layer incorporated, so that the layer thickness

like liquid paraffin and various types of oil. can easily observe. The colored layer can

In a bath that is used to coat metal 40, it is also used to warn workers that the surfaces is applied, preferably an underlying bath is very hot, though nonionic surfactant applied. No steam or smoke development occurs. The required amount of surfactant. A suitable red dye must be heat stable. Means depends on the working temperature, the handling The invention is based on the following treatment time and the amount of gas, which is explained further during the 45 games. Coating is developed. As already mentioned,

the cover layer must consist of an inert liquid Example 1. The amount of surface-active agent added must emulsify the covering. A phosphate coating solution of the foil layer in the treatment liquid was prepared in such an amount that the upper weight percent next tension of the bath was less than 40 dynes / cm . “ _{No is} reduced. . * ■ ' '

There are also cationic surfactants pt ^ Tt So Ϊ ? 'i 5

and especially quaternary ammonium compounds 55 μ>? CNO ϊ 1 'fi

genes are suitable, but generally non-iono _XT ! ¹ ^. .v ■ ■ · ■ · ■ · .; · ■ ■ ■ · · ·. '

Those surfactants are more suitable. Also an- Nichüonogenes surface-active

ionic surface active agents can be used w τι t

but then the amount of Kest

Accelerating agent applied to drawing method 60 The nonionic surface active agent was

increase. an anhydrous condensation product of a long-

Another advantage of using a top-chain fatty alcohol with ethylene oxide,

surfactant, which is in both the hand- The above solution was made with a 12 mm

bath as well as in the cover layer is soluble, thick layer of a saturated hydrocarbon

consists in the fact that the cover layer is then 65 fabric material with a flash point of 155 ° C and

Storage is used to store excess surfactants with a viscosity of 3.5 cP at working temperature,

To take up means from the treatment liquid which contained a heat-stable red dye,

can escape at elevated temperatures. covers. The solution and the cover layer were

then heated to 90 ° C. and held at this temperature for 10 minutes so that a certain part of the surfactant could penetrate into the cover layer. Cold-rolled steel plates were degreased by treatment in a conventional degreasing system working with trichlorethylene and then introduced through the cover layer and left in the phosphating solution ^{at 90 ° C. for 5 minutes.} The panels were then pulled out through the cover layer, rinsed by immersion in cold running water and then in hot water containing 0.025% chromic acid and 0.025% phosphoric acid, and dried. The steel surfaces showed a typical, uniform, light gray, crystalline phosphate coating. These coatings did not reveal any uncovered areas that could be caused by adhering oil, and could easily be used as rust protection coatings or as a primer for oil, paint or varnish coatings. ^ao

Example 2

A phosphate coating solution of the following composition was prepared:

Weight percent

Zinc (Zn) 1.00

Sodium (Na) 0.20

Phosphate (PO ₄ ) 2.00

Nitrate (NO ₃ ) 1.36

Nitrite (NO ₂ ) 0.02

Non-ionic surfactant 0.50

(like in

Medium example 1)

Water rest

This solution was covered with a 12 mm thick layer of the hydrocarbon material used in Example 1, which contained a heat-stable red dye. This solution and the cap layer were then heated to 7O ⁰ C and held for 10 minutes at this temperature, so that a certain part of the surfactant could enter into the cover layer. Cold-rolled steel plates were degreased and treated as in Example 1, but the temperature of the phosphating solution was 70 ° C. Again, completely normal, uniform, light-gray, crystalline phosphate coatings were obtained, which were extremely suitable as a primer for oil, varnish or paint coatings.

Example 3

a carbon content of 0.55% and a diameter of 6.4 mm was in cold hydrochloric acid stained, rinsed in cold running water, inserted through the cover layer and Leave in the phosphating solution at 70 ° C for 5 minutes. Then the wire was through the Cover layer removed through, rinsed by immersion in cold running water and dried. The wire was covered with a uniform, light gray, crystalline phosphate coating and showed no bare spots due to adhering oil and smoothed out pull out to a smaller diameter using a soap lubricant.

Example 4

A phosphate coating solution of the following composition was prepared:

Weight percent

Manganese (Mn) 0.3

Iron (Fe) 0.1

Phosphate (PO ₄ ) 1.5

Nitrate (NO ₃ ) 0.1

Non-ionic surfactant 0.5

(like in

Medium example 1)

Water rest

This solution was with a hydrocarbon material whose flash point 180 ° C and whose Viscosity at working temperature was 5 cP, covered and heated to 95 ° C. Cast iron piston rings were degreased with trichlorethylene and passed through the cover layer into the phosphating solution brought in. After 15 minutes they were removed through the cover layer by immersion rinsed in cold running water and then in hot water and dried. The piston rings showed a typical iron-manganese-phosphate coating and no uncovered areas adhering oil could be recycled and the coatings could be used in a perfectly normal manner be, d. H. Lubricant hold and initial wear and tear during the running-in period Prevent internal combustion engines. Steel plates, nuts and bolts covered in this solution received normal phosphate coatings, which are used as anti-rust coatings and for sealing oil, Stain or paint were extremely suitable.

Example 5

A phosphate coating solution of the following was used. A phosphate coating solution of the following was used

Composition made: 55 Composition made:

Weight percent

Zinc (Zn) 0.8

Sodium (Na) 0.25

Phosphate (PO ₄ ) 3.0

Chlorate (ClO ₃ ) 0.9

Non-ionic surfactant 0.5

(like in

Medium example 1)

Water rest

This solution was covered with the used in Example 1, hydrocarbon material and heated as in Example 2 to 7O ⁰ C. Steel wire with

65 percent by weight

Manganese (Mn) 0.3

Iron (Fe) 0.1

Phosphate (PO ₄ ) 1.6

Nitroguanidine 0.1

Non-ionic surfactant 0.5

(like in

Medium example 1)

Water rest

This solution was covered with the hydrocarbon material used in Example 4 and how used in example 4 at 90 ° C.

Piston rings, plates, nuts, and bolts treated with it had similar ones Coatings like those treated in Example 4.

According to this procedure, the piston rings were adequately protected from corrosion during storage protected, and they had assumed a typical iron-manganese-phosphate coating, which one counteracts premature wear.

Example 6

A concentrated phosphate mixture was prepared with the following composition:

Weight percent

Manganese (Mn) 4.0

Iron (Fe) 0.25

Phosphate (PO ₄ ) 23.0

Nitrate (NO ₃ ) 1.5

Non-ionic surfactant

Mean 1.0

Hydrocarbon material (flash point 180 ⁰ C; viscosity at

21 ^° C: 112 cP) 16.0

Water rest

321 of this mixture, which were added to 423 l of water each, resulted in a phosphating bath, which had a cover layer that prevented splashing or smoke development. The same mixture was applied to refresh the bath during use. The surface-active The agent was a condensate of an alkylphenol with ethylene oxide.

Example 7

An oxalate coating bath was prepared with the following composition:

Weight percent

Manganese (Mn) 0.4

Nitrate (NO,) 1.0

Oxalate (COO) ₂ 3.5

Accelerator 0.3

Non-ionic surfactant 0.1

(like in

Medium example 6)

Water rest

The surfactant was the same as that used in the previous example.

This solution was heated to 70 ⁰ C and covered with a 12 mm thick layer of the hydrocarbon material used in Example. 1 Stainless steel wire was pickled in a mixture of nitric and hydrofluoric acids, rinsed in water and placed through the cover layer into the oxalate bath. After 5 minutes, the wire was removed through the cover layer, rinsed by immersion in cold running water and then in hot water and dried. The wire had a typical oxalate coating and showed no uncovered areas due to adhering oil, and the coating was able to counteract premature wear, ie hold lubricant and prevent wear during drawing to a smaller diameter.

Example 8

A phosphate coating bath was prepared with the following composition:

Weight percent

Zinc (Zn) 1.0

Phosphate (PO ₄ ) 2.0

Nitrate (NO.,) 1.5

Nitrite (NO ₂ ) 0.05

Anionic surfactant

Mean 0.2

Water rest

As the anionic surfactant, a secondary alkyl sulfate type agent has been used.

This solution was coated with a 12 mm thick layer of the hydrocarbon material used in Example 1 covered and heated to 70 ° C. Soft steel plates were degreased with trichlorethylene and introduced through the cover layer into the phosphating bath. After 3 minutes they were removed through the cover layer by immersion in cold running water and then rinsed in hot water and dried.

The plates showed a typical zinc phosphate coating with no uncovered areas, which was suitable To prevent corrosion under the protective coating if a part of this protective coating is mechanically damaged had been.

Example 9

A phosphate coating bath was prepared with the following composition:

Weight percent

Zinc (Zn) 0.8

Phosphate (PO ₄ ) 1.2

Nitrate (NO ₃ ) 1.3

Iron (Fe) '. 0.1

Cationic surfactant

Mean 0.2

Water rest

An alkyl trimethylammonium salt was used as the cationic surfactant.

This solution was coated with a 12 mm thick layer of the hydrocarbon stock material used in Example 1 covered and heated to 85 ° C. A basket containing small spring steel clips was made introduced through the cover layer into the phosphating solution. After 3 minutes the Clamps removed through the cover layer, transferred to a second basket and again introduced into the phosphating solution. This procedure was repeated until the brackets had been immersed a total of four times for 3 minutes each time. The brackets were subsequently in cold running water and then rinsed by immersion in hot water and in a centrifugal. joint dried. Then the clips were dipped in alcohol stain and dried in an oven.

According to this process, the spring clips were given a typical zinc-iron-phosphate coating and so were adequately protected from corrosion during use.

Example 10

A chromate passivation bath with the following composition was prepared:

Weight percent

Chromium trioxide 1.5

Phosphoric acid 1.0

Anionic surfactant

Mean 0.2

Water rest

ίο

A sodium salt of perfluoropentanesulfonic acid was used as the surface-active agent.

The solution was coated with a 12 mm thick layer of the hydrocarbon material used in Example 4 covered and heated to 100 ° C. Aluminum plates were immersed for 5 minutes at 98 ° C in a 3% metasilicate solution containing surfactant, degreased, in rinsed with cold water and introduced into the passivation bath through the cover layer. To one hour the plates were removed through the cover layer by immersion in cold running water and then rinsed in hot water and dried. That way coated panels were more resistant to corrosion than untreated panels.

The cover layer completely prevented splashing and evaporation of the solution during the Processing without affecting the coating. The solution used for degreasing can cover with a 12 mm thick layer of the same oil.

Example 11

A chromate passivation bath for magnesium with the following composition was prepared:

Weight percent

Sodium dichromate 8.0

Magnesium sulfate 4.0

Manganese sulfate 4.0

Anionic surfactant 0.5

(like in

Medium example 10)

Water rest

45

The solution was coated with a 12 mm thick layer of the hydrocarbon material used in Example 4 covered and heated to 100 ° C. Magnesium castings were made in 5 minutes long immersion in a 98 ° C 3% metasilicate solution containing surfactant, degreased, rinsed by immersion in cold running water and then through the cover layer introduced through into the passivation bath. After 30 minutes they were through the cover layer removed by immersion in cold running water and then in hot water rinsed and dried.

The cover layer completely prevented evaporation and splashing of the solution during the Treatment without affecting the coating.

From Example 6 it can be seen that this invention proposes, inter alia, concentrates that one after Can use dilution in aqueous baths for coating metal and which is an inert Contain liquid and an inorganic coating-forming substance.

40 The concentrates may be, and the proportion of inert fluid in the concentrate may be varied over a wide range liquid, pasty or solid preparations. The particular amount of inert liquid used in a given concentrate depends on the thickness of the cover layer required on the container in which the concentrate is to be applied and the concentration of active ingredients required, it being expedient to use on the surface of the solution in the In the container, an inert cover layer at least 10 mm thick must be provided. As stated above, surfactants can be incorporated into the concentrations in suitable amounts.

Example 12

A manganese phosphate concentrate for phosphating steel consists of:

Parts by weight

Manganese dihydrogen phosphate 84

Non-ionic surfactant
Medium (condensate from a long-chain fatty alcohol and ethylene oxide) 1

Hydrocarbon material
Flash point 180 ° C; viscosity
at 95 ° C: 5 cP) 15

A bath 122 χ 61 X 61 cm deep with a capacity of 4541 requires 45 kg of manganese dihydrogen phosphate. This amount is contained in 54.4 kg of concentrate along with 8.2 kg of hydrocarbon material and 0.54 kg of surfactant. 8.2 kg of hydrocarbon material correspond to 9.5 liters and, based on an area of 7500 cm ² , will thereby contain an inert layer about 15 mm thick. The bath was heated to 100 ° C. and degreased piston rings were used. After about 45 minutes the rings were removed and rinsed and found to have been heavily coated with phosphate.

Oxalate, chromate and sulfide concentrates can be obtained using comparable formulations or make other coating bath concentrates similar to the various in this specification disclosed methods can be applied.

Example 13

To produce 450 l of a treatment solution according to Example 12, 45 kg of the treatment solution in Example 12 indicated concentrate and 1 kg of the surfactant mentioned there used.

Titanium wire treated in this solution at 60 ° C. for 10 minutes received a good one Coating that, in conjunction with soap, supported the drawing process.

Claims (4)

Patent claims: 1. Bath for the production of non-metallic coatings, e.g. B. phosphate layers or oxide layers, on metallic objects with a liquid cover layer that is inert to the treatment solution, thereby identifying 409 538/496 records that the bath has a viscosity of less than at the working temperature 100 cP aliphatic hydrocarbon is covered and one at working temperature surfactant soluble in the treatment solution and in the cover layer in such an amount that emulsification between the cover layer and the treatment solution is excluded. 2. Bath according to claim 1, characterized in that the aliphatic hydrocarbon has a viscosity of 2 to 10 cP. 3. Bath according to claim 1, characterized in that it is a nonionic surface-active Contains funds. 4. Bath according to claim 1, characterized in that the surfactant from a quaternary ammonium compound. Considered publications:
German patents No. 843 791, 825 478,
677;
French patent specification No. 856 526. 409 538/496 3.64 © Bundesdruckerei Berlin