DE1496862B2 - PROCESS FOR GENERATING BLACK COATINGS ON AN ALUMINUM ALLOY OF TYPE 6063 BY ANODIC OXYDATION - Google Patents

Description

3 4

be, however, the general endeavor and phthalic acid, 7.78 g / l sulfuric acid and 4.1 g / l aluminum desire of the architects that the coating contained minium ions, the last of which consisted of one layer thicknesses are as small as possible. previous use of the electrolyte. That

It goes without saying that at higher current densities, the anodizing in the first stage was 2.9 A / dm ²

Maximum value of the voltage and then also the black 5 carried out over a period of 8.5 minutes,

Cover can be reached more quickly. until the maximum voltage of 60 V has been reached.

In general, it is advisable to measure the current density in

the start-up stage between 2.7 and 4.3 A / dm ² and the sierens at a constant voltage of 60 V up to

Voltage in the holding zone between 55 and 75 V for a total anodizing time of 35 minutes. Of the

to adjust. In particular, the electrolyte should be as described in Example 1,

τη u · mn / ι c it U ^ u ι · ■ α waxed and sealed. During the examination it was

70 to 100 g / l sulfophthalic acid and ■ _{teUt that ef mh a dense black anodi} .

Have 1 to 5 g / l sulfuric acid. _oxide film with a thickness of 0.0175 mm

There were further advantages of the method according to the invention.

are particularly the high quality of the 15 biscuits 1 3
Coatings that can be produced completely evenly on the aluminum objects and are extremely lightfast. A test piece made from an aluminum alloy. It is quite possible that the electrolyte contains 0.41% silicon, 0.24% iron, 0.04% copper, 0.61% normal impurities and also a certain amount of magnesium, 0.01% zinc and 0.01% titanium was containing amount of aluminum ions. 20 steps 1 to 4 described in Example 1 for the

Examples of anodizing according to the invention are prepared below.

proper procedures described. The object was then placed in a water-based

. -I immersed ₁ ring electrolyte maintained at 25 ° C

^Example: was and 95.5 g / l sulfophthalic acid, 9.9 g / l sulfur

An extruded article made from aluminic acid and contained 4.4 g / L aluminum ions. The anodi-

Alloy containing 0.4% silicon (in percent by weight) with a current density of 2.9 A / dm ²

0.24% iron, 0.01% zinc, 0.04% copper, 0.60% and was done after a time of 14 minutes

Magnesium, 0.01% titanium and normal impurities - reached the predetermined maximum voltage of 60 V,

The following steps were taken to prepare for anodizing, followed by anodizing with a constant chip: 30 voltage from 60 V up to a total anodizing time

1. 10 minutes in 5% NaOH solution was ^{7 6} 5 ^{minut n continued} f ^is at a. The object etched temperature of 54 ° C. ™ * ^Γαε washed and treated according to Example 1

2 Washed with water seals, and it was found that he seal one

i Cleaned by immersion in a 35 weight black anodic oxide coating of 0.0457 mm percent nitric acid solution. ^{35 prints had>}

4. Washed with water. Example 4

After the preparatory process steps, the aluminum alloy article with article is anodized by immersing it in an aqueous 0.40% silicon, 0.24% iron, 0.04% copper, 0.63% electrolyte containing 100 g / l sulfophthalic 40 mg, 0.01% zinc and 0.01% titanium was is acid and containing 5 g / l sulfuric acid and maintained on a by the steps 1 to 4 of example 1 for the Anodi temperature of 25 ⁰ C. Prepared for anodizing. The article was then as was started by a DC immersed with an anode in an aqueous electrolyte, the current density of 2.9 A / dm ² was passed was kept up at 25 ⁰ C and 100 g / l Sulfophthalsaure, a maximum voltage of 60 V was reached. The 45 5 g / l sulfuric acid and 0.05 g / l aluminum ion relaxation was continuously increased in order to maintain the current. The anodizing was done with an initial density of 2.9 A / dm ² . The maximum voltage current density of 2.9 A / dm ² carried out 12 minutes, of 60 V was reached after 14.8 minutes, and after this time the voltage had risen to 60 V, the anodizing at a constant voltage of around the current density became constant keep. Then 60 V up to a total anodizing time of 81.5 5 °, the anodizing was continued at a constant voltage for minutes. The article was removed from the electrolyte for a total of 60V anodizing time, washed with water and continued for 89 minutes. The article was immersed ge-10 minutes in an aqueous bath, which seals to wash and according to Example 1, and 96 ⁰ C was maintained and 0.6 g / l of sodium ligninsulfonate, it was found that he and 0.5 g of a black coating / l contains nickel acetate to seal the 55 by 0.0445 mm thick.
anodic oxide film formed. .

The result is an article with a stain - Example 5

black color free anodic oxide film and an aluminum alloy specimen with

Layer thickness of approximately 0.038 mm. 0.40% silicon, 0.24% iron, 0.04% copper, 0.63%

_B. . . 60 magnesium, 0.01% zinc and 0.01% titanium was used for

e 1 s 1 e ρ _anodizing according to the steps 1 to 4 of

An aluminum alloy article prepared with Example 1. Then the trial

0.40% silicon, 0.22% iron, 0.04% copper, 0.63% piece in an aqueous electro-

Magnesium, 0.01% zinc and 0.01% titanium was immersed in lytes containing 94.6 g / l sulfophthalic acid and

in accordance with the steps described in Example 1, 65 contained 4.5 g / l sulfuric acid. The specimen was

1, 2, 3 and 4 prepared for anodizing. at an initial current density of 2.9 A / dm ²

The item was then anodized in an aqueous 14.5 minutes, at which time the pre-

Electrolyte immersed at 25 ⁰ C, the 53.2 g / l sulfo-correct voltage of 60 V reaches. The anodi-

Sizing took a total of 75.8 minutes, after which the through 4 of Example 1 prepared for anodizing.

Test piece removed from the anodizing vessel and then it was placed as an anode in an aqueous electrode

washed and sealed according to example 1 lyten introduced containing 80.0 g / l sulfophthalic acid, 3.6 g / l

became. It was found that the alloy contained a sulfuric acid and 0.07 g / l aluminum ions,

black coating that was 0.0438 mm thick. 5 The anodizing was carried out with an initial current density of 4.3 A / dm ² until the preselected one

Examples maximum voltage of 72 V was reached, whereupon the

Anodizing process at 72 V up to a total

A specimen made of an aluminum alloy with an anodizing time of 45 minutes was made.

0.40% silicon, 0.24% iron, 0.04% copper, 0.66% io After washing and sealing, as in Example 1,

Magnesium, 0.01% zinc and 0.01% titanium have been found to have a black alloy

the anodizing according to steps 1 to 4 of example 1 has a coating, the thickness of which has not been determined,

prepared. The specimen was then turned into an.

25 ⁰ C held aqueous electrolyte immersed, .. Example »

of 101.2 g / l sulfophthalic acid, 4.85 g / l sulfuric acid 15 Another specimen made from the same alloy

contained, but only a small undetermined amount as in Example 7 was, as described in Example 1,

of aluminum ions. The anodizing was prepared with for the anodizing. The specimen was

an initial current density of 2.9 A / dm ² then immersed as an anode in an electrolyte, the

Carried out 16.8 minutes; at that time it was 80 g / l sulfophthalic acid, 3.6 g / l sulfuric acid and

reached a predetermined voltage of 60V. The anhydride contained 0.07 g / l aluminum ions. The anodizing

Odising was carried out with 60 V up to a total time of was carried out ^{at a temperature of 18 0 C.}

Carried out 67 minutes, after which the specimen from and at an initial current density of 3.9 A / dm ² ,

removed from the electrolyte, washed and corresponding until a predetermined voltage of 96 V was reached,

Example 1 was sealed accordingly. It was found about 10 minutes after the start of

that the specimen odizes a black coating of 25. Continue anodizing at approximately 96V

0.0400 mm thick. was up to a total anodizing time of

. . Carried out for 25 minutes. After washing and

Example 7 Sealing, as in Example 1, was found to have the

A specimen of the 6063 aluminum alloy had a 0.0175 mm black coating

or AlMgSi 0.5, corresponding to levels 1, was 30 thick.

Claims (6)

A method of this type has already been proposed (German Auslegeschrift 1260 266). Included 1. Method for producing black coatings succeeded in producing black coatings by anodic anodic oxidation on an aluminum alloy, ie without additional lacquer oxidation in an electrolyte that is more than 5 ren, spraying or the like, only with Alu-10 g / l sulfophthalic acid and sulfuric acid or a minium alloy of the type 6061 (AA) or AlMgSi ₁ sulfate, with a current density in the size (DIN) and type 7075 (AA) or AlZnMgCu 1.5 order of 1 to 10 A / dm ² and a voltage (DIN). In the case of alloys of the type 6063 (AA) or in the order of magnitude of 10 to 100 V, AlMgSi 0.5 (DIN), which are far more common and can be better used for many purposes characterized by the application, an alloy of the Type 6063 or AlMgSi 0.5 only a matt bronze color can be achieved. Alloy with essentially: stanchions of this type are mainly used for panels, η ο u; * r \ fo / c; i; ™ \ „v. Frames and cladding of walls, doors and Κ) ₉ Δ Dia \ J, O / _o O1HC1UII1,. V,., R ι ι · ι up to 0 35 y iron windows were used, so that it was previously necessary • Up to 010 V KuDfer ^{15 d} ' ^{ese can} also be painted black if required up to 010 V manganese ^{na (* e 'its} blackening of such parts exist. 0 45 Biso 97 Magnesium ^{The Erfindun} g ^{therefore lie the} task gt underlying 0 up to 1V chrome ^{'m' t} P ^ra ktisch same means on alloys up to 01 / zinc ' ^des ^ ^V P ^S 6063 or AlMgSi 0.5 a black over- up to 01V titanium ^{20 to} & ^by anodic oxidation, and that too up to 0.15% other alloying agents, to be produced at normal temperatures. Remainder aluminum besides permissible contamination. The invention now consists in the application of a Cleaning such an alloy with essentially: (^ .., ",",, "._, ·, 0.2 to 0.6% silicon, with the proviso that in the electrolyte 25 _{up to} 0.35% proteins, 25 to 150 g / l sulfophthalic acid and up to 0.10% copper, 0.1 to 15 g / l sulfuric acid are used, up to 0.10% manganese, ,, ", ..,., ... . 0.45 to 0.9% magnesium,
and that for the anodizing program - ■ - ■ up to 0 17 chromium Start-up stage with increasing voltage at im 30 'up to 017 zinc' substantial constant current density between 1.6. up to o'l V titanium and 5.4 A / dm * and a holding stage in the essential _'to JJL / _{ande' re Leg} ierungsbildner ' lichen constant ^ tension in the range of about the _{remainder of aluminum in addition to excessive} impurities 25 to 100 V at the maximum value of the start-up level "" "" = " is chosen. - - 35 ⁸ g'j 2. The method according to claim 1, characterized in that the electrolyte \ records that the current density in the start-up stage ¹ · ■ ''^; _{25 to 150 j {} sulfophthalic acid and ^! between 2.7 and 4 3 A / dm ² , _{Ql to 15; 1} sulfuric acid is used, 3. The method according to claim 1 or 2, characterized characterized in that the voltage in the holding zone is 4 ° and that for the anodizing program an intermediate 55 and 75 V is held. speed level with increasing voltage at essentially 4. The method according to any one of the preceding borrowed constant current density between 1.6 and .. claims, characterized in that the temperature 5.4 A / dm ² and a holding stage with essentially temperature of the electrolyte between 7.2 and 29.4 ° C constant voltage in the range of about 25 to 100 V f is maintained. 45 is selected at the maximum value of the start-up level. ^ - 5. Method according to one of the preceding To achieve opaque, d. H. milky oxide layers Claims, characterized in that it is an electrolyte on aluminum objects according to the Emataltrolyte with procedures already known, with an initial ™ λ. · Inn / 1 ο it i_ ι. ι ·· j current density from 2 to 3 A / dm ² up to a constant 70 to 100 g / l sulfophthalic acid and _{5o voltage of 120} γ _to anodize and then 1 to 5 g / l sulfuric acid - y _{he voltage until the end of} the anodizing is used. · Keep '' 'gangs constant, after about 20 to 40 6. Procedure after one of the preceding minutes has been reached. The electrolyte temperature is claims, characterized in that it is 50 to 70 ° C. , 0508 mm coloring is also carried out on the above-mentioned alloy type. '· , Can be achieved if the above measures .'K ¹ V ,? ■ are taken, although normal temperatures, especially especially between about 4.2 and 29.4 ⁰ C, applied Turn 60, d. H. no elevated temperatures required are. In addition, it is possible to use black The invention relates to a method for producing coatings in a relatively short time. Production of black coatings on an aluminum The surprising thing is that these alloys are relatively thin due to anodic oxidation in an elec- tric black coatings. The trolyte, which contains more than 10 g / l sulfophthalic acid and 65 anodizing, can therefore be terminated with a current temperature even at such low sulfuric acid or sulfate temperatures when the density is in the order of 1 to 10 A / dm ² and a layer thickness of about 0.0076 to 0.0508 mm, a voltage of the order of magnitude of 10 to 100 V. Of course, the layer thickness can also be greater