JPS594519B2 - Electrolytic coloring method for aluminum or its alloys - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention applies to colors ranging from bronze to black, blue, yellow,
This invention relates to an electrolytic coloring method for aluminum or its alloys that can be colored orange, purple, green, and red.

There are various methods for coloring the anodic oxide film of aluminum or its alloys, but they can be broadly classified into dyeing methods, natural coloring methods, electrolytic coloring methods, and electrolytic coloring methods. The dyeing method allows dyes to be adsorbed into the fine pores of the anodic oxide film, so you can freely select the color, but the light resistance is poor, the natural coloring method is expensive because it uses a special alloy, and the electrolytic coloring method is expensive because it uses a special alloy. It is expensive because it uses organic acids and color matching is difficult. Compared to these coloring methods, the electrolytic coloring method uses metal salts5.
Although there is a problem with coloring, it is now becoming the mainstream coloring method because it has good light fastness and is inexpensive. However, the colors that can be colored by this electrolytic coloring method are limited to colors ranging from brown to black, and it was not possible to color the 10 colors of blue and purple.

The present invention provides electrolytic coloring of aluminum or its alloys in colors ranging from bronze to black, blue, yellow, orange,
Can be colored purple, green, and red.

The present invention will be explained in detail below. 15 Aluminum or its alloy that has been subjected to a conventional pretreatment is subjected to a first anodization treatment in a sulfuric acid bath, an oxalic acid bath, or a chromium trioxide bath, and then a second anodization treatment is carried out in an organic acid bath.

The voltage during the second anodization is an important factor that determines the coloring during the next step of alternating current electrolytic coloring. In other words, if the voltage during the second anodization is low, the color is colored from bronze to black, or from red to maroon to black, using AC electrolysis, and then the second anodization is carried out. When the voltage is high, green, blue or purple coloring can be achieved by 25 minutes of alternating current electrolysis in a short period of time. If the voltage during the second anodization is too high, the anodic oxide film is likely to be destroyed because a high voltage is required during AC electrolytic coloring. If the first anodic treatment is not carried out, a high voltage will be applied to the aluminum 30 or its alloy base or the anodic oxide film, and the aluminum or its alloy base or the anodic oxide film will likely be damaged in the form of small dots, which is impractical.

Since the first anodization is performed, the subsequent second anodization takes only a short time, the organic acid bath 35 suffers little aging, and the amount of electricity used is low, making it economical. Unless the second anodization is performed at a higher voltage than the first anodization, green, blue, or purple coloring will not occur. The organic acids used in the second anodization are carboxylic acids, oxycarboxylic acids, ketocarboxylic acids, amino acids, and aromatic sulfonic acids.

The metal salt dissolved in the electrolytic bath for AC electrolytic coloring treatment is tin,
These are nickel, manganese, cadmium, iron, cobalt, aluminum, zinc, magnesium, zirconium, and chromium salts. The following table shows the relationship between organic acids, color shading, and color number. By using two or more organic acids in the second anodization, the color tone, density, coloring uniformity, etc. can be improved more than when one is used alone.

For example, when anodizing with a sulfuric acid bath and then electrolytically coloring with a malonic acid bath alone, the coloring is weak and the coloring uniformity is poor, but when anodizing with a mixed bath of malonic acid and cresol sulfonic acid, the coloring becomes darker and the coloring uniformity is poor. gets better. In addition, after anodizing in a sulfuric acid bath, anodizing in a lactic acid (6 (!)) bath alone and electrolytically coloring results in weak coloring, but a mixed bath in which a small amount (0.5%) of sulfuric acid is added to this lactic acid bath alone gives a light coloring. The color becomes darker when anodized and electrolytically treated. In addition to alternating current, the coloring treatment using alternating current electrolysis can use a waveform of current that has the same effect as alternating current, such as an alternating current superimposed current whose polarity changes periodically and has an alternating current component.

Next, examples of the present invention will be shown. Example 1 An aluminum plate (AlO5O) subjected to a conventional pretreatment was heated in a 40 g/l oxalic acid bath at a bath temperature of 25°C and a direct current of 25V13.
After anodizing for 0 minutes, anodizing in a 209/l phenolsulfonic acid bath at a bath temperature of 22°C and 50V DC for 15 minutes, and washing with water, stannous sulfate 59/11 nickel sulfate 209/11 sulfuric acid 59/11 cresol sulfone acid 59
When AC electrolysis is carried out in an electrolytic bath consisting of 31 °C, AC 15, and a carbon rod as a counter electrode, the aluminum plate becomes brown in about 7 minutes, amber in about 10 minutes, blue in about 11 minutes, and orange in about 18 minutes. It turned purple in about 19 minutes and turned green in about 21 minutes.

Example 2 The aluminum plate of Example 1 was anodized in a 1759/l sulfuric acid bath at a bath temperature of 20°C and a direct current of 15 V for 30 minutes.
09/l toluenesulfonic acid bath, bath temperature 22℃, DC 5
After anodizing for 0.5 minutes and washing with water, stannous sulfate 59
/11 nickel sulfate 209/11 sulfuric acid 59/11 cresol sulfonic acid 59/l in an electrolytic bath at a bath temperature of 31°C.
When AC electrolysis is carried out using AC 25 and a carbon rod as the counter electrode, the aluminum plate becomes yellow in about 3 minutes, light purple in about 5 minutes, light green in about 8 minutes, light purple in about 10 minutes, light ocher in about 13 minutes, It turned pale blue in about 15 minutes, and light green in about 18 minutes.

Example 3 The aluminum plate of Example 1 was 175f! /l sulfuric acid bath at a bath temperature of 20°C and direct current for 15, 30 minutes, then 2
Bath temperature 20 in an electrolytic bath of 0 f1/l cresol sulfonic acid.
After anodizing at 50°C for 5 minutes and washing with water, stannous sulfate 59/11 nickel sulfate 209/l, sulfuric acid 59/l
l, an electrolytic bath consisting of 59/l of cresol sulfonic acid,
When electrolyzing with AC using a carbon rod as a counter electrode at a bath temperature of 32°C and AC 15V, the aluminum plate becomes brown in about 8 minutes, black in about 10 minutes, amber in about 12 minutes, blue in about 14 minutes, green in about 18 minutes, It turned yellow in about 20 minutes and turned purple in about 22 minutes.

Example 4 The aluminum plate of Example 1 was anodized in a 309/l chromium trioxide bath at a bath temperature of 21°C and DC 25V for 40 minutes, and then in a 209/l phenolsulfonic acid bath at a bath temperature of 27°C.
, DC 38, after anodizing for 5 minutes and washing with water, stannous sulfate 5f! /l, nickel sulfate 209/11 sulfuric acid 59/l
Electrolytic bath consisting of 59/l of 11 cresol sulfonic acid bath temperature: 30°C, AC electrolysis using a carbon rod as a counter electrode, the aluminum plate becomes brown in about 6 minutes, dark red in about 10 minutes,
It turned blue in about 12 minutes, orange in about 15 minutes, green in about 19 minutes, and purple in about 22 minutes.

Example 5 The aluminum plate of Example 1 was anodized in a 1759/l sulfuric acid bath at a bath temperature of 20°C and a direct current of 15 V for 130 minutes.
0f! /l of phenolsulfonic acid bath at a bath temperature of 23°C and a direct current of 50°C for 5 minutes, and after washing with water, 59/l of stannous sulfate, 209/l of nickel sulfate, 59/11 of sulfuric acid, and 5f of cresolsulfonic acid! ! When AC electrolysis is performed in an electrolytic bath consisting of 31° C./l with a carbon rod as the counter electrode, the aluminum plate becomes brown in about 10 minutes, black in about 13 minutes, dark blue in about 14 minutes, and blue in about 16 minutes. , orange in about 26 minutes, red in about 28 minutes, purple in about 30 minutes, green in about 34 minutes,
It turned yellow in about 36 minutes.

Example 6 In Example 5, after anodizing under the same conditions, AC electrolysis was performed under the same conditions except that the same amount of magnesium sulfate was used instead of nickel sulfate, and the aluminum plate was
Brown at 0 minutes, blue at about 14 minutes, orange at about 20 minutes, about 22
It colored red in minutes, purple in about 24 minutes, and green in about 28 minutes.

Example 7 After anodizing under the same conditions as in Example 5, AC electrolysis was performed under the same conditions except that the same amount of ferrous sulfate was used instead of nickel sulfate, and the aluminum plate turned brown in about 10 minutes. It turned black in 12 minutes, dark blue in about 14 minutes, blue in about 16 minutes, orange in about 26 minutes, red in about 32 minutes, and purple in about 36 minutes.

Example 8 After anodizing under the same conditions as in Example 5, AC electrolysis was performed under the same conditions except that the same amount of cobalt sulfate was used instead of nickel sulfate. The aluminum plate turned brown in about 8 minutes and turned brown in about 12 minutes. Dark red, blue in about 15 minutes, orange in about 25 minutes, red in about 28 minutes, purple in about 30 minutes, about 3
It turned green in 3 minutes.

Example 9 After anodizing under the same conditions as in Example 5, AC electrolysis was performed under the same conditions except that the same amount of zinc sulfate was used instead of nickel sulfate.
Brown in minutes, black in about 15 minutes, dark brown in about 17 minutes, approx. 19 minutes
It turned blue in minutes, orange in about 30 minutes, red in about 38 minutes, purple in about 42 minutes, and green in about 45 minutes.

Example 10 After anodizing under the same conditions as in Example 5, AC electrolysis was performed under the same conditions except that the same amount of manganese sulfate was used instead of nickel sulfate. The aluminum plate turned brown in about 10 minutes and turned brown in about 12 minutes. It turned blue in about 14 minutes, yellow in about 17 minutes, orange in about 19 minutes, purple in about 22 minutes, green in about 25 minutes, and red in about 28 minutes.

Example 11 If AC electrolysis is carried out under the same conditions as in Example 5 except that the same amount of cadmium nitrate is used instead of nickel sulfate,
The aluminum plate turns brown at about 10 minutes, amber at about 13 minutes, blue at about 15 minutes, green at about 22 minutes, orange at about 25 minutes, and about 3
It turned red in 3 minutes and turned purple in about 36 minutes.

Example 12 When AC electrolysis was carried out under the same conditions as in Example 5 except that the same amount of aluminum sulfate was used instead of nickel sulfate, the aluminum plate became brown in about 8 minutes, dark brown in about 12 minutes, and
It colored blue in about 14 minutes, yellow in about 20 minutes, orange in about 24 minutes, red in about 26 minutes, purple in about 28 minutes, and green in about 31 minutes.

Example 13 When AC electrolysis was carried out under the same conditions as in Example 5 except that the same amount of chromium sulfate was used instead of nickel sulfate, the aluminum plate turned brown in about 6 minutes, dark blue in about 8 minutes, and blue in about 10 minutes. It turned yellow in about 14 minutes, orange in about 16 minutes, red in about 18 minutes, purple in about 20 minutes, and green in about 22 minutes.

Example 14 When AC electrolysis was carried out under the same conditions as in Example 5 except that the same amount of ammonium zirconium tetrasulfate was used instead of nickel sulfate, the aluminum plate turned brown in about 7 minutes, dark blue in about 9 minutes, and dark blue in about 11 minutes. It was colored blue, yellow in about 18 minutes, orange in about 20 minutes, red in about 22 minutes, purple in about 24 minutes, and green in about 26 minutes.

Example 15 The aluminum plate of Example 1 was anodized in a 1759/l sulfuric acid bath at a bath temperature of 20°C and a direct current of 15 minutes for 30 minutes, and then at 60°C.
After anodizing at room temperature, DC 40 V, and water for 7 minutes in an electrolytic bath of 9/l lactic acid, stannous sulfate 51/l) nickel sulfate 15 y/l) sulfuric acid 5 y/l) cresol sulfonic acid 109/l When AC electrolysis is performed in an electrolytic bath with a bath temperature of 30°C and a carbon rod at 25 V as a counter electrode, the aluminum plate becomes pale ocher in about 1 minute, yellow in about 3 minutes, pale purple in about 5 minutes, and pale in about 10 minutes. Colored red.

Example 16 The aluminum plate of Example 1 was anodized in a 1759/l sulfuric acid bath at a bath temperature of 20°C and a direct current of 15 V for 130 minutes, and then
In an electrolytic bath of 0θ/l levulinic acid at room temperature, DC 30V, 6
After anodizing for a minute and washing with water, stannous sulfate 5 y/l,
Nickel sulfate 15g/l, sulfuric acid 5g/l) Cresol sulfonic acid 10y/l electrolytic bath, bath temperature 31°C, AC 25V
When electrolyzing with alternating current using a carbon rod as the counter electrode, the aluminum plate turns brown in about 1 minute, pale blue in about 2 minutes, orange in about 3 minutes,
It turned green in about 5 minutes.

Example 17 The aluminum plate of Example 1 was anodized in a 401/l oxalic acid bath at a bath temperature of 25°C and a direct current of 25 V for 140 minutes, and then electrolytically dissolved in 509/l of levulinic acid at a bath temperature of room temperature and a direct current of 5 V.
0V) After anodizing for 6 minutes and washing with water, 5 minutes of stannous sulfate
9/1, nickel sulfate 159/111, sulfuric acid 5g/1, cresol sulfonic acid 109/l in an electrolytic bath at a bath temperature of 29°C.
When AC electrolysis was performed at 25 V AC using a carbon rod as the counter electrode, the aluminum plate became pale purple in about 1 minute, pale yellow in about 3 minutes, pale green in about 7 minutes, and pale red in about 10 minutes.

Example 18 The aluminum plate of Example 1 was anodized in a 30 f1/l chromium trioxide bath at a bath temperature of 26°C and a direct current of 25 V for 40 minutes, and then in a 509/l levulinic acid electrolytic bath at a bath temperature of room temperature. DC 40V) After anodizing for 6 minutes and washing with water, stannous sulfate 5g/1, nickel sulfate 159/11 sulfuric acid 5y
/l) When AC electrolysis is performed in an electrolytic bath containing 10 g/11 of cresol sulfonic acid at a bath temperature of 32°C and AC 15 V using a carbon rod as a counter electrode, the aluminum plate becomes blue in about 5 minutes, purple in about 10 minutes, and black in about 20 minutes. Colored.

Example 19 The aluminum plate of Example 1 was anodized in a 175 g/l sulfuric acid bath at a bath temperature of 20°C and a DC 15 V) for 30 minutes, and then in a 501/l glycine electrolytic bath at room temperature and a DC 50 V).
After anodizing for 6 minutes and washing with water, stannous sulfate 51/l)
Electrolytic bath of nickel sulfate 151/l) sulfuric acid 51/l) cresol sulfonic acid 101/l, bath temperature 32°C, AC 25V
When electrolyzed with alternating current using a carbon rod as the counter electrode, the aluminum plate turned pale brown in about 1 minute, yellow in about 3 minutes, and purple in about 5 minutes.
It turned blue in about 7 minutes and turned yellow in about 10 minutes.

Example 20 The aluminum plate of Example 1 was anodized in a 1751/l sulfuric acid bath at a bath temperature of 20°C and a DC 15V for 130 minutes, and then
After anodizing for 5 minutes at room temperature and 50 V DC in an electrolytic bath of 0.09/l succinic acid, and washing with water, 5 g of stannous sulfate/11 nickel sulfate 151/l) sulfuric acid 5 y/l) Cresol sulfonic acid 109/l The electrolytic bath has a bath temperature of 32°C and an AC of 2
When AC electrolysis was carried out at 5V with a carbon rod as the counter electrode, the aluminum plate became pale ocher in about 1 minute, pale blue in about 3 minutes, pale green in about 5 minutes, and pale purple in about 10 minutes.

Example 21 The aluminum plate of Example 1 was anodized for 40 minutes in a 401/l oxalic acid bath (bath temperature 25°C, DC 25 V), and then in a 50 g/l malonic acid or succinic acid electrolytic bath at a bath temperature of Room temperature, DC 30V) After anodizing for 6 minutes and washing with water, stannous sulfate 5y/11 nickel sulfate 151/l) sulfuric acid 51
/1, When AC electrolysis is performed in an electrolytic bath consisting of 101/l of cresol sulfonic acid at a bath temperature of 31°C and AC 15 V using a carbon rod as a counter electrode, the aluminum plate turns pale red in about 3 minutes, approx.
It turned brown in minutes and turned black in about 15 minutes.

In Examples 1 to 5, 8, 15, 16, 18, 19,
The following table shows the coloring of aluminum in Comparative Examples 1 to 10 when no anodization with an organic acid is performed.

As is clear from these comparative examples, if anodization with an organic acid is not performed, the number of colors decreases.

Claims (1)

[Claims] 1 Aluminum or its alloy in a sulfuric acid bath, an oxidized acid bath,
or anodized in a chromium trioxide bath, then carboxylic acid,
After anodizing in an electrolytic bath containing one or more of oxycarboxylic acids, ketocarboxylic acids, amino acids, aromatic sulfonic acids, tin salt and nickel, manganese, cadmium, iron, cobalt, aluminum, zinc, magnesium,
An electrolytic coloring method for aluminum or its alloys, in which alternating current electrolysis is carried out in an electrolytic bath in which one or more metal salts of zirconium and chromium are dissolved.