CS261832B1 - Method for aluminium oxide electrolytic colouring onto bronze and black shades - Google Patents

Abstract

A method of electrolytic or oxide dyeing aluminum is that it is anodically oxidized aluminum is stained by action alternating patch 7 to 12 volts in solution with containing 60 to 120 kg. m * 3 nickel sulfate heptahydrate, 15 and 25 kgm * 3 chloride nickel hexahydrate, 15 to 30 kg. . m 3 of boron acid and 15 to 30 kg i m-3 5-sulfo-1,3-benzimidicarboxylic acid. The solution temperature is 21 + 5% pH of the solution is 4.5 to 6.0. The dyeing time is 60 to 1080 seconds according to the desired color shade. The counter electrodes are nickel. coloring aluminum oxide is good mechanical resistance to wear, excellent color shade h and light and corrosion resistance.

Description

The method of electrolytic or dyeing of aluminum oxide is characterized in that the anodized oxidized aluminum is dyeed by alternating a 7-12V alternating charge in a solution containing 60-120 kg. m * ³ nickel sulfate heptahydrate, 15 and 25 kgm * ³ nickel chloride hexahydrate, 15 to ² 30 kg.

. m- ³ of boric acid and 15 to 30 kg of im- ³ of 5-sulfo-1,3-benzeridicarboxylic acid.

The solution temperature is 21 + 5% pH of the solution is 4.5 to 6.0. The staining time is 60 to 1080 seconds, depending on the desired color shade. The counter electrodes are nickel. The colored aluminum oxide is characterized by good mechanical abrasion resistance, excellent color shade stability and light resistance and corrosion resistance.

281832

The invention solves the method of electrolytic dyeing of aluminum oxide to bronze and black color shades as a method of protective-decorative finish of aluminum objects to reproducible color shades with high color fastness.

The present method of color coating of aluminum consists in anodizing oxidation and subsequently coloring the formed aluminum oxide with an adsorption method in aqueous dye solutions. This method of coloring of aluminum guarantees low stability of the color shade, i.e. saturation, and the color shade of the surface varies over time, especially in light shades. Another possibility of color coating the aluminum lies in anodic oxidation and subsequent coloration of the formed aluminum oxide electrolytically in metal salt solutions. Previously known methods of electrolytic dyeing of aluminum to bronze to black color shades use baths, the main component of which are precious metals, e.g. silver, respectively. selenium-deficient substances and so-called bivalent tin baths. The tin salt baths have low stability to the air oxygen through which they are oxidized, and also the low pH value of these baths causes the dissolution of the aluminum oxide, thereby reducing the corrosion resistance of the articles.

Said disadvantages of the known processes are solved by the method of electrolytic dyeing of aluminum oxide to bronze, brown to black color shades, which is based on the fact that anodically oxidized aluminum articles having an aluminum oxide thickness of 12. 10 ~ ⁶ to 40. 10 ^rt m are stained with alternating current in a solution of 60 to 120 kg.

. m ³ of nickel sulphate heptahydrate, 15 to 25 kg. m ^-3 nickel chloride hexahydrate, 15 to 30 kg. add ³ 5-sulpho-1,3-benzenedicarboxylic acid dichloride. The working temperature of the bath is 20 + 2 ° C for reproducible results. If there is no reproducibility requirement, the bath temperature is 21 + 5 ° C. The pH of the electrolyte is 4.5 to 6.0. The auxiliary electrodes are nickel. For coloring the aluminum oxide in the electrolyte according to the invention, alternating voltages on the electrodes of 7 to 12 V are required, depending on the arrangement of the electrolyser, the time course of the alternating voltage and the desired color shade. It is a characteristic of the dyeing process according to the invention that the dyeing intensity increases with the dyeing time from light bronze through medium bronze, dark brown to black. The stage of the desired color shade is a dyeing time of 60 to 1,080 seconds.

The advantage of the process of electrolytic dyeing of aluminum oxide to bronze to black fan color shades according to the invention is to obtain mechanically quality surfaces with uniform coloration and good reproducibility of the color shade. The bath is stable, environmentally friendly. Changes in the concentration of bath components during the operation of the bath are mainly caused by the yield of the solution on the objects; frequent check by analysis.

These decor surfaces are suitable for a wide range of applications in consumer goods and construction.

Example 1

Anodised aluminum with alumina thickness 18. 10 ⁶ m is electrolytically stained by the alternating voltage of 8-Volts in-solution containing 80 kg. m- ³ nickel sulfate heptahydrate, 22 kg. m ³ of non-ferrous chloride hexahydrate, 25 kg. . m ³ of boric acid and 18 kg. m ^-3 of 5-sulfo-1,3-benzenedicarboxylic acid at an electrolyte temperature of 24 ° C and a pH of 5.2. The counter electrodes are nickel. At a coloring time of 150 seconds, a light-colored, bronze hue appears on the aluminum surface.

• Go to la d .2;

.Anodically oxidized aluminum with a thickness of. -xidu alumina 25th-.- ^A 10 m was electrolytic treatment stains AC voltage of 12 V _'solution; containing 110 kg. m ³ of nickel sulphate heptahydrate, 15. kg. m ³ nickel chloride hexahydrate, 30 kg. m. ³ boric acid and 20 kg. m ³ of 5-sulfo-1,3-benzenedicarboxylic acid at. an electrolyte temperature of 20 ° C and its pH = 5.8. The counter electrodes are nickel. At a coloring time of 900 seconds, the aluminum object. color n & black .. ·

Claims (1)

Method of electrolytic dyeing of aluminum oxide to bronze and black color shades with uniform appearance, stable and reproducible shade, characterized in that the anodized aluminum article having an aluminum oxide thickness 12. 10 ⁶ to 40. 10 ^µm is electrolytically stained by alternating 7 to 12 volts in a solution containing 60 to 120 kg. m ^{3 3} SOVYNALEZU wound nickel heptahydrate, 15-25 kg. m ^-3 nickel chloride hexahydrate, 15 to 30 kg. m ³ of boric acid and 15 to 30 kg. m ^-3 5-sulfo-1,3-benzenedicarboxylic acid at an electrolyte temperature of 21 + 5 ° C, an electrolyte pH of 4.5 to 6.0, for 60 to 1080 seconds, according to the desired color shade.