TW295605B - Electrolytic process for coloring aluminum and aluminum alloys - Google Patents

Abstract

A method for electrolytically coloring aluminum or aluminum alloys comprising the steps of: (1) degreasing with 30% nitric acid; (2) rinsing; (3) etching with 10% NaOH;(4) rinsing; (5) neutralization with 10% nitric acid; (6) rinsing; (7) anodetreatment in 180 g/liter sulfuric acid solution under 18 deg.C with a direct current of 17V for 25 minutes; (8) rinsing; and finally (9) electrolyticcoloring treatment with alternating current of current density of 0.4 to1.4 A/dm2 under room temperature, the composition of the treatment bath being H3BO3 20 to 50 g/l, ZnSO4-7H2O 30 to 90 g/l, SnSO4 0.5 to 4.5 g/l, H2SO4 10 to 50 g/l and stannous sulfate stabilizer 1 to 15 g/l, and the stannous sulfate being selected from poly-functional carboxylic acid or aromatic carboxylic acid and sulfonic acid by which Sn4+ may be reduced to Sn2+.

Description

295605 V. Description of the invention (1) The present invention is an electrolytic color development method related to the electrolysis of aluminum or aluminum alloys into gray series: in various aluminum or aluminum alloys, the electrolytic color development method using alternating current is used to produce gray Among the series of methods, alloys using metal salts of zinc and tin are the easiest to operate and control. Due to the great difference between the oxidation-reduction half-potentials (E °) of zinc and tin Zn + 2 + 2e_ 2 Zn E ° 2 -0.7628, Sn + 2 + 2e_ = Sn Κ〇 二 · 〇 · 136 If used directly at the cathode electrolysis color To produce alloys in the process, there are difficulties in the method. In order to solve this difficulty, we are toward 1. Raising the redox half potential of tin (Sn + 2); 2. Decreasing the redox half potential of zinc (CZn + 2); 3. Increase the ion concentration ratio of zinc and tin to overcome it. In the electrolytic color development method using zinc-tin alloys, there is the British patent C Brit · pat. 14 08859), because the use of stannous sulfate is more than 5 grams / liter, so the PH must be controlled at 1 ~ 1. Between 5 and 5 can produce gray, but due to the adjustment of PH, the electrolytic degree of the electrolyte [Conduct i vity; ^ -high, and the use of this method band produces 1. The surface hard film produces softening splashes; 2. Color depth Quick changes are not conducive to control in production. There are difficulties in production. The Ministry of Economic Affairs of the Central Committee of the Central Committee of the Ministry of Economic Affairs and Labor Cooperation Du Yin ^ The biggest feature of this method is that after the use of boric acid and zinc sulfate to form the wrong salt of zinc, the redox half potential of zinc (CZn + 2) is reduced, and The Zn + 2 / Sn + 2 ion concentration ratio is above 8: 1, and the use of too many drugs should be minimized, making the electrolyte easy to embed and control. Since boric acid has its solubility limitation, this method uses boric acid as the base point to find the usage of other components. · The solubility of boric acid is about 50 g / L at room temperature, but for the convenience of operation, most of the From 30 to 40, the first page of this paper scale is applicable to the Chinese National Standard (CNS) Λ4 specification (2! () ≫ < 297 male sewing) Printed by the Ministry of Economic Affairs Central Standard Falcon Bureau Employee Consumer Cooperatives A7 B7 V. Description of the invention (2) g / l. The zinc sulfate (ZnS04 · 7Η2〇) is calculated from the boric acid concentration. The use concentration is between 50 and 70 g / l. If the zinc sulfate concentration is increased, it will not help the gray hair color, but will increase the cost. The waste of the above, and then by increasing the concentration of zinc / tin, it is known from the Λ test that the concentration of stannous sulfate should be below 5 grams / liter, and only a gray series of electrolytic aluminum or aluminum can be easily produced in production alloy. In order to increase the throwing power (Throwing power) during electrolytic hair coloring, we use sulfuric acid CH2S04) »In order to make the current distribution in the electrolytic hair color uniform, from the experiment, we know that the sulfuric acid concentration should be between 10 ~ 50 g / l, If it is less than 11) g / L, it will produce: 1. Coloring is not easy; 2. Cathode efficiency is too low; 3. Coloring is uneven; 4. Coloring time is too long, if it is higher than 50 g / L, it will produce: 1. Oxidation Loosening film; 2. Fading after hair color before washing. Because stannous sulfate is used to avoid the stability of tin (Sn + 2), stannous sulfate stabilizers are used, such as the polybasic organic acid CP〇ly base Carboxylic Acid) or aromatic organic acids (Aromatic Carboxylic Acid) and sulfonic acid (Sul f on ic Acid), its concentration is about 4 g / L or less. Under operating conditions, the temperature can be operated at room temperature. The current density should be between 0.4 and 1.4A / dm2 after multiple tests. If it is lower than 0.4A / dm2, the production time will be affected due to the long color development time. If it is more than 1.4A / dm2, it will often cause the hard film to break. Examples: Example 1. Aluminum or aluminum alloy: 1. Degreasing: degreasing in 30% nitric acid, washing with rubbing water; 2. Etching: Etching with 10% sodium hydroxide, washing with rubbing water; 3. Neutralization: Neutralized with 10% nitric acid, washed with water; and 4. Anodic treatment ·· 18〇g / liter of sulfur This paper standard is applicable to Chinese national standard (CNS > Λ4 specification (210X297 gong)) Second shell A7 H7 Qimanbei lost愫!?-局., = ^ _ Poverty-reduction cooperative printing A. Description of the invention (3) 18 ° c DC voltage 17 V in acid solution, anodizing for 25 minutes, washing with water, etc. After the above previous treatments, the following The composition and method of the electrochromic bath solution, and the color development using alternating current: The composition of the bath solution: Boric acid (h3bo3) 40 g / l zinc sulfate CZnS04 · 7Η20) 60 g / l sulfuric acid ch2so4) 25 g / l subsulfuric acid Tin (SnS04) 2.5 g / l tartaric acid (H00CCCH0H) 2 C00H) 1. 5 g / l color bar #: Corresponding electrode: carbon electrode temperature: 25 ° C current density: (). 8A / dm2 time: 9 minutes coloring Appearance: presents a beautiful gray appearance Example 2. The pretreatment process is the same as Example 1. Composition of bath solution: Boron 30 g / l zinc sulfate 50 g / l stannous sulfate 3 g / l sulfuric acid 30 g / l l Yellow 1 salicylic acid (Su 1 fosa 1 icylic Acid) 3 g / l Hair color condition: Corresponding electrode: stainless steel Electrode temperature: 25 ° c Current density: 0.7A / dm2 Time: 10 minutes, this paper uses the middle threshold threshold standard year (CNS) AWUS (2 丨 Οχ 2 () 7 Gongqi) Third page A7 B7 V. Description of invention ( 4) Coloring appearance: presenting a beautiful gray appearance Example 3. The pre-treatment process is the same as Example 1. Composition of bath solution: Zinc borate sulfate stannous sulfate citric acid Color development condition: Corresponding electrode current density color appearance carbon electrode . 0.8A / dm 2 presents a beautiful gray appearance 30g / l 50g / l 1.5g / l 20g / l 3g / l Temperature: 25 ° C Time: 9 minutes (" 尤 读 ifil ':: And '; ,,; dip f'f! &Quot;-, A-' ',;, Ben)) The case printed by the Ministry of Economic Affairs Central Standards Consumer Labor Cooperative and the case of GB14 08 859 "as shown in the table below The time required to display gray from the start of gray to black 3 »Ming ητυ 6 minutes and 12 minutes in this case because the color change per unit time is small, and it is easy to control the uniform color on the production island GB1408859 27 minutes and 3 minutes in the case due to the color per unit time The change is large. It is difficult to control a uniform color during production, and the color development time is too long. The aluminum oxide film is prone to loosening and falling off. The hooligan chooses to go to the top of the glass m in the 罔 Η family like Mou (CNS) Λ4 worry grid 丨 丨 X2 ^ Gonghua) Page 4

Claims (1)

Announcement 2 ^ 605 A8 B8 C8 D8 A special brake range is required. 1. An electrolytic coloring method for aluminum or aluminum alloy, including the following steps: It is first degreased: degreased in 30% nitric acid, washed with water; alkaline corrosion C Et ching): 10% sodium hydroxide eroded, washed with water; neutralization: neutralized with% nitric acid, washed with water; and anodized: 180 g / l sulfuric acid solution 18 DC voltage 17 V, anodized for 25 minutes, After washing with water, etc. before the above treatment; the composition of the bath solution is: 20 ~ 50 g / l 30 ~ 90 g / l 0. 5 ~ 4 5 g / l 10 ~ 50 g / l 1 ~ 15 g / l ( Please read the precautions first. Then fill this page) boric acid C Η 8 B 0 *) zinc sulfate C ZnS04 · 7Η20) stannous sulfate (SnS04) sulfuric acid (H2S04) stannous sulfate stabilizer and stannous sulfate The agent is selected from a group of organic acids including polybasic organic acids, such as tartaric acid; aromatic acids, such as phthalic acid; and sulfonic acids, such as methanesulfonic acid; organic acids that can reduce Sn + 4 to Sn + 2, and The operation method is: use alternating current, current density is 0.4 ~ 1.4 A / dm2 electrolysis and color development at normal temperature. 2. As in the method of item 1 of Shen Jing's patent scope, the composition of the bath solution is better. The formula is printed by the Employee Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economy. Boric acid: 30 ~ 50 g / L zinc sulfate: 40 ~ 70 g / Lithium stannous sulfate · 1_5 ~ 4.5g / L sulfuric acid: 15 ~ 35g / L 3. As in the method of claim i, the preferred current density is 0.6A / dm2 ~ 1.OA / dm2. 4. For example, the second or third method of the patent application scope, in which the color of the fifth page of the color of the paper color is Gu Guguan (CNS) H3. The depth of 295605 printed by the B Welfare Committee of the Central Standardization Bureau of the Ministry of Economic Affairs can be printed by 295605. The color development time depends on the time, usually between 6 and 15 minutes. 5. The method as claimed in item 丨 of the patent application, wherein the optimal concentration of stannous sulfate stabilizer is 3-8 g / l. . Sixth page The paper size is in accordance with Chinese National Standard (CN S) A4 (210 X 297 mm)