JPH0219493A - Various anodic treatments of aluminum member - Google Patents

Abstract

PURPOSE: To make it possible to continuously color an Al member in different colors, by subjecting the Al member to an anodic treatment to form an alumina film thereon, and destroying the deposited layer by machining after the electrolytic coloration, then subjecting the Al member to the anodic treatment and coloration.

CONSTITUTION: The Al member is subjected to surface polishing, degreasing and cleaning, and is then immersed into an electrolyte consisting of water, 180 to 200g/l sulfuric acid, and 5 to 10g/g alumina or aluminum sulfate. DC current of 12 to 15V is passed to the member to form the alumina film. The member is subjected to a coloration treatment in a deionization water bath contg. pigments or metal salt-contg. liquid after washing. The member is subjected to a sealing treatment after the washing. The member is then machined to destroy the layer deposited during the anodic treatment. The respective stages for the anodic treatment, coloring and sealing treatment are repeated again after the washing. As a result, the execution of the various anodic treatments is made possible without damaging the initially deposited film.

COPYRIGHT: (C)1990,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for carrying out various anodizing treatments on aluminum members which are treated by an electrolytic process or anodizing in an acidic medium.

[Conventional technology]

Traditionally, aluminum parts have been anodized once. This is because if anodization is applied to an already anodized surface, the second treatment will damage or partially destroy the first treatment.

The only way to color an aluminum member in two or more colors was to sequentially color the surface with lacquer (paint).

[Problem to be solved by the invention]

The present invention aims to provide a method for sequentially subjecting an aluminum component to various anodizing treatments without damaging the initial coating deposited.

[Means for Solving the Problems] The above object is achieved by the method of the present invention described below.

Aluminum parts are modified or polished to remove various types of surface irregularities to ensure uniform anodization. The entire surface is then cleaned in an acidic or alkaline medium or with a degreasing agent and then washed to remove any degreasing residues.

After completing the operations included in the above pretreatment, the next second step is started. This second step involves a sulfuric acid ratio of 150 to 20
10-15 V on aluminum parts and acidic medium in an electrolyte consisting of 0 g/l sulfuric acid + water and alumina or aluminum sulfate dissolved in an amount of about 5-10 g/l
chemical treatment by anodic treatment carried out through direct current. The resulting oxygen oxidizes the aluminum and coats the component with an oxide or alumina film. This film is amorphous at the center and crystalline at the edges. The electrolyte solute forms a film on the film while generating pores in the center of the alumina cells (the thickness of the film varies depending on the treatment time in the anodizing bath), making it possible to color the parts afterward. do.

Before coloring, the aluminum member is immersed in water to remove acid residue, and then placed in a coloring bath containing an organic or inorganic pigment in the case of chemical coloring, or a metal salt in the case of electrolytic coloring. These pigments or metal salts are impregnated into the anodized layer by immersion in water, then washed and sealed in a bath of boiling deionized water, and one molecule of water is added to each side of the anodized layer. The anodic treatment layer is transformed into alumina monohydrate by absorption.

To perform a second anodization on an aluminum member, the portion of the member to be anodized is processed to remove the layer formed in the first treatment and expose the aluminum. The reason why this removal is carried out by processing is that surface degreasing with an alkaline agent damages the layer formed by anodic oxidation, so it cannot be carried out.

Once the part of the part to be anodized has been cleaned, the chemical process is repeated under the same conditions as the previous treatment to form an anodized film on the part. It is also necessary to perform coloring.

In order to color the part in a further multi-color combination, the part to be newly colored can be machined, and the part can then be anodized and colored in correlation with the process steps carried out in the previous treatment. Process.

It is also possible to combine lacquer coloring with various anodizing treatments. In that case, it is first necessary to deposit a layer of lacquer or paint on the part, and then, after machining the part to be anodized, each of the aforementioned treatment steps once or twice
Perform anodization more than once.

As is clear from the above description, the preferable effects of the present invention are not limited to the details of the description in this specification,
Suitable changes may be made without changing the essential features of the invention.

Margin below

Claims (1)

[Claims] 1. A method of performing various anodizing treatments on an aluminum member, which comprises: polishing the surface of the aluminum member; degreasing the member with an acidic or alkaline medium or degreasing agent or removing a film; and then washing with water. a treatment step before anodization, with a mechanical pretreatment consisting of a cleaning step to remove the residues of the degreasing product; water and sulfuric acid in a ratio of 180 to 200 g/l;
The part is placed in an electrolytic solution consisting of alumina or aluminum sulfate in a ratio of 12 to 1 g/l.
An anodizing process in which a 5V direct current is passed to form an alumina film on the part, a cleaning process in which the part is immersed in water, and in the case of chemical coloring, a bath of deionized water containing organic or inorganic pigments. , a coloring step in which the component is placed in a bath containing metal salts in the case of electrolytic coloring, a cleaning step in which the component is immersed in water, and a step in which the component is placed in boiling deionized water to remove molecules of the anodized layer. A process of sealing by increasing the volume and absorbing water molecules and transforming into aluminum monohydrate, a machining process to destroy the layer deposited during the anodizing process, and a cleaning process by immersion in water. , anodizing under the same conditions as said anodizing to correspondingly color the anodized layer, and a sealing step carried out by immersion in boiling deionized water. How to do it. 2. The method according to claim 1, wherein the same aluminum member is continuously colored with different colors by repeating the steps. 3. The method according to claim 1, wherein the aluminum member is colored with paint before being machined before anodizing.