JPH03173734A - Aluminum alloy for self-coloring - Google Patents

Abstract

PURPOSE:To manufacture the Al alloy for self-coloring obtaining a uniform and stable color tone free from the generation of color irregularity by anodic oxidation treatment by incorporating specified ratios of Fe, Sc, Y and lanthanoide series elements into Al. CONSTITUTION:An Al alloy for self coloring contg., by weight, 0.2 to 3.0% Fe, furthermore contg. total 0.003 to 0.5% of one or >=2 kinds among Sc, Y and lanthanoide series elements (from No.57 element La to No.71 element Lu) and the balance Al with inevitable impurities is prepd. In this way, an Al alloy showing a uniform and stable color tone when a color developing film for ornament (preferably having about 5 to 30mu film thickness) is formed on the surface by anodic oxidation treatment can be obtd., and its product value can be increased.

Description

Detailed Description of the Invention: Industrial Field of Application This invention relates to naturally colored aluminum alloys, in particular those produced by anodizing to produce a colored film on the surface for decoration or base treatment, and used as decorative materials, building materials, etc. A to be done
This invention relates to a Q-Fe-based aluminum alloy for natural color development.

2. Description of the Related Art In order to obtain a colored aluminum material having a dark gray to black tone, a method of naturally developing an AQ-Fe alloy is known. This natural coloring method is a method of obtaining a desired color tone depending on the intermetallic compound such as Afi6Fe produced in the manufacturing process of the alloy by subjecting the AQ-Fe alloy to anodizing treatment.

Problems to be Solved by the Invention However, with conventional AQ-Fe alloys for natural coloring, due to subtle differences in manufacturing conditions, particularly differences in cooling rate during casting, the crystallization form of intermetallic compounds differs. A macrostructure called a main structure is formed, which causes color unevenness defects in the color tone after anodizing treatment, resulting in a significant deterioration of product quality.

The present invention was made to eliminate such drawbacks, and the object of the present invention is to provide an AQ-Fe-based aluminum alloy for natural color development, which can obtain a uniform and stable color tone without color unevenness after anodizing treatment.

Means for Solving the Problems In order to achieve the above object, the inventor conducted various experiments and research and found that a uniform and stable color tone could be obtained by containing a certain amount of rare earth elements together with Fe. This is the heading that completed this invention.

That is, the above objective is F e : 0. 2-3.0w1%
An aluminum alloy for natural coloring, characterized in that it further contains 5cSY and one or more of the lanthanum series elements in a total amount of 0.003 to 0.5 wt%, with the remainder consisting of aluminum and inevitable impurities. achieved by

In the aluminum alloy according to the present invention, Fe is an essential element in order to obtain a gray to black color tone. However, if the content is less than 0.2wt%, a deep color tone cannot be obtained, and on the other hand, if it exceeds 3°0w1%, the quality of the anodic oxide film formed on the alloy surface will deteriorate and the corrosion resistance will deteriorate, making it difficult to put into practical use. This may lead to a risk of not being able to withstand the situation. A particularly preferable Fe content range is 1.0 to 2. It is 0w1%.

5cSY as a rare earth element and a lanthanum series element both play a role in producing a uniform color tone in the film after anodizing treatment. All of these are equivalent in terms of such effects, and it is sufficient to contain one or more of them.

Here, the lanthanum series elements are from the 57th element La to the 71st
La5Ce, Pr, NdSPm, Sm up to the number element Lu
5EuSGd, Tb, Dy, Ho5E", Tm, Yb5
A general term for the 15 elements of Lu.

Therefore, it is necessary that one or more of these 15 elements plus 5cSY, which is a total of 17 elements, be contained. These elements total 0.003~0.5wt
% range, a stabilized AQ-Fe-based intermetallic compound containing these elements will crystallize during casting, etc., thereby suppressing the generation of a macrostructure called a fir tree structure, and eventually It is thought that a uniform and stable color tone without color unevenness can be obtained when anodized. However, if the total content is less than 0.003 vt%, there is no effect of realizing a uniform color tone, and color unevenness occurs in the color tone after anodizing treatment. On the other hand, if the total content exceeds 0.5 νt%, giant intermetallic compounds (primary crystals) will be generated, causing internal and surface defects in the processed material, as well as reducing corrosion resistance and increasing manufacturing costs. Cause. A particularly preferable content is 0.005 to 0.1 vt% in total.

The type of anodic oxidation treatment applied to the aluminum alloy is not particularly limited (although any treatment that can be used for the natural coloring method of AQ-Fe alloys may be adopted as appropriate, but the sulfuric acid method is preferable.

Processing conditions such as the concentration of the processing bath, bath temperature, current density, etc. are not particularly limited, and processing conditions commonly employed in natural coloring methods can be appropriately adopted. The thickness of the oxide film is generally desirably about 5 to 30 μm. This is because if the thickness is less than 5 μm, the coloring may be insufficient and the corrosion resistance may be poor. Further, a film thickness of 30 μm is sufficient in terms of coloring and corrosion resistance, and if the film is thicker than this, the effect will be saturated, and rather energy will be wasted, resulting in a greater economic disadvantage.

Effects of the Invention The aluminum alloy for natural color development according to the present invention has Fe: 0. Contains 2-3.0w1%,
Furthermore, since it contains a total of 0.003 to 0.5 wt% of one or more of Sc, Y, and lanthanum series elements, and the balance consists of aluminum and unavoidable impurities, by using this alloy, As is clear from the examples, the color unevenness after anodizing treatment can be eliminated,
A uniform and stable color tone can be achieved, which in turn can increase product value.

Example Next, examples of this invention will be shown.

After casting aluminum alloy slabs with various compositions shown in Table 1 below by semi-continuous casting according to conventional methods, each slab was sequentially subjected to hot rolling, cold rolling, annealing, and final rolling according to conventional methods. Various AΩ-Fe alloy materials having a length of 10,100 m, a width of 100,100 m, and a thickness of 2.0 m were obtained.

[Margins below] Next, each material was subjected to sulfuric acid anodization treatment in a 15% sulfuric acid bath at a bath temperature of 20°C and a current density of 100 A/m. A sulfuric acid film was formed.

When we visually observed the color tone and presence or absence of color unevenness on the surface of each alloy material after treatment, we found that the color tone was dark gray to black in all cases, but almost no color unevenness was observed in the products implemented according to the present invention. In contrast, the conventional product clearly had color unevenness.

Therefore, it was confirmed that according to the aluminum alloy for natural coloring according to the present invention, a uniform and stable color tone without color unevenness could be obtained after anodizing treatment.

that's all

Claims (1)

[Claims] Contains Fe: 0.2 to 3.0 wt%, and further contains Sc, Y
, a total of 0 of one or more of each element in the lanthanum series
．． An aluminum alloy for natural coloring, characterized in that it contains 0.003 to 0.5 wt%, and the remainder consists of aluminum and unavoidable impurities.