JPH03257177A - Production of aluminum crystal grain member - Google Patents

Abstract

PURPOSE:To form crystal grain patterns in relief and to improve ornamentality by subjecting an Al member to heat treatment to form coarser crystal grains, then subjecting the member to an etching treatment. CONSTITUTION:The Al member is subjected to the heat treatment to hold the member for about >=30 minutes at the temp. below the m.p. of Al to form the coarser crystal grains. The member is then subjected to the etching treatment by using an aq. soln. mixture, etc., composed of sulfuric acid and hydrochloric acid. The stains, etc., of the Al sheet surface are removed and the coarsened crystal grains are formed beautifully in relief. The patterns having surface steps of about 20mum in average are thus obtd. The crystal grain patterns having a variety of changes are obtd. if a plastic distortion is partially applied to the Al member before the above-mentioned heat treatment. The interference colors varying with each of the respective crystals are obtd. if the interference films are formed on the Al member after the etching treatment. This method is applicable to members of timepieces, accessories, stationery, interiors, etc.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a watch. Accessories-9 This invention relates to a method for manufacturing aluminum crystal grain members used for decorative members such as stationery, interior decoration, and building materials.

[Prior Art] Aluminum members are widely used for watch exteriors, building materials, etc. because they are lightweight, have good workability, and have good corrosion resistance.

[Scheme to solve the problem 1i] However, the raw surface of aluminum lacks decorative properties, and even if the color tone of the surface is changed by painting, alumite treatment, printing, chemical etching treatment, etc., it is still unsatisfactory as a decorative member. .

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for manufacturing an aluminum crystal grain member having a high degree of decorativeness.

[Means for Solving the Problems] In order to achieve the above object, the method for manufacturing an aluminum crystal grain member of the present invention includes a step of heat-treating an aluminum member to coarsen the crystal grains, and a step of coarsening the crystal grains by subjecting the aluminum member to a heat treatment. This process consists of a step of etching the aluminum member.

Furthermore, the manufacturing method may further include a step of partially applying plastic strain to the aluminum member before the heat treatment.

Furthermore, in the above manufacturing method, the aluminum member subjected to the etching treatment has a pattern ①b of the periodic table.

The method may further include a step of forming a transparent coating having a nitride, oxide, or carbide of at least one element in groups IVa, IVb, Va, and Via.

Furthermore, the above manufacturing method may further include a step of subjecting the etched aluminum member to alumite treatment.

In the above manufacturing method, it is effective to use a mixed aqueous solution of sulfuric acid and hydrochloric acid as the etching liquid.

[Function] In the present invention, in order to use the aluminum member for decoration, the crystal grains are coarsened to a size visible to the naked eye by heat treatment, and the decorativeness is improved by the pattern of the crystal grains. At this time, the crystal grain pattern is unclear when the aluminum member is still heat-treated, but the crystal grain pattern clearly stands out due to the etching treatment.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.

First, a first example will be described.

In this example, the aluminum member was A1080 (
purity 99.8% or more) or A1050 (purity 99.5% or more)
% or more) or Al100 (purity of 99.0% or more). Industrial pure aluminum plates are made by rolling, and the product has plastic strain in the rolling direction.

This aluminum plate is subjected to heat treatment. That is, at 500°C in the air or in a reducing gas or inert gas atmosphere.
The above temperature is maintained at a temperature below the melting point of aluminum (approximately 660° C.) for 30 minutes or more. Then, the aluminum recrystallizes, and the crystals become so coarse that they can be seen with the naked eye. However, in this state, the crystal structure cannot be clearly seen due to dirt on the surface of the aluminum plate.

Therefore, etching treatment is performed next. Water, 30% hydrochloric acid, 6
An etching solution containing 0% nitric acid mixed in a volume ratio of about 20:60:20 to 30:230:240 is prepared, and an aluminum plate is immersed in this etching solution for 5 to 10 minutes at room temperature. As a result, dirt and the like on the surface of the aluminum plate are removed, and the coarse crystal grains are neatly raised to the surface, resulting in a pattern with surface steps of an average of 20 μm.

Finally, the aluminum plate is washed with water to remove the etching solution, and a top coating or general colored coating is applied to obtain an aluminum plate having a crystal grain pattern.

Figures 1 to 3 are photographs showing aluminum crystal grain plates obtained by this method. Figure 1 shows an equiaxed grain structure with no directionality and a medium grain size, and Figure 2 shows the grain boundaries of the equiaxed grain.
Figure 3 shows the crystal grain shape of columnar crystals, which are large columnar structures with crystal orientation aligned in the rolling direction of the plate. Because these crystal grain shapes are etched,
A silvery white luster that does not originally exist in aluminum can be obtained. Furthermore, since each crystal grain has directionality, the crystal grains that reflect light differ depending on the viewing angle, and aluminum crystal grain members having these crystal grains have an extremely high aesthetic appearance.

Which of these crystal grain shapes can be obtained by recrystallization depends on the heat treatment conditions such as the purity of the aluminum plate, the material (processing rate), the plate thickness, and the heat treatment temperature.
By selecting these conditions, it is possible to obtain an aluminum plate having the desired grain shape.

Next, [Embodiment 2] will be described.

In this example, by taking advantage of the fact that the size of crystal grains can be changed depending on the degree of processing of the material, plastic working such as bending, drawing, pressing, and rolling is applied partially before heat treatment. It partially changes the crystal grain pattern.

As in the first embodiment, the aluminum members are commercially available industrial pure aluminum rolled plates A108Q and A1050.
Alternatively, Al100 is used.

First, as shown in the fourth figure, the rolled plate was bent in the rolling direction, and then heat treatment and etching treatment were performed under the same conditions as in the first example. In this case, in the aluminum crystal grain member 1, the crystal grains change on the outside 1a of the bent portion, and fine crystal grains are formed.

Note that inside the bent portion (not shown), the change in crystal grains is small. Note that when bending is performed in a direction perpendicular to the rolling direction, fine crystal grains are unlikely to be generated even if the bending angle is 90'' or more.

Next, the industrial pure aluminum rolled plate was drawn into a bell shape, and then subjected to heat treatment and etching treatment. In this case, as shown in FIG. 5, the clock bell-shaped decorative pendulum 2 made of aluminum crystal grains has fine crystals in the portions where the amount of plastic deformation is large due to the drawing process, that is, the drawing tip portion 2a and the drawing rear end portion 2b. Many grains are formed.

Next, as shown in FIG. 6, character shapes 3a and 3b of A and B were formed on an industrial pure aluminum rolled plate by press working to give plastic strain to those parts, and then heat treatment and etching were performed. In this crystal grain member 3, fine crystal grains are generated in the portions of the letter shapes 3a and 3b of letters A and B, and the letters A and B can be read due to the difference in crystal grain size from the base plate. For example, if a watch dial is manufactured using the pressed part as the numeral part of the watch dial, the numeral part will be displayed as fine crystal grains, and a dial made of a crystal grain member with high decorativeness will be obtained.

Next, a similar process was performed in which the step of partially imparting plastic strain was performed as roll rolling in which the rolling rate was continuously changed. As shown in FIG. 7, the grain shape of this aluminum crystal grain member 4 becomes smaller as the rolling rate increases, and the proportion of fine crystal grains increases, and finally, it consists only of fine crystal grains. Therefore, a continuously changing grain pattern is obtained.

Next, as shown in Fig. 8(a), the industrial pure aluminum rolled plate is bent at three locations along the rolling direction of the rolled plate and heat treated, and then as shown in Fig. 8(b). , the bending process was performed, and the etching process was performed. In this crystal grain plate 5, there is a large change in crystal grains on the outside of the bent part,
On the inside of the bent part, the degree of bending is low, so there is little change in the crystal grains, so as shown in Figures 8(c) and (d), a band-like striped pattern of fine crystal grains can be arbitrarily formed on one plane. It is possible to form Note that the step of restoring the bend can be easily performed because the material has been annealed by heat treatment.

Next, a third embodiment will be described.

In this example, an interference coating is further formed on an aluminum crystal grain member which has been etched to reveal a crystal grain pattern.

As interference coatings, I [Ib, IVa, IVb of the periodic table
.

A transparent film containing a nitride, oxide, or carbide of at least one element in groups Va and VIa, singly or in combination, is used. Sputtering and ionone coating are methods for forming the interference film.

Vacuum deposition or the like can be used. The film thickness is set to a thickness that allows the interference phenomenon to occur, and by controlling the film thickness, it is possible to adjust the colors that appear due to interference, such as red, orange, yellow, green, blue, blue-violet, and violet. The coating may be multilayered to strengthen it.

Since the crystal grain plate has a different crystal direction for each crystal grain, the surface roughness becomes non-uniform when etching is performed. Therefore, when an interference coating is formed on this, each crystal grain exhibits a different interference color. In other words, the surface roughness within the A crystal grain in Fig. 9(a) is gentle, and the surface roughness within the B crystal grain in Fig. 9(b) is rich in undulations. are different. Therefore, if a transparent film is formed on this and crystal grains A and B are viewed from the same direction, the direction of light reflected on the crystal grain surface and traveling toward the eye will be different, and therefore the inside of the transparent film will be different. The distance the light passes through is different, and different interference colors can be seen. Therefore, when looking at this aluminum member, various different interference colors appear in each crystal grain. Furthermore, changing the position of the eyes also changes the interference color, so
It is possible to obtain highly decorative interference colors.

In a specific example ε, for example, after heat treatment and etching treatment, washing with water to remove the etching solution, 0.5
Mirror treatment is performed using nickel plating with a thickness of μm, and zirconium oxide is coated with a thickness of 0.1 μm by sputtering or the like. As a result, the light is totally reflected on the nickel plated surface, improving the reflectance and making it possible to obtain a deeper interference color.

Next, a fourth embodiment will be described.

In this example, an aluminum crystal grain member that has been etched to reveal a crystal grain pattern is further subjected to an alumite treatment.

First, electrolysis is applied in a 15% sulfuric acid bath at 20 to 23° C. at DC 20 V and a current of 100 A/r&. Then, heat treatment and etching treatment are performed in the same manner as in the first embodiment, and the washed aluminum crystal grain member is immersed in this melt for 30 minutes to perform anodic oxidation. This produces an 8 μm thick oxide film.

Next, for example, 10 g/fl of dye is added to a solution containing 2.0 to 10 g/fl, a pH of 6.0 to 7.5, and a liquid temperature of 50 to 70°C.
Soak for a minute and stain.

Next, for example 5-5.8 g/l of nickel acetate.

Contains 1 g/l of cobalt acetate, 8-8.4 g/f2 of boric acid, and has a pH of 5-6. The surface is sealed by immersing it in a solution at a temperature of 70 to 90°C for 15 to 20 minutes.

As a result, an aluminum crystal grain member colored with the dye is obtained.

Since the aluminum crystal grain member after heat treatment is annealed, its wear resistance is reduced, but by performing alumite treatment, corrosion resistance, wear resistance, etc. are improved. In addition, aluminum crystal grain members have a silvery white color of the base material itself, but when dyed as described above, it becomes possible to obtain aluminum crystal grain members with various colors. .

Note that the above-mentioned mixed solution of hydrochloric acid and nitric acid is most suitable as the etching solution, but the etching solution is not limited thereto.

[Effects] In the present invention, an aluminum member is subjected to heat treatment to coarsen the crystal grains, and an etching treatment is performed to make the crystal grain pattern stand out, so that a highly decorative aluminum member can be obtained.

Furthermore, by applying plastic strain to a portion of the material before heat treatment, it is possible to obtain a varied crystal grain pattern in which the grain pattern is partially different.

Furthermore, by forming an interference coating on the etched aluminum crystal grain member, a different interference color can be obtained for each crystal grain, further increasing its value as a decorative member. Furthermore, since a transparent film is formed on the surface of the aluminum crystal grain member, the wear resistance and corrosion resistance of the aluminum crystal grain member are improved.

Furthermore, when alumite treatment is applied, the corrosion resistance and abrasion resistance of the aluminum crystal grain member are greatly improved, and when dyeing treatment is performed, it is possible to obtain aluminum crystal grain members of various colors.

[Brief explanation of drawings]

Figures 1 to 3 are photographs showing the crystal grain structure obtained by the present invention, and Figures 4 to 8 are explanatory diagrams showing cases in which plastic strain is partially applied to an aluminum plate before heat treatment. , FIG. 4 is a perspective view showing the case where bending is performed in the rolling direction,
Fig. 5 is a perspective view showing the case of drawing into a bell shape;
Figure 6(a) is a front view showing the case of pressing the character shape, Figure 6(b) is a bottom view of Figure 6(a), Figure 7(a)
7(b) is a bottom view of FIG. 7(a), FIG. 8(a) is a perspective view showing bending in the rolling direction, and FIG. b) is a perspective view showing the bent part returned to its original state after heat treatment, and FIG.
FIG. 8(d) is a perspective view showing the state of crystal grains on the front side of FIG. 8(a), and FIG. 9(a) is a perspective view showing the state of crystal grains on the back side. (b) is an explanatory diagram of interference effects between different crystal grains. 1 2. 3゜4.・Aluminum crystal grain parts. Applicant Seikosha Co., Ltd. Patent Attorney Kazuko Matsuda 4 Figure 5 Figure 5 ( ) 0 b (b) Rebellion No. 7 Fig. 8 Fig. 5°” ?+wt a+Ltk%'m Procedural amendment (method) Display of case 1990 Patent Application No. 53739 Title of invention Case of person who amends the manufacturing method of aluminum crystal grain member Relationship with Patent applicant: 2-6-21 Kyobashi, Chuo-ku, Tokyo (23it) Seikosha Co., Ltd. Representative Director Yu Yokoyama

Claims (5)

[Claims] (1) A method for manufacturing an aluminum crystal grain member, which comprises the steps of: heat treating the aluminum member to coarsen the crystal grains; and etching the aluminum member with coarse grains. (2) The method for manufacturing an aluminum grain member according to claim 1, further comprising the step of partially applying plastic strain to the aluminum member before the heat treatment. (3) In claim 1 or claim 2, the aluminum member subjected to the etching treatment is etched with I of the periodic table.
A method for manufacturing an aluminum crystal grain member, further comprising the step of forming a transparent coating having a nitride, oxide, or carbide of at least one element in groups IIb, IVa, IVb, Vb, and VIa. (4) The method for manufacturing an aluminum crystal grain member according to claim 1 or 2, further comprising the step of subjecting the etched aluminum member to an alumite treatment. (5) A method for manufacturing an aluminum crystal grain member according to any one of claims 1 to 4, characterized in that a mixed aqueous solution of sulfuric acid and hydrochloric acid is used as the etching solution.