JPH05320986A - Color developing intermetallic compound - Google Patents

Abstract

PURPOSE:To obtain a dense, uniform and thick coating film of a color developing intermetallic compd. with high electrolytic efficiency even in a bath having a single compsn. by carrying out electrolysis in an electrolytic soln. contg. an org. or inorg. acid when a specified alloy is anodically oxidized. CONSTITUTION:This intermetallic compd. consists of two or more among Ti, Nb, Al, Zr and Ta and one of them preferably accounts for 20-80 atomic% of the total amt. This intermetallic compd. may be blended with <20wt.% one or more among Mn, Cr, V, C, N, B, Si, W and Mo. For example, Ti55Al45 is anodically oxidized with a 10% aq. boric acid soln. as an electrolytic oxidizing soln. In this case, the developed color tone can highly be controlled by controlling bath voltage.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a chromogenic intermetallic compound. Such a colored intermetallic compound is extremely useful for applications such as ornaments, sports / leisure products, building materials, automobile materials, aircraft parts, and machine parts.

In this specification, "%" means
It shall mean "% by weight".

[0003]

2. Prior Art and its Problems Conventionally, Ti, Ta, N
It is known that pure metals such as b, Zr, and Hf and alloys thereof are colored by light interference when they are subjected to treatments such as anodic oxidation, thermal oxidation, and coating of a transparent thin film.

As the anodizing method, an aqueous solution, a non-aqueous solution,
There is an electrolytic method using a molten salt or the like, and generally an aqueous solution is often used.

With respect to Ti, for which this coloring technique is being actively used at present, when forming a film by anodic oxidation, there are the following problems, and in order to form a uniform oxide film, a high degree is required. Technology is required.

(1) A film can be formed relatively easily up to 100 V, but a spark discharge occurs at 100 V or more.
It is difficult for the voltage to rise.

(2) The efficiency of film formation is poor.

(3) To produce thick films, not single composition baths. A multi-component electrolytic bath (for example, phosphoric acid-sulfuric acid-hydrogen peroxide solution) is required.

(4) Since the film obtained in (3) above is porous, it requires post-treatment.

(5) It is difficult to control the film thickness.

Further, regarding the intermetallic compound itself, there is no report regarding color development.

[0012]

Therefore, the present invention mainly aims to find a new technique capable of producing a dense and uniform color-forming film on a metal surface with high electrolysis efficiency even in a single composition bath. To aim.

[0013]

The present inventor has conducted research in view of the current state of the art as described above, and as a result, Ti, Nb, A
When an intermetallic compound consisting of a combination of two or more specific metals selected from the group consisting of 1, Zr and Ta is subjected to anodic oxidation, the anodic oxidation can be carried out very easily, Being dense even in an electrolytic bath, capable of forming a thick color-forming barrier type film with high electrolysis efficiency,
It has been found that the color tone of color development can be controlled with high precision. Such findings are based on the fact that the above intermetallic compounds are Ti, T
Considering that the crystal structure is completely different from that of pure metals such as a, Nb, Zr, and Hf, it was completely unexpected.

The present invention has been completed on the basis of such novel findings, and provides the following intermetallic compounds: A colored intermetallic compound obtained by electrolysis in an electrolytic solution containing an organic acid or an inorganic acid.

2. A color-forming intermetallic compound obtained by performing an oxidative heat treatment at a temperature of 400 ° C. or higher.

3. The constituent metal elements are Ti, Nb, Al, Z
Item 3. The chromogenic intermetallic compound according to Item 1 or 2, which is composed of at least two kinds of r and Ta, and one kind of which accounts for 20 to 80 atomic% of the whole.

The intermetallic compound which is the object of the present invention is T
It is composed of at least two kinds of i, Nb, Al, Zr and Ta. As such intermetallic compounds, more specifically, Ti-Al-based, Nb-Ti-based, Nb-A
Examples include l-type, Ta-Al, and Zr-Al. In such intermetallic compounds, Ti, Nb, Al, Zr
The amount of one of Ta and Ta is preferably in the range of 20 to 80 atomic%. In addition, these intermetallic compounds include
Within the range of not exceeding 20% of its weight, Mn, Cr, V,
You may mix | blend at least 1 sort (s) of C, N, B, Si, W, and Mo. The addition of such an additional element as the third component originally has the effect of improving the mechanical strength of the intermetallic compound, but may hardly adversely affect the excellent color development of the intermetallic compound. found.

The electrolytic solution may be an inorganic acid aqueous solution or non-aqueous solution, an organic acid aqueous solution or non-aqueous solution, or a molten salt. As the inorganic acid, boric acid, phosphoric acid, sulfuric acid,
Chromic acid is exemplified, and one or more of these are used. Examples of the organic acid include formic acid, acetic acid, oxalic acid, sulfonic acid and the like, and one or more of these are used. Examples of the non-aqueous solvent include methanol, ethanol, ethylene glycol, ethylene glycol monoethyl ether and the like. Examples of the molten salt as the electrolytic solution include sodium oxalate. The electrolysis conditions are not particularly limited, but usually a current density of 1 to 1000 mA / cm ² (DC voltage) and a predetermined voltage of 2
The voltage is increased until it becomes 0 to 500 V, and then constant voltage electrolysis is performed.

The intermetallic compound which has been subjected to the above-mentioned anodic oxidation treatment is further heated to 300 ° C. or higher, more preferably 400 ° C.
The above heat treatment improves the corrosion resistance of the film. Further, instead of the above anodizing treatment, 400 ° C. or higher,
More preferably, the chromogenic intermetallic compound according to the present invention can be obtained by performing the oxidative heat treatment at 600 ° C. or higher. That is, by performing heat treatment at a temperature of 600 to 800 ° C. in the atmosphere, vivid interference colors of blue, blue green, and yellow green can be easily obtained. Even at a low temperature of 400 to 600 ° C, it takes a long time (100 hours or more) until an oxide film having a thickness exhibiting an interference color grows, but basically the same result as the heat treatment at 600 to 800 ° C is obtained. can get.

[0020]

According to the present invention, the following remarkable effects are exhibited.

The anodic oxidation treatment can be carried out very easily.

Dense, using an electrolytic bath of single composition,
A thick color forming barrier type film can be formed with high electrolysis efficiency.

The color tone of the coating can be controlled highly and precisely.

[0024]

EXAMPLES Examples will be shown below to further clarify the features of the present invention.

Example 1 Using a 10% boric acid aqueous solution as an electrolytic oxidizing solution, Ti ₅₅ Al ₄₅
Was subjected to anodic electrolytic oxidation treatment. The current density when the voltage increased was 10 mA / cm ² .

FIG. 1 is a Hunter diagram showing the relationship between a value, b value and hue.

FIG. 2 is a Hunter diagram showing the relationship between the anodic oxidation voltage (numerical values on the curve in the figure) and the hue of the interference thin film produced in this example.

For comparison, FIG. 3 shows the relationship between the anodic oxidation voltage (numerical values on the curve in the figure) and the hue of the interference thin film produced when metal Ti is similarly subjected to an anodic electrolytic oxidation treatment by means of a Hunter diagram. Show.

As is clear from the results shown in FIG. 3, in the case of Ti, the bath voltage did not rise above 50 V and the change in color tone was poor.

On the other hand, in the case of Ti ₅₅ Al ₄₅ , the color tone was clearly changed, and it was possible to highly control the color tone by controlling the bath voltage.

Unlike the case of titanium metal, the film formed during the anodizing treatment of Ti ₅₅ Al ₄₅ has a low electron conductivity and a high ionic conductivity. The migration of ions was easy and the oxide film was formed efficiently. More specifically, the electrolysis efficiency in the case of forming a pressure resistant film of 200 V is 9 for Ti ₅₅ Al _45.
While it was 7%, it was only 25% for metallic Ti.

In particular, the magnitude of the current (leakage current) when anodizing at a constant voltage is several tenths of that of titanium metal,
The barrier property of the formed film was very excellent.

Example 2 Various intermetallic compounds having different compositions were anodized to obtain 8
An oxide film having a withstand voltage of 0 to 100 V was formed and the color tone was measured.

The results are shown in Table 1 below.

[0035] 1 materials anodizing voltage table _{(V) L a b Ti 50} Al 50 100 24.41 2.21 -23.41 Nb 37 Ti 63 100 33.31 -2.19 1.92 Nb 66 Al 34 100 35.22 -3.15 4.68 Nb ₃₇ even Ti ₆₃ 80 31.96 -9.96 -0.66 any intermetallic compounds, interference thin film is formed, color (L, a, b) changed greatly and showed a vivid interference color.

Example 3 Ti ₅₅ Al ₄₅ was anodized at 100 V in an electrolyte containing 0.5% phosphoric acid or 10% boric acid, and then subjected to a pressure cooker test (121 ° C., 2 atmospheres, 6 hours). To obtain blue-green samples (a) and (b).

Further, Ti ₅₅ Al ₄₅ was anodized in an electrolytic solution containing 10% boric acid at 100 V, and then 2 hours at 400 ° C.
The sample was heat-treated for 0 minutes and then subjected to a pressure cooker test (121 ° C., 2 atmospheres, 6 hours) to obtain a sample (c).

Before and after the test (60 hours later, 1
Changes in color tone after 20 hours and 200 hours) are shown in Table 2.

[0039] Table 2 specimen L a b test before (a) 41.67 -12.39 -29.12 (b ) 43.80 -16.79 -20.12 (c) 38.64 -14.60 -29.98 60 hours later (a) 41.99 -12.52 -28.78 (b) 43.98 -17.10 -20.78 (c) 37.63 -14.23 -30.92 120 After hours (a) 43.74-9.93-11.82 (b) 43.71-16.11-19.99 (c) 37.01-12.62-28.32 After 200 hours (a) 51.35-6.82 4.93 (b) 43.71 -15.23 -20.49 (c) 38.52 -13.61 -31.05 As is apparent from the results shown in Table 2, the pressure is shown. Before and after the cooker test Reduction was not observed, the product according to the present invention exhibited excellent water wettable. Especially, the sample (c) showed extremely excellent hydration resistance.

Example 4 Ti ₅₅ Al ₄₅ was anodized in an electrolytic solution containing 0.1% phosphoric acid at 100 V to obtain a sample (d).

Further, Ti ₅₅ Al ₄₅ was anodized in an electrolytic solution containing 0.1% phosphoric acid at 100 V and then 60 in air.
It heat-processed at 0 degreeC and the sample (e) was obtained.

Further, untreated Ti ₅₅ Al ₄₅ was used as a sample (f).

Each of these samples was treated with 2% HF + 3% HNO ₃
The sample was dipped in the mixed aqueous solution and the time from dipping to gas generation was measured to determine the corrosion resistance.

The results are shown in Table 3.

Table 3 Sample surface Surface time until generation of processing gas (d) Anodizing 1 minute 08 seconds (e) Anodizing + heat treatment 1 minute 45 seconds (f) No treatment 3 seconds From the results shown in Table 3, The color-forming intermetallic compound according to the present invention has improved corrosion resistance because the induction time until the film is dissolved and the substrate is eroded is long.

Example 5 Table 4 shows the change in color tone when Ti ₅₅ Al ₄₅ was heat-treated in the air at each temperature from 400 to 750 ° C. for 30 minutes.

[0047] Table 4 heat treatment temperature (℃) L a b untreated 52.61 -0.45 2.74 400 41.49 1.11 7.31 450 45.40 1.76 7.49 500 40.51 1 .50 5.31 550 38.44 0.94-1.68 600 40.89-1.14-10.91 650 42.22-4.36-14.32 700 49.43-5.61-10 .86 750 40.02 -2.86-0.05 The color tone changed from the time when the heating temperature was around 600 ° C, and a blue color interference thin film was obtained. The color tone was almost equivalent to that of the anodic oxidation voltage of 80 V in FIG. Further, even at 500 ° C., by performing heating for a long time, an interference thin film similar to that at heating at around 600 ° C. was obtained.

[Brief description of drawings]

FIG. 1 is a Hunter diagram showing the relationship between a value, b value and hue.

2 is a Hunter diagram showing the relationship between the anodic oxidation voltage (numerical values on the curve in the figure) and the hue of the interference thin film produced for the product obtained in Example 1. FIG.

FIG. 3 is a Hunter diagram showing the relationship between the anodizing voltage (numerical values on the curve in the figure) and the hue of the interference thin film produced when metal Ti is subjected to anodizing treatment in the same manner as in Example 1. is there.

Claims (3)

[Claims] 1. A colored intermetallic compound obtained by electrolysis in an electrolytic solution containing an organic acid or an inorganic acid. 2. A color-forming intermetallic compound obtained by performing an oxidative heat treatment at a temperature of 400 ° C. or higher. 3. The coloring metal according to claim 1, wherein the constituent metal element comprises at least two kinds of Ti, Nb, Al, Zr and Ta, and one of them constitutes 20 to 80 atomic% of the whole. Inter-compound.