JP2002285360A - Chemical polishing solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a chemical polishing solution for aluminum or an alloy thereof which smoothens the surface of aluminum or the alloy thereof by chemical polishing, and can impart sufficient luster to the surface subjected to the chemical polishing without incorporating nitric acid therein. SOLUTION: Inorganic acid other than nitric acid and a tungsten compound are blended to prepare the chemical polishing solution. As the inorganic acid, sulfuric acid and phosphoric acid are preferably used, and also, copper ions, iron ions, or the like, are preferably blended therein.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical polishing liquid for chemically polishing aluminum or an alloy thereof, and more particularly to a method for smoothing the surface of aluminum and its alloy without adding nitric acid. The present invention relates to a chemical polishing liquid capable of imparting a high gloss.

[0002]

2. Description of the Related Art Conventionally, aluminum and its alloys (hereinafter, referred to as aluminum)
As a chemical polishing liquid for smoothing the surface of the material and sometimes giving it a gloss, a mixture of phosphoric acid and nitric acid has been generally used. . Although the mechanism of chemical polishing of aluminum or the like by such a chemical polishing liquid is not precisely elucidated, it is considered that chemical polishing proceeds by the oxidizing action of aluminum by nitric acid and the dissolving action of aluminum by phosphoric acid. ing.

[0003]

However, when such a chemical polishing solution containing nitric acid is used, nitric acid is decomposed in the course of chemical polishing to generate toxic nitrogen oxides. In addition, since the concentration of nitric acid in the solution decreases due to such decomposition of nitric acid, the nitric acid concentration must be maintained by replenishing nitric acid in the chemical polishing solution. In addition, when chemical polishing is performed in a state where a metal fastener of aluminum is attached to a cloth, a pigment used for dyeing the cloth may be discolored by nitric acid in some cases.

For this reason, development of a chemical polishing solution containing no nitric acid has been promoted. However, with such a chemical polishing solution containing no nitric acid, the surface of aluminum or the like is sufficiently polished or the polishing surface has a sufficient gloss. Cannot be given.

The present invention has been made in view of the above-mentioned points, and has been made to smoothen the surface of aluminum or its alloy by chemical polishing without containing nitric acid, and to impart sufficient gloss to the surface subjected to chemical polishing. It is an object of the present invention to provide a chemical polishing liquid for aluminum or an alloy thereof, which can impart the following.

[0006]

The chemical polishing liquid according to claim 1 of the present invention is a chemical polishing liquid for aluminum or an alloy thereof, which is composed of an inorganic acid other than nitric acid and a tungsten compound. It is characterized by the following.

A second aspect of the present invention is characterized in that, in the first aspect, phosphoric acid and sulfuric acid are blended as the inorganic acid.

[0008] The invention of claim 3 is characterized in that, in claim 1 or 2, it contains copper ions.

A fourth aspect of the present invention is characterized in that, in any one of the first to third aspects, the composition contains iron ions.

A fifth aspect of the present invention is characterized in that, in any one of the first to fourth aspects, at least one of a calcium ion and a molybdenum ion is contained.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the tungsten compound is added in an amount of 0.1 to 100 parts by mass of the total amount of the chemical polishing liquid in terms of metal tungsten.
It is characterized in that it is blended in an amount of from 0.01 to 5.0 parts by mass.

According to a seventh aspect of the present invention, in any one of the third to sixth aspects, 0.001 to 0.1 parts by mass of copper ion is blended with respect to 100 parts by mass of the total amount of the chemical polishing liquid. It is a feature.

The invention of claim 8 is the invention according to any one of claims 4 to 7, wherein 0.01 to 0.50 parts by mass of iron ion is blended with respect to 100 parts by mass of the total amount of the chemical polishing liquid. It is a feature.

According to a ninth aspect of the present invention, in any one of the second to eighth aspects, 70 to 30 parts by mass of phosphoric acid and 30 to 70 parts by mass of sulfuric acid are added to 100 parts by mass of the total amount of the chemical polishing liquid. It is characterized by comprising.

[0015] The invention of claim 10 is the invention of claims 1 to 9
Any one of the above, wherein sodium metaphosphate is blended.

[0016]

Embodiments of the present invention will be described below.

In the present invention, a chemical polishing liquid is prepared by blending an inorganic acid, and no nitric acid is blended at this time. Further, in the present invention, a tungsten compound is blended in the chemical polishing liquid.

As the tungsten compound, for example, phosphotungstic acid, sodium tungstate, or the like can be compounded, and the compounding amount is 0.01 to 5.0 in terms of metal tungsten, based on 100 parts by mass of the total amount of the chemical polishing liquid.
It is preferably 0 parts by mass. If the amount of the tungsten compound is less than this range, it is difficult to impart sufficient gloss to the surface of aluminum or the like, while if the amount of the tungsten compound exceeds this range, a part of the tungsten compound may be contained in the chemical polishing liquid. May precipitate without dissolving.

Further, in order to impart further gloss to aluminum and its alloys, it is preferable to mix copper ions in the chemical polishing liquid. At this time, for example, copper sulfate can be compounded in the chemical polishing liquid by mixing copper sulfate in the chemical polishing liquid. It is preferable that the compounding amount of the copper ion is 0.001 to 0.1 parts by mass in terms of metallic copper based on 100 parts by mass of the total amount of the chemical polishing liquid. If the amount of the copper ion is less than this range, the effect of improving the gloss of the surface of aluminum or the like cannot be sufficiently obtained.
If the compounding amount exceeds this range, black precipitation may occur on the surface of aluminum or the like after the chemical polishing treatment.

In order to impart uniform gloss to the surface of aluminum or the like, it is preferable to mix iron ions in the chemical polishing liquid. In this case, for example, by mixing ferrous sulfate, ferric sulfate, iron phosphate, and the like in the chemical polishing liquid, iron ions can be mixed in the chemical polishing liquid.
At this time, when a trivalent iron ion is used as the iron ion, the oxidizing power is improved, and the uniformity of gloss can be further improved. The compounding amount of iron ion is 10
With respect to 0 parts by mass, it is preferable to be 0.01 to 0.50 parts by mass in terms of metallic iron, and when the compounding amount of iron ions is less than this range or when the compounding amount exceeds this range. There is a possibility that the surface gloss of aluminum or the like becomes uneven.

Further, various other metal ions can be blended in the chemical polishing liquid. For example, when calcium ions or molybdenum ions are contained, the surface of aluminum or the like after chemical polishing can be further smoothed or glossed. In addition, various metal ions such as chromium ion, nickel ion, sodium ion and the like can also be blended. For example, sodium ion is inevitably blended when sodium tungstate is blended as a tungsten compound. You.

As the inorganic acid to be added to the chemical polishing liquid, it is particularly preferable to use phosphoric acid and sulfuric acid together.
In this case, the chemical polishing liquid has a good polishing power, and the polishing power is high even when the polishing is performed continuously.When each of the above-mentioned various components other than the inorganic acid is added, the chemical polishing liquid is used. It can be dissolved well. Regarding the compounding amounts of phosphoric acid and sulfuric acid, for smoothing aluminum and the like and for imparting gloss, 70 to 30 parts by mass of phosphoric acid and 30 to 70 parts by mass of sulfuric acid with respect to 100 parts by mass of the total chemical polishing liquid. It is preferable to mix them. At this time, phosphoric acid and sulfuric acid are
In such a range of the compounding ratio, a desired compounding amount of the above-described tungsten compound or metal ion can be ensured, and the compound can be compounded in an appropriate compounding amount.
Thus, in order to ensure the compounding amount of the tungsten compound and the metal ion, the total amount of the phosphoric acid and the sulfuric acid is in the range of 60 to 95 parts by mass with respect to 100 parts by mass of the chemical polishing liquid. Is preferable. Here, when the compounding amount of the phosphoric acid exceeds the above range or the compounding amount of the sulfuric acid is less than the above range, the durability of the polishing force is insufficient, or the polishing force is insufficient. There is a risk that smoothing or glossing may not be possible, and conversely, if the compounding amount of phosphoric acid is less than the above range or if the compounding amount of sulfuric acid exceeds the above range, the solubility of the tungsten compound etc. There is a possibility that smoothing or glossing may not be possible due to a reduction in precipitation and an excessive polishing force resulting in a roughened polished surface.

Further, a metaphosphate such as sodium metaphosphate may be added to the chemical polishing liquid. In this case, the surface of aluminum or the like after the chemical polishing is further smoothed and gloss imparted. Can be. Although the reason is not clear, it is considered that the chemical polishing of aluminum or the like by the chemical polishing liquid involves the formation of a relatively thick surface layer on the surface of aluminum or the like and the distribution of metal ions on the surface of aluminum or the like. Because, the formation of the surface layer is promoted by the metaphosphate, and the metal ions are distributed on the surface of aluminum or the like by chelate bonding of the metal ions to metaphosphoric acid,
It is considered that polishing of the surface of aluminum or the like is promoted. In addition, by chelating the metal ions in this manner, the solubility when the metal ions are mixed in the chemical polishing liquid can be improved, and the chemical polishing liquid can be stabilized.
As the metaphosphate, especially when using a thing having an amorphous three-dimensional network structure called ultraphosphate, it is possible to achieve further smoothing and gloss imparting,
This is considered because the formation of a surface layer on the surface of aluminum or the like is further promoted by the ultraphosphate. The metaphosphate (ultraphosphate) preferably has an average molecular weight in the range of 5,000 to 10,000.

In preparing the chemical polishing liquid according to the present invention, a predetermined amount of each of the above-mentioned components is blended and agitated and mixed, whereby a chemical polishing liquid can be obtained.

Using the thus prepared chemical polishing liquid,
In a state where the chemical polishing liquid is heated, the surface of aluminum or the like is chemically polished by pre-mechanical polishing or the like and immersing preheated aluminum or the like in the chemical polishing liquid as necessary. Can be. The liquid temperature of the chemical polishing liquid at this time is preferably 60 to 150 ° C., and if the liquid temperature of the chemical polishing liquid is lower than 60 ° C., it becomes difficult to sufficiently impart gloss. If it exceeds, roughening tends to occur on the polished surface. Especially, the liquid temperature is 80 ~ 1
When the temperature is set to 20 ° C., it is possible to have good polishing properties and to impart sufficient gloss. The immersion time in the chemical polishing liquid depends on the composition and dimensions of the aluminum alloy, etc., whether or not there is preheating,
Although it is appropriately set according to the liquid temperature or the like, it is preferably selected from the range of 20 to 240 seconds.
Further, the immersion time in a chemical polishing liquid such as aluminum is set to 20.
When the aluminum or the like is immersed in a chemical polishing solution a plurality of times as appropriate as well as in a short time of about two seconds, particularly excellent gloss is obtained on the polished surface.

As described above, when chemical polishing of aluminum or the like is performed with the chemical polishing liquid of the present invention, a material having excellent polishing power, capable of sufficiently smoothing the surface and providing excellent gloss can be provided. In addition, since nitric acid is not included in the solution, no harmful nitrogen oxides are generated by the decomposition of nitric acid during the chemical polishing process, and nitric acid is added to maintain the nitric acid concentration. There is no need to add them inside. In addition, since nitric acid is not used, the pigment does not discolor, and, for example, even when the fastener is attached to the cloth and chemically polished, the dyed cloth does not discolor. It is.

[0027]

The present invention will be described below in detail with reference to examples.

Examples 1 to 23 and Comparative Examples As raw materials, aqueous sulfuric acid, aqueous phosphoric acid, aqueous iron phosphate, copper sulfate, phosphotungstic acid, calcium sulfate, ammonium molybdate, sodium metaphosphate (ultraphosphate Sodium; average molecular weight 7000) and water were used, and predetermined amounts of raw materials were mixed and mixed to prepare a chemical polishing liquid having a composition as shown in Tables 1 and 2 below. The compounding amounts in the table are based on 100 parts by mass of the chemical polishing liquid. Here, copper sulfate and phosphotungstic acid were dissolved in water to form an aqueous solution, and then mixed with other raw materials.

(Abrasiveness evaluation test) In the chemical polishing liquids of the respective examples and comparative examples, A1070 specified by JIS standards,
A test piece made of each of the aluminum alloy materials A1050 and A6063 was immersed and subjected to chemical polishing. At this time, a test piece having a size of 50 mm × 70 mm × 1 mm was used, and this test piece was immersed in 500 g of a chemical polishing liquid maintained at 100 ° C. for 60 seconds.

The test pieces after the chemical polishing were evaluated as follows.

Evaluation of polishing power The weight of the test piece after chemical polishing was compared with the weight before the test, and the evaluation was made according to the following evaluation criteria. ：: Weight reduction rate of 2% or more ○: Weight reduction rate of 1% to less than 2% △: Weight reduction rate of 0.1% to less than 1% ×: Weight reduction rate of less than 0.1% ・ Gloss evaluation Test after chemical polishing The surface of the piece was visually observed and evaluated according to the following evaluation criteria. ：: Excellent gloss ○: Good gloss △: Slightly weak ×: Insufficient gloss ・ Evaluation of gloss unevenness The number of spots generated on the surface of the test piece after chemical polishing was counted, and The evaluation was performed according to the following evaluation criteria. ◎: 0 spots ○: 1 to 5 spots Δ: 6 to 19 spots ×: 20 or more spots The above results are shown in Tables 1 and 2.

[0032]

[Table 1]

[0033]

[Table 2]

As is clear from the results, Examples 1 to 23 containing a tungsten compound in addition to sulfuric acid and phosphoric acid have higher polishing properties than the comparative example containing no tungsten compound, and The test piece had an improved gloss.

In Examples 1 to 15 in which the compounding amounts of phosphoric acid and sulfuric acid were fixed and the compounding amounts of iron ion, copper ion and tungsten compound were varied, in Example 12 in which the compounding amount of the tungsten compound was large, Part of the tungsten compound remained without being dissolved in the polishing liquid, and in Example 11, where the blending amount was small, the gloss was slightly lowered. Example 10 with a large amount of iron ions,
Conversely, in Example 9 in which the amount of iron ions was small, slight unevenness was generated in gloss. In Example 13 in which the amount of copper ions was small, the gloss was slightly reduced. In Example 14 in which the amount of copper ions was large, excellent gloss was obtained, but a slight black deposit was observed on the surface of the test piece. Occurred.

Further, in Examples 15 to 19 in which the amounts of sulfuric acid and phosphoric acid were varied, in Example 19 in which the amount of sulfuric acid was large and the amount of phosphoric acid was small, the polishing power was high, but the gloss was slightly high. In addition, the tungsten compound was partially insoluble and remained without being dissolved. On the other hand, in Example 18 in which the amount of sulfuric acid was large and the amount of phosphoric acid was large, the polishing power was slightly inferior and the gloss was slightly lowered.

Further, in Examples 20 to 23 in which molybdenum ion, calcium ion or sodium metaphosphate was blended, the polishing properties and gloss were further improved, and the gloss was not uneven. And Example 23 in which sodium metaphosphate was blended,
A remarkable effect was observed in the improvement of the polishing properties and gloss and the suppression of uneven gloss.

(Continuous workability evaluation test) The chemical polishing liquid of Example 15 and a chemical polishing liquid in which aluminum was dissolved at various concentrations in this chemical polishing liquid were prepared.
A test piece made of each of the aluminum alloy materials of A1070 and A6063 specified by the IS standard was immersed and subjected to chemical polishing. At this time, the test piece having a size of 50 mm × 70 mm × 1 mm for A1070 (9.
3 to 9.4 g), and 50 mm × 7 for A6063.
One having a size of 0 mm x 3 mm (27.0 to 27.
2 g) was used, and the test piece was immersed in 500 g of a chemical polishing solution maintained at 100 ° C. for 60 seconds.

The weight of each test piece after the treatment was measured to derive a weight loss rate, a weight loss per area, and a polished thickness, and the glossiness was evaluated according to the same evaluation criteria as described above. Table 3 shows the results.

[0040]

[Table 3]

As described above, the chemical polishing liquid maintains good polishing performance until the amount of aluminum dissolved in the chemical polishing liquid becomes 1.5% by mass. It has been confirmed that even if the amount of aluminum dissolved in the chemical polishing liquid increases, chemical polishing can be continuously performed for a long time without adjusting the components in the chemical polishing liquid.

[0042]

As described above, the chemical polishing liquid according to the first aspect of the present invention is a chemical polishing liquid for aluminum or an alloy thereof, which contains an inorganic acid other than nitric acid and a tungsten compound. When chemical polishing is performed by immersing aluminum or aluminum alloy in a liquid, the surface can be polished and smoothed, and gloss can be given to the polished surface. Harmful nitrogen oxides are not generated by the decomposition of nitric acid during the chemical polishing process, and there is no need to add nitric acid to the solution to maintain the nitric acid concentration. Chemical polishing can be continuously performed for a long period of time without adjustment.

According to a second aspect of the present invention, in the first aspect, at least one of phosphoric acid and sulfuric acid is blended as the inorganic acid, so that it has excellent polishing power and can impart good gloss to the polished surface. In addition, the solubility of tungsten compounds and other metal ions in the chemical polishing liquid can be improved to obtain a stable chemical polishing liquid.

According to a third aspect of the present invention, in addition to the first or second aspect, since copper ions are contained, the surface of aluminum or an aluminum alloy can be made more excellent gloss by chemical polishing.

According to a fourth aspect of the present invention, in any one of the first to third aspects, since iron ions are contained, the occurrence of unevenness in gloss on the surface of aluminum or aluminum alloy after chemical polishing is suppressed. Can be done.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, at least one of a calcium ion and a molybdenum ion is contained, so that the surface of aluminum or an aluminum alloy is imparted with further excellent gloss by chemical polishing. Is what you can do.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, a tungsten compound is added in an amount of 0.1 to 0.1 parts by weight in terms of metal tungsten with respect to 100 parts by mass of the total amount of the chemical polishing liquid.
The addition of 01 to 5.0 parts by mass makes it possible to further improve the gloss of the surface of aluminum or an aluminum alloy after chemical polishing and to prevent the tungsten compound from remaining in the liquid without being partially dissolved. Can be done.

According to a seventh aspect of the present invention, in any one of the third to sixth aspects, 0.001 to 0.1 parts by mass of copper ions is added to 100 parts by mass of the total amount of the chemical polishing solution. In addition, the gloss of the surface of aluminum or an aluminum alloy can be further improved, and the occurrence of black precipitation can be prevented.

The invention of claim 8 is characterized in that, in any of claims 4 to 7, 0.01 to 0.50 parts by mass of iron ions are blended with respect to 100 parts by mass of the total amount of the chemical polishing solution. This can further suppress the occurrence of unevenness in gloss on the surface of aluminum or aluminum alloy.

According to a ninth aspect of the present invention, in any one of the second to eighth aspects, 70 to 30 parts by mass of phosphoric acid and 30 to 70 parts by mass of sulfuric acid are added to the total amount of 100 parts by mass of the chemical polishing liquid. In addition, the polishing power by chemical polishing can be further improved.

The tenth aspect of the present invention provides the first to ninth aspects.
In any one of the above, sodium metaphosphate is blended, so that the surface of aluminum or aluminum alloy can be provided with further excellent gloss by chemical polishing, and the dissolution of tungsten compounds and other metal ions in the chemical polishing liquid It is possible to obtain a stable chemical polishing liquid by improving the polishing property.

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Claims (10)

[Claims] 1. A chemical polishing liquid for aluminum or an alloy thereof, comprising an inorganic acid other than nitric acid and a tungsten compound. 2. The chemical polishing liquid according to claim 1, wherein phosphoric acid and sulfuric acid are blended as the inorganic acid. 3. The chemical polishing liquid according to claim 1, wherein the chemical polishing liquid contains copper ions. 4. The chemical polishing liquid according to claim 1, wherein the chemical polishing liquid contains iron ions. 5. The chemical polishing liquid according to claim 1, comprising at least one of calcium ions and molybdenum ions. 6. A tungsten compound in an amount of 0.01 in terms of metal tungsten based on 100 parts by mass of the total amount of the chemical polishing liquid.
2. The composition according to claim 1, wherein the amount is from 5.0 to 5.0 parts by mass.
6. The chemical polishing liquid according to any one of items 1 to 5. 7. The chemical polishing according to claim 3, wherein 0.001 to 0.1 parts by mass of copper ion is blended with respect to 100 parts by mass of the total amount of the chemical polishing liquid. liquid. 8. The chemical polishing according to claim 4, wherein 0.01 to 0.50 parts by mass of iron ions are blended with respect to 100 parts by mass of the total amount of the chemical polishing liquid. liquid. 9. The method according to claim 2, wherein 70 to 30 parts by mass of phosphoric acid and 30 to 70 parts by mass of sulfuric acid are blended with respect to 100 parts by mass of the total amount of the chemical polishing liquid. The chemical polishing liquid as described. 10. The chemical polishing liquid according to claim 1, wherein sodium metaphosphate is blended.