WO2006129489A1

WO2006129489A1 - Method of surface treatment

Info

Publication number: WO2006129489A1
Application number: PCT/JP2006/309918
Authority: WO
Inventors: Sakae Inayoshi; Takeru Nomura; Katsunobu Ishizawa; Shinichi Saito; Manami Yamaguchi
Original assignee: Ulvac, Inc.
Priority date: 2005-05-30
Filing date: 2006-05-18
Publication date: 2006-12-07
Also published as: CN103526276A; CN101031672A; JP2006328516A; TW200704827A; KR20070088516A; JP4799908B2; TWI418656B; KR101116517B1

Abstract

Any matter of chemical liquid, metal, etc. adhering to the surface of a member as a constituent of vacuum treatment apparatus, such as a vacuum vessel, is removed without the use of highly dangerous nitric acid, etc. There is provided a method of surface treatment for a metal part being a constituent of vacuum treatment apparatus as a treatment object, characterized in that the treatment object on its surface is first subjected to electrolytic polishing, partial electrolytic polishing, chemical polishing, pickling or electrolytic pickling and thereafter washed by means of an alkali chelate solution obtained by adding a carboxylic acid or carboxylic salt to a 0.5 to less than 3 wt.% dilute alkali solution up to a concentration of 0.5 to less than 10 wt.%.

Description

Surface treatment method

Technical field

The present invention relates to a surface treatment method for cleaning the surface of a metal part constituting a vacuum processing apparatus.

Background art

[0002] Stainless steel members that make up vacuum processing equipment such as vacuum vessels are welded, machined, etc. to form the shape of the vacuum vessel, and then removes lubricant and oil on the hands in the process. Make a surface treatment to do it! / Speak.

In recent years, the size of the vacuum apparatus has increased, and it has become difficult to process all of the members constituting the large-sized vacuum processing apparatus at one time. Therefore, the present applicant proposed partial electrolytic treatment in Japanese Patent Application No. 2004-219001.

Even in this partial electrolytic treatment, cleaning with pure water or the like is necessary to remove the chemical solution used for the treatment. Metal deposits called smuts on the surface during partial electrolytic treatment (in the case of stainless steel, oxides and salts of Cr, Ni, Fe, etc. are unevenly attached) use a high-pressure jet. In a vacuum atmosphere that is difficult to remove even after washing with pure water, the metallic deposits may be released into the space, or may be struck by charged particles during the subsequent film formation. As a result, there was a problem that the vacuum apparatus could be contaminated. In order to remove these metallic deposits, there was a problem that after partial electrolytic treatment, it was necessary to use nitric acid, which is highly dangerous when handled. In addition to the above-mentioned partial electrolytic treatment, there are conventional electropolishing and electrochemical polishing as the surface treatment method of the apparatus. In any of these methods, the above-mentioned smut is applied to the metal surface after the treatment. Adheres. If the smut is left as it is, there is a problem that it may be released into the space and contaminate the vacuum apparatus as in the case of partial electrolytic treatment. In addition, in order to remove these metallic deposits, there is a problem that, after partial electrolytic treatment, there is a high risk of handling, and nitric acid must be used for cleaning. Disclosure of the invention Problems to be solved by the invention

[0003] Therefore, the present invention solves the above-mentioned conventional problems, and deposits such as chemicals and metals adhering to the surface of members constituting a vacuum processing apparatus such as a vacuum vessel are highly dangerous! The objective is to remove it without using nitric acid or the like and without immersing it.

Means for solving the problem

[0004] In order to solve the above problems, the present inventors have intensively studied, and based on the knowledge that the above problems can be solved by using an alkaline chelating solution instead of nitric acid, The solution was found as follows.

That is, the surface treatment method of the present invention is a surface treatment method in which a metal part constituting a vacuum processing apparatus is an object to be processed as described in claim 1, and the surface of the object to be processed is electrolyzed. After polishing, partial electrolytic treatment, chemical polishing, pickling or electrolytic pickling, the concentration should be 0.5 wt% or more and less than 10 wt% in dilute alkali solution of 0.5 wt% or more and less than 3 wt%. The surface of the object to be treated is washed with an alkaline chelating solution obtained by adding rubonic acid or carboxylate.

The surface treatment method according to claim 2 is characterized in that, in the surface treatment method according to claim 1, the temperature of the alkaline chelating solution is 10 to 80 ° C.

The invention's effect

[0005] According to the surface treatment method of the present invention, the surface of an object to be treated can be cleaned with a relatively simple configuration. In addition, there is less danger because deposits such as metals on the surface of the object to be treated can be removed without using nitric acid. Furthermore, if a vacuum processing apparatus is constituted by the surface-treated member according to the present invention, the gas released can be reduced in a vacuum atmosphere.

Brief Description of Drawings

[0006] FIG. 1 is a graph showing a change in gas release rate per unit area in Example 3

Explanation of symbols

[0007] 1 Gas release rate per unit area of sample treated with chelating solution

2 Gas release rate per unit area of a sample that has been treated with a chelating solution BEST MODE FOR CARRYING OUT THE INVENTION

[0008] The present invention is a surface treatment method using a metal part constituting a vacuum processing apparatus as an object to be processed, wherein the surface of the object to be processed is subjected to electrolytic polishing, partial electrolytic treatment, chemical polishing, pickling or electrolysis. After pickling, a carboxylic acid or a carboxylic acid salt is added to a dilute alkaline solution of 0.5 wt% or more and less than 3 wt% so that the concentration becomes 0.5 wt% or more and less than 10 wt%. The surface of the object to be treated is washed with the obtained alkaline chelating solution.

The metal parts constituting the vacuum processing apparatus are not particularly limited as long as they are parts placed in a vacuum processing environment. An example is a metal container. Examples of the metal include stainless steel, aluminum alloy, titanium alloy, and the like. As the treatment medium, the material and the shape are not limited as long as a current can flow between the electrodes. For example, a nonwoven fabric can be used.

[0009] The electropolishing, chemical polishing, pickling or electrolytic acidity are known, and the partial electrolytic treatment is to connect an object to be processed to the anode side of the power source and to be processed to the cathode side. This means that the surface of the object to be treated is electropolished by connecting a treatment medium for contacting the electrolyte to the surface of the object and passing a direct current between the electrodes via the electrolyte. More preferably, the surface roughness (R) of the object to be treated is 0.1 m by the treatment. In addition, concrete max

An example is described in Japanese Patent Application No. 2004-219001!

The electrolytic solution used for the electropolishing or partial electrolytic treatment includes at least one of an inorganic acid, an organic acid, an inorganic acid salt, and an organic acid salt. Specifically, phosphoric acid, sulfuric acid, Examples thereof include ammonium citrate, ammonium chloride, ammonium dihydrogen phosphate, ammonium sulfate, sodium nitrate, and citrate.

Further, as a treatment medium that can be used for the partial electrolysis treatment, a material and a shape are not limited as long as a direct current can be passed between the electrodes. For example, a nonwoven fabric can be used.

The electrolytic current density in the electrolytic polishing or the partial electrolytic treatment varies depending on the object to be treated. For example, in the case of stainless steel, it is 0.1 to 0.5 AZcm ² .

[0010] Examples of the alkaline chelating solution include dilute alkaline aqueous solutions such as sodium hydroxide and citrate. And solutions containing sodium citrate, ammonium oxalate, sodium phthalate, potassium tartrate, sodium dalconate, malic acid, and the like.

[0011] The alkaline chelating solution is preferably set to 10 ° C to 80 ° C. If the temperature is lower than 10 ° C, the reaction rate is remarkably reduced. If the temperature is higher than 80 ° C, the handleability is poor and there is a risk of alkaline corrosion.

[0012] The treatment with the alkaline chelating solution is preferably performed by soaking it in a treatment medium such as cloth. This is because the surface treatment can be performed locally even if the workpiece is enlarged.

Example 1

[0013] SUS304 (300mm X 150mm X 1mm) to be processed is subjected to partial electrolytic treatment with sodium dihydrogen phosphate and sodium nitrate neutral salt. The following treatment was performed with the chelating solution.

a) 1 wt ^_0/0 of Mizusani匕sodium solution, the solution was added sodium Kuen acid to a concentration of 3 wt%

b) A solution of malic acid added to a 1 wt% sodium hydroxide solution to a concentration of 3 wt%

Each chelating solution was heated to 40-50 ° C and included in the cleaning cloth to wipe the entire surface of the object to be treated. After the wiping was completed, high-pressure jet cleaning was performed with pure water heated to 50 ° C., and the chemical solution and alkaline chelating solution used for the electropolishing were removed. And it dried with the liquid nitrogen vaporized as finishing.

In order to confirm the effect of removing smut, ion chromatography analysis was performed. In detail, after wiping the entire surface with a cleaning cloth soaked with pure water for the object to be treated before and after cleaning, 100 ml of pure water soaked in the cleaning cloth was extracted, and each surface area per unit area was extracted. The amount of water was calculated.

The results are shown in Table 1 for a and in Table 2 for b.

[0014] [Table 1] (ng- cm ² ) cation Na ⁺ NH ₄ + K ⁺ Mg Ca ²⁺

NaH ₂ P0 ₄ Before removal 25.1 26.7 19.6 ND 22.1

After removal 1.7 1.8 0.2 ND ND

NaN0 ₃ Before removal 33.1 35.9 22.7 ND 34.2

After removal 1.5 0.5 0.1 ND ND

(ng- cm ² ) anion F— (: N0 ₂ — Br— N0 ₃ "P0 ₄ ³ — S0 ₄ ² "

78.9

NaH ₂ P0 ₄ Before removal 39.4 77.2 12.4 682.3 247.2 332.5 After removal 0 1.3 3.7 ND 1.3 4.9 2.6 Before removal 77.3 34.1 789.5 22.7 542 324.1 246.1

NaN0 ₃

After removal 1.8 3.7 7.6 ND 5.3 1.9 3.8

[Table 2]

(ng- cm ² ) cation Na ⁺ NH ₄ + K ⁺ Mg Ca ²⁺

NaH ₂ P0 ₄ Before removal 19.1 18.7 22.6 ND 27.1

After removal 2.8 12.2 0.7 ND ND

NaN0 ₃ Before removal 32.1 21.9 1 1.9 ND 23.1

After removal 1.9 2.8 0.4 ND ND

(ng- cm ² ) anion F— (: N0 ₂ — Br— N0 ₃ "P0 ₄ ³ — S0 ₄ ² "

NaH ₂ P0 ₄ Before removal 85.9 33.3 74.2 17.4 789.1 251.6 348 After removal 0 1.9 4.7 ND 1.9 6.9 1.6

57.3 19.9 54.7 1 1.6 967.1 104.5 1 27.5

Before NaN0 ₃ removal

After removal 2.1 4.1 5.5 ND 6.3 2.5 1.8

[0016] From Table 1 and Table 2 above, after the removal of the smut, the strength of the Na + was reduced as well as the ani concentration that became an adhesion salt of the alloy component compared to before the removal.

Example 2

[0017] SUS304 (300mm x 150mm x lmm) to be treated was subjected to partial electrolytic treatment with sodium dihydrogen phosphate and sodium nitrate neutral salt, and red and blue smut generated on the surface. The following treatments were performed with the following two chelating solutions.

a) A solution of sodium citrate added to a 1% by weight sodium hydroxide sodium hydroxide solution heated to 40 ° C to a concentration of 3% by weight

b) A solution obtained by adding phosphonic acid to a concentration of 3% by weight to a 1% by weight sodium hydroxide sodium hydroxide solution heated to 40 ° C.

The chelating solutions a and b were included in the cleaning cloth, and the entire surface of the workpiece was wiped. After the wiping, in order to confirm the effect of removing the smut, each used cleaning cloth was immersed in 100 ml of pure water, and the elution amount of the metal component in each chelating solution was extracted into pure water. Then, the metal to be analyzed was measured by atomic absorption analysis as Fe, Cr, Ni, which are components of stainless steel alloy.

The detected stainless steel component is the smut partial force, and the stainless steel itself is the force. In order to show that there was no smut, the smut was removed with a 30% by weight nitric acid solution, washed with water, treated with a, and the washing cloth used in the treatment with a was extracted, and this was designated c.

The results are shown in Table 3.

[0018] [Table 3]

[0019] From the above results, Fe and Cr were detected from the cleaning cloth using a and b. On the other hand, in c, the elements constituting Fe, Cr and Ni stainless steel were not detected.

From these results, it was found that smut that does not damage the workpiece itself was removed in a and b.

Example 3

[0020] A SUS304 (300mm x 150mm x 1mm) workpiece was subjected to partial electrolytic treatment with ammonium dihydrogen phosphate and a neutralized salt of sodium nitrate, and the concentration was adjusted to 1 wt% sodium hydroxide solution. The solution obtained by adding sodium citrate to 3% by weight was soaked into a cleaning cloth and wiped, and the gas release characteristics were evaluated.

[0021] The gas release characteristics were evaluated by the change in the gas release rate per unit area released while the temperature was raised from room temperature to 500 ° C using the temperature programmed desorption method.

Fig. 1 is a graph showing the change in the gas release rate per unit area. In the figure, 1 is the gas release rate of the sample treated with the chelate solution, and 2 in the figure is the number of samples not treated. The gas release rate of the sample.

From Fig. 1, the sample treated with the chelating solution showed a lower gas release rate, especially at temperatures above 250 ° C, compared to the sample that had been treated. The source of gas released in this temperature range was removed by treatment with chelating solution.

Example 4

[0022] An SUS304 (300mm x 150mm x 1mm) workpiece was electropolished with 70% phosphoric acid and 30% sulfuric acid solution. The following processing was performed.

a) A solution of sodium citrate added to a 1% sodium hydroxide solution to a concentration of 3%

The chelate solution was heated to 40 ° C. to 50 ° C. and included in a clean cloth to wipe the entire surface of the object to be treated. After the wiping was completed, high-pressure jet cleaning using pure water heated to 50 ° C was performed, and the chemical solution used for electropolishing and the alkaline chelate solution were removed. As a finish, it was dried with vaporized liquid nitrogen.

In order to confirm the effect of removing smut, ion chromatography analysis was performed. Specifically, for the object to be treated before and after cleaning, after wiping the entire surface with a clean cloth soaked with pure water, 100 ml of pure water soaked in the clean cloth is extracted, and each ion per unit area is extracted. The amount was calculated. The results are shown in the table.

[0023] [Table 4]

(ng-cm ² )

[0024] From the above table, it can be seen that after removal of the smut, both cations of Na +, as well as arions, which are adhering salts of the alloy components, are reduced after removal of the smut.

Claims

The scope of the claims

[1] A surface treatment method using a metal part constituting a vacuum processing apparatus as an object to be processed, wherein the surface of the object to be processed is subjected to electrolytic polishing, partial electrolytic treatment, chemical polishing, pickling or electrolytic pickling. Subsequently, an alkali obtained by adding a carboxylic acid or a carboxylic acid salt to a dilute alkali solution of 0.5 wt% or more and less than 3 wt% so as to have a concentration of 0.5 wt% or more and less than 10 wt%. A surface treatment method comprising washing the surface of the object to be treated with a chelating solution.

[2] The surface treatment method according to [1], wherein the temperature of the alkaline chelating solution is 10 to 80 ° C.