JP2007154218A - Film separating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film separating method capable of separating a chemical-converted film by a simple method. <P>SOLUTION: In the film separating method, a nickel phosphate chemical-converted film (2) is separated from a sample (3) with the nickel phosphate chemical-converted film (2) deposited on a surface of a bendable test piece (1). The test piece (1) consists of a material containing at least one of chromium and aluminum, and by bending the sample (3), the nickel phosphate chemical-converted film (2) is broken, and the nickel phosphate chemical-converted film (2) is peeled off from a broken part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a film separation method for separating a nickel phosphate chemical conversion coating from a sample having a nickel phosphate chemical conversion coating formed on the surface of a test piece.

  The nickel phosphate chemical conversion coating (hereinafter also simply referred to as “chemical conversion coating”) is, for example, a protective film for improving the wear resistance, corrosion resistance, etc. of the material to be processed, or gold plating on the material to be processed. It is used as a base for application. It is important from the aspect of quality control to analyze the components of the chemical conversion coating. For example, in Patent Document 1, a chemical conversion treatment film is dissolved using an ammoniacal ammonium dichromate aqueous solution, the amount of chemical conversion treatment film is determined from the mass difference between the steel sheets before and after dissolution, and the film composition is determined from elemental analysis of the solution. Is described. However, in the above method, since the chemical conversion film is dissolved, it is only possible to obtain the amount of film adhered and the amount of elements contained in the film, and evaluations for more chemical conversion films (for example, chemical conversion treatment). It is difficult to evaluate the crystallinity of the film.

In order to solve the above-mentioned problem, Patent Document 2 discloses that a sample in which a chemical conversion film is formed on the surface of a zinc-based plated steel sheet is immersed in an organic solvent containing iodine, and only the zinc-based plating layer is dissolved. A film separation method for separating a treated film in a film state has been proposed.
JP-A-7-138864 JP 2001-279463 A

  However, in the method described in Patent Document 2, it is necessary to infiltrate the organic solvent into the interface between the chemical conversion film and the zinc-based plating layer, so that it takes time to separate the film, and it is necessary to remove the organic solvent by filtration. Therefore, there is a risk that the number of processing steps will increase.

  This invention solves the said conventional subject, and provides the film separation method which can isolate | separate a chemical conversion treatment film by a simple method.

The film separation method of the present invention is a film separation method for separating the nickel phosphate chemical conversion coating from a sample in which a nickel phosphate chemical conversion coating is formed on the surface of a foldable test piece,
The test piece is made of a material containing at least one of chromium and aluminum,
The nickel phosphate chemical conversion treatment film is broken by bending the sample, and the nickel phosphate chemical conversion treatment film is peeled off from the broken portion.

  According to the film separation method of the present invention, since the chemical conversion film can be separated by a simple method, the processing time and the number of processing steps can be reduced.

  In the method for separating a film according to the present invention, a sample having a nickel phosphate chemical conversion coating (chemical conversion coating) formed on the surface of a bendable test piece is bent to break the chemical conversion coating and then form a chemical conversion from the fractured portion. Remove the treatment film. Thereby, since the chemical conversion treatment film can be easily separated without using an organic solvent, it is possible to reduce the processing time and the number of processing steps as compared with the conventional method. In addition, when bending a sample, it is preferable that the curvature radius of the bending location of a sample is 0.1-50 mm. It is because peeling of a chemical conversion treatment film becomes still easier. Moreover, the thickness of a chemical conversion treatment film is about 1-100 micrometers, for example.

  The test piece is made of a material containing at least one of chromium and aluminum. For example, a test piece made of a material such as chromium, a chromium alloy, aluminum, an aluminum alloy, and stainless steel can be used. Since chromium and aluminum have a strong binding force with oxygen, a test piece made of a material containing at least one of chromium and aluminum has a dense oxide film (passive film) formed on the surface thereof. Since this oxide film has the same compactness as glass, the adhesion between the oxide film and the chemical conversion film (for example, electroless plating film) is low. Therefore, by bending the sample as described above, the chemical conversion coating can be easily peeled off from the test piece starting from the broken portion. In addition, content of chromium or aluminum in a test piece is 9 mass% or more, for example, Preferably it is 9-25 mass%.

  The shape of the test piece is preferably a plate shape or a rod shape. This is because the test piece can be easily bent. When using a plate-shaped test piece, the thickness should just be about 0.1-1 mm, for example. Moreover, when using a rod-shaped test piece, the diameter should just be about 0.1-5 mm, for example.

  When the chemical conversion coating is formed by electroless plating, electroless plating is performed by immersing a container filled with a test piece and a dummy material that promotes electroless plating on the test piece in a bath filled with electroless plating solution. It is preferable to perform the test while the test piece and the dummy material are brought into contact with each other by swinging the container. As described above, the test piece used in the present invention has low adhesion to the chemical conversion treatment film, but by treating the test piece together with the dummy material, the chemical treatment film is grown from the dummy material as a starting point. Electroless plating can be performed. In addition, by performing electroless plating while swinging, bubbles generated during the electroless plating reaction can be removed while the test piece and the dummy material are in contact with each other. Dust can be prevented.

  It is preferable that through holes are formed in the bottom and side surfaces of the container. Since the exchange between the electroless plating solution in the container and the electroless plating solution in the bath is promoted, the plating process can be performed stably. As such a container, for example, a container formed in a mesh basket shape can be used. The material of the container is not particularly limited, and for example, polypropylene or polyethylene can be used. In addition, the diameter of the said through-hole should just be about 0.5-10 mm, for example.

  The dummy material is preferably made of a material containing a group 8 element such as iron or nickel. This is because the Group 8 element has high reactivity with the electroless plating solution, and thus the effect of promoting electroless plating is enhanced. The shape of the dummy material is preferably substantially spherical. This is because the contact between the test piece and the dummy material becomes a point contact, and thus the electroless plating on the test piece is performed uniformly. In this case, the diameter of the dummy material may be about 0.6 to 20 mm, for example.

  Embodiments of the present invention will be described below with reference to the drawings. Note that in the drawings to be referred to, components having substantially the same function are denoted by the same reference numerals for the sake of brevity, and redundant description may be omitted.

  First, a film separation method according to an embodiment of the present invention will be described. 1A and 1B are cross-sectional views for explaining a film separation method according to an embodiment of the present invention.

  In the film separation method according to one embodiment of the present invention, the sample 3 (FIG. 1A) in which the chemical conversion film 2 is formed on the surface of the bendable test piece 1 is bent as shown in FIG. 1B. 2 is broken, and the chemical conversion film 2 is peeled off from the broken portion. Thereby, since the chemical conversion treatment film 2 can be easily separated without using an organic solvent, the processing time and the number of processing steps can be reduced as compared with the conventional method.

  The test piece 1 is made of a material containing at least one of chromium and aluminum. For example, a test piece made of a material such as chromium, a chromium alloy, aluminum, an aluminum alloy, and stainless steel can be used. Since chromium and aluminum have a strong binding force with oxygen, the test piece 1 made of a material containing at least one of chromium and aluminum has a dense oxide film (passive film) formed on the surface thereof. Since this oxide film has the same degree of denseness as glass, the adhesion between the oxide film and the chemical conversion film 2 is lowered. Therefore, by bending the sample 3 as described above, the chemical conversion treatment film 2 can be easily peeled from the test piece 1 starting from the broken portion.

  Next, a suitable method for forming the chemical conversion film 2 on the surface of the test piece 1 will be described. FIG. 2 to be referred to is a cross-sectional view for explaining a method of forming the chemical conversion film 2. In addition, the method demonstrated below is a method of forming the chemical conversion treatment film 2 by electroless plating.

  As shown in FIG. 2, in this method, the container 10 charged with the test piece 1 and the dummy material 11 (for example, an iron ball) that promotes the electroless plating on the test piece 1 is filled with the electroless plating solution 21. The test piece 1 and the dummy material 11 are brought into contact with each other by dipping in the bathtub 20 and swinging the container 10. As the container 10, a container formed in a mesh basket shape is used in this method. Further, the swinging direction of the container 10 is a direction substantially perpendicular to the liquid level of the electroless plating solution 21, and the swinging speed may be about 0.1 to 0.5 seconds / cycle, for example. The swinging method is not particularly limited, and it may be swung manually or a swinging device may be used. If this method is used, the electroless plating on the test piece 1 can be performed by growing the chemical conversion film 2 (see FIG. 1A) starting from the dummy material 11.

  Examples of the present invention will be described below. In addition, this invention is not limited to the Example shown below.

  In this example, the chemical conversion coating 2 was formed by the method shown in FIG. For the test piece 1, plate-like stainless steel (manufactured by SUS304) having a length of 100 mm × width of 20 mm × thickness of 0.2 mm was used. As the dummy material 11, an iron ball having a diameter of 6 mm was used. As the container 10, a mesh cage made of polypropylene was used. In this mesh basket container, the diameter of the bottom of the mesh cage portion is 100 mm, the height of the mesh cage portion is 200 mm, and the diameter of the through hole provided in the mesh cage portion is 3 mm. The bathtub 20 has a volume of 430 L, and 400 L of electroless nickel plating solution (manufactured by Uemura Kogyo Co., Ltd., model number: Nimden DX) is placed in the bathtub 20 and plated by the following procedure. Went.

  First, the test piece 1 and the dummy material 11 were put into the container 10. At this time, the volume ratio between the test piece 1 and the dummy material 11 was set to be test piece 1: dummy material 11 = 1: 3. The container 10 containing the test piece 1 and the dummy material 11 is immersed in an alkaline degreasing solution at 55 ° C. for 3 minutes, washed with water for 1 minute, and then placed in 40 ° C. hydrochloric acid (hydrogen chloride concentration: about 14%). It was immersed for 3 minutes and washed with water for 1 second. And this was immersed in the said electroless nickel plating solution, and the container 10 was rock | fluctuated manually for 2 minutes. At this time, the swinging direction of the container 10 was set to a direction substantially perpendicular to the liquid level of the electroless nickel plating solution, the swinging amplitude was 25 cm, and the swinging speed was 0.3 seconds / cycle. And the container 10 in which this test piece 1 and the dummy material 11 were thrown in was attached to the rocking | swiveling apparatus, and electroless nickel plating was performed, rocking the container 10 in the said electroless nickel plating solution (processing time: 1 hour). In this case, the rocking speed was 0.5 seconds / cycle, and the temperature of the electroless nickel plating solution was kept in the range of 86 to 90 ° C. By this plating treatment, a chemical conversion treatment film 2 having a thickness of 12 μm was formed on the surface of the test piece 1.

  The sample 3 covered with the chemical conversion film 2 was washed with water for 1 minute, immersed in isopropyl alcohol for 20 seconds, and then dried in an atmosphere at 110 ° C. for 30 minutes. Then, the chemical conversion treatment film 2 was broken by bending the sample 3, and the chemical conversion treatment film 2 was peeled off in the state of the film from the broken portion. When the sample 3 was bent, the radius of curvature of the bent portion of the sample 3 was 0.5 mm.

  In addition, instead of plate-like stainless steel, the test piece 1 is plated using wire-like stainless steel (diameter: 0.5 mm, length: 20 m) under the same conditions as above, and the chemical conversion coating 2 is formed in the same manner. Also when peeled, the chemical conversion film 2 could be separated in the state of the film.

  INDUSTRIAL APPLICABILITY The present invention is useful as a film separation method for separating a nickel phosphate chemical conversion coating film in a film state from a sample having a nickel phosphate chemical conversion coating film formed on the surface of a test piece.

A and B are sectional views for explaining a film separation method according to an embodiment of the present invention. It is sectional drawing for demonstrating the suitable method of forming a chemical conversion treatment film on the surface of a test piece.

Explanation of symbols

1 Test piece 2 Chemical conversion coating (nickel phosphate chemical conversion coating)
3 Sample 10 Container 11 Dummy 20 Bath 21 Electroless plating solution

Claims (6)

A film separation method for separating the nickel phosphate chemical conversion coating from a sample having a nickel phosphate chemical conversion coating formed on the surface of a bendable test piece,
The test piece is made of a material containing at least one of chromium and aluminum,
A method of separating a film, comprising bending the sample to break the nickel phosphate chemical conversion coating, and peeling the nickel phosphate chemical conversion coating from the broken portion.   The film separation method according to claim 1, wherein a shape of the test piece is a plate shape or a rod shape. The nickel phosphate chemical conversion coating is formed by electroless plating,
The electroless plating is performed by immersing a container filled with the test piece and a dummy material that promotes electroless plating on the test piece in a bath filled with an electroless plating solution, and swinging the container to The film separation method according to claim 1, wherein the method is performed while bringing the test piece and the dummy material into contact with each other.   The film separation method according to claim 3, wherein through holes are formed in a bottom surface and a side surface of the container.   The film separation method according to claim 3, wherein the dummy material is made of a material containing a group 8 element.   The film separation method according to claim 3, wherein the dummy material has a substantially spherical shape.

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