JPH06167441A - Measuring method for adhesion strength of film - Google Patents

Abstract

PURPOSE:To enable accurate evaluation of an adhesion strength of a film by bonding a metal jig to the film formed on a base, by applying a tensile stress thereto and by determining an exfoliation load thereof. CONSTITUTION:A film is formed on a base by a method of every sort and the film and the surface of the base are cut in checkers. To each of islands thus formed, the head part of a jig (ex. a nail-shaped jig having a head area of 3.14mm<2> and a diameter 1mm and made of Ni) having a prescribed joining area is bonded at a normal temperature with a bonding agent. A tensile stress is applied to the jig and an exfoliation load of the film is measured. Each island is preferably a square of 1 to 5mm, though it may be also rectangular or rhombic. The bonding temperature needs only to be the one not causing a change in properties of the film. The bonding agent is preferably a strong one which enables execution of build-up bonding for face bonding of the jig and the film, and it is most preferable that a gel-like bonding agent of cyanoacryl series and a curing agent thereof are used in combination. According to this constitution, only the adhesion strength of the film can be evaluated quantitatively while other effects are excluded. Besides, nonuniformity of the adhesion strength of the film in places can be measured as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the film adhesion strength, and particularly for evaluating the film adhesion strength of members having a coating film on a substrate such as various tools, wear resistant members and electronic members. Publicly available.

[0002]

2. Description of the Related Art Various tools, wear resistant members, wiring boards, etc. are formed on the surface of a base material by various methods for the purpose of improving the wear resistance thereof or forming surface wiring and external terminal brazing pads. The covering member is coated. If the adhesion strength of such a film is insufficient, the reliability of the product will be lost. Therefore, it is important to measure the adhesion strength of the film by some method before shipment as a product.

Conventionally, in evaluating the adhesion of a film, a method of reproducing the actual use conditions and evaluating the quality thereof has been used. For example, in the case of a cutting tool, evaluation was made by the cutting distance until the film peeled off when a cutting test was performed. In the case of a wiring board, terminal pins were brazed to the pads, and the tensile strength of the terminal pins was used for evaluation.

[0004]

With such a method, only evaluation including factors other than film adhesion can be performed. That is, for example, in the case of a cutting tool, it is considerably affected by the non-uniformity of the work material and the sharpness of the cutting edge, and in the case of a wiring board, the film itself is chemically changed, cracked, and swollen due to the heat during brazing. There is a possibility of causing alteration deformation such as. Therefore, the adhesion of the film itself could not be evaluated accurately.

An object of the present invention is to provide a method of accurately evaluating only the adhesion strength of a coating film while eliminating other influences as much as possible.

[0006]

The first means is to form a coating film on a base material by various methods, and cut the coating film and the surface of the base material in a grid pattern, and obtain each of the obtained films. Attach a jig with a specified bonding area to the island with an adhesive at a temperature that does not deteriorate the coating,
A method for measuring film adhesion strength is characterized in that a tensile stress is applied and the peeling load is used to evaluate the adhesion strength of the coating film.

The second means is to form a coating film on each of the islands on the base material, the surface portion of which has been cut in a grid pattern in advance, by various methods, and to modify the coating film with a jig having a predetermined bonding area. A method for measuring the film adhesion strength is characterized in that the adhesion strength of the coating film is evaluated by adhering with an adhesive at a temperature not applied and applying a tensile stress to the peeling load.

In the present invention, each island of the grid is preferably square, but may be rectangular or rhombic as long as the area for joining with the jig is required.
The adhesion temperature may be any temperature as long as the film does not deteriorate, and is not limited to room temperature.

[0009]

Function: By cutting the film surface and the substrate surface into a grid to reduce the area, the stress level required for peeling is reduced and the measurement becomes easier. Also, it becomes possible to measure the local variation in the adhesion strength of the film.

The area to be divided is not particularly limited,
□ 1 to 5 mm is preferable. If it is smaller than □ 1 mm, the accuracy will be poor, and if it is larger than □ 5 mm, the stress level required for peeling will be high and it will be difficult to measure. The jig to be bonded is a nail-shaped or T-shaped metal jig, and a material having a certain tensile strength is preferable, and a Ni wire is particularly preferable.

For the adhesion between the jig and the coating film cut in a grid pattern, a strong adhesive which can adhere to the surface of the jig and the coating film is preferable, and a cyanoacrylic gel adhesive and its adhesive are preferable. It is particularly preferable to use a curing agent in combination.

[0012]

【Example】

- Example 1 - density of 3.3 mg / cm ³ of silicon nitride ceramics as the base material, by a chemical vapor deposition method carried out diamond coating under the conditions shown in A and B of Table 1, the byte chip cutting tool manufacturing did.

Using this tip, a diameter of 15
0 mm cylindrical aluminum alloy (92% Al-8% S
i) at a cutting speed of 1500 m / min. , Feed 0.1m
A cutting test was carried out under the conditions of m / rev and a cutting depth of 0.25 mm.

Separately, a diamond coating is formed on a base material under the same conditions as the above chips to form a coating film, and the coating film and the base material surface are cut with a diamond cutter into a square pattern of 2 mm / square to obtain The collar area is 3.1 on each island.
The flange portion of a nickel Ni jig having a diameter of 4 mm ² and a diameter of 1 mm was bonded at room temperature with a cyanoacrylate adhesive, and tensile stress was applied to measure the peeling load of the coating.

The results of these cutting tests and peeling load measurements are shown in Table 1. In the table, "Cutting distance before peeling"
The numerical value in the column is an average value of cutting distances measured for five chips under the same conditions. The numerical value in the "Peeling load" column is an average value of the peeling load measured at several points of each chip for each chip.

[0016]

[Table 1] As shown in Table 1, in the cutting test, peeling of the coating was observed after cutting 10,000 m in the diamond-coated chip A, but there was no abnormality in the coating after cutting 50000 m in the diamond-coated chip B, and a difference in the coating state appeared. It was

A peeling load of 4 MPa was obtained for the diamond-coated chip A and a value of 25 MPa was obtained for the diamond-coated chip B, which was in good agreement with the cutting test results of both.

Example 2-Diamond-coated chips C and D were manufactured by diamond-coating a base material under the same conditions as in Example 1 except that the base material was a cemented carbide (WC-7% Co). Using these chips, a cutting test and film peeling load measurement were performed under the same conditions as in Example 1. The results are shown in Table 2.

[0019]

[Table 2] As shown in Table 2, in the cutting test, 100
The diamond coating film was peeled off by cutting at 00 m, and the difference between the two could not be judged. On the other hand, as shown in Table 2, the peeling load of the coating film is 5 MPa for diamond-coated chip C and 15 MPa for diamond-coated chip D.
As a measure to improve the adhesion of the diamond film from the viewpoint of coating conditions, we were able to obtain guidelines for setting synthetic conditions that could not be obtained by cutting tests alone.

[0020]

As described above, according to the present invention, the adhesion strength of the coating film can be quantitatively evaluated, and industrially useful effects such as giving important data in developing a coating member having excellent adhesion can be obtained. Of.

Claims (2)

[Claims] 1. A film is formed on a substrate by various methods,
The coating film and the surface of the base material are cut in a grid pattern, and each of the obtained islands is bonded with a jig having a predetermined bonding area with an adhesive at a temperature at which the coating film does not deteriorate, and tensile stress is applied to the coating film with the peeling load. A method for measuring film adhesion strength, which comprises evaluating the adhesion strength of 2. A coating is formed by various methods on each island on a base material whose surface is cut in a grid pattern in advance, and a jig having a predetermined bonding area is bonded to each coating at a temperature at which the coating does not deteriorate. A method for measuring film adhesion strength, which comprises adhering with a chemical agent, applying tensile stress to the film, and evaluating the adhesion strength of the film by the peeling load.