Method for evaluating adhesion performance of diamond film

Abstract

To provide a method for evaluating adhesion performance of a diamond film capable of surely and easily evaluating the adhesion performance of the diamond film without damaging an evaluation testing device and a testing instrument.SOLUTION: A substrate W coated with a diamond film 3 is pressed against a tip saw 2 while rotating the tip saw 2 having a plurality of diamond tips 1 on its outer peripheral surface. In this case, the chip saw 2 is a wheel-type chip saw 2, and adhesion performance of the diamond film is evaluated by pressing the substrate W toward the chip saw 2 side so as to be perpendicular to a tangential direction H of the rotating chip 1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for evaluating the adhesion performance of a diamond film coated on the surface of a tool. [Background technology]

[0002] Conventionally, a Rockwell hardness measurement test has been used as a method for evaluating the adhesion of a diamond film coated on the surface of a substrate. In this hardness measurement test, a Rockwell indenter is pressed into the diamond film to be measured, and the adhesion is evaluated from the indentation load and the length of the crack growth. In addition, Patent Document 1 discloses a method in which a laser is irradiated onto the surface of the diamond film and the adhesion is calculated from the area of ​​the diamond film removed by the laser irradiation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-248454 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional adhesion evaluation method using a Rockwell hardness tester, the diamond indenter that presses against the diamond film surface can break before cracks appear on the diamond film surface. This makes it impossible to evaluate the adhesion of the diamond film. Furthermore, the length of the cracks that appear varies depending on the film thickness of the diamond film, which can lead to variations in the adhesion evaluation results (numerical values).

[0005] Therefore, an object of the present invention is to provide a method for evaluating the adhesion performance of a diamond film, which can reliably and easily evaluate the adhesion of a diamond film without damaging the evaluation test device or test equipment. [Means for solving the problem]

[0006] The method for evaluating the adhesion performance of a diamond film of the present invention evaluates the adhesion performance of a diamond film by rotating a chip saw equipped with multiple diamond tips on its outer surface while pressing a substrate coated with a diamond film against the chip saw.

[0007] When the tip saw used is a wheel-type tip saw, the substrate is pressed against the tip saw so that the direction is perpendicular to the tangential direction of the rotating tip. [Effects of the Invention]

[0008] The method for evaluating the adhesion performance of a diamond film of the present invention evaluates the adhesion performance of a diamond film by rotating a wheel-type tipped saw equipped with multiple diamond tips on its outer periphery while pressing a substrate coated with a diamond film perpendicularly against the tipped saw. This has the effect of enabling reliable and easy evaluation of the adhesion of a diamond film without damaging the evaluation test device or testing equipment. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic overall view showing the diamond film of the present invention when evaluating its adhesion performance. [Figure 2] FIG. 2 is a partially enlarged view of FIG. [Figure 3] 1 is a graph showing the amount of peeling of the diamond film in the example. DETAILED DESCRIPTION OF THE INVENTION

[0010] A method for evaluating the adhesion performance of a diamond film according to one embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows a schematic overall view of the method for evaluating the adhesion performance of a diamond film according to the present invention, and Fig. 2 shows an enlarged view of a portion of Fig. 1.

[0011] When evaluating the adhesion performance of a diamond film according to the present invention, a substrate W having a surface coated with a diamond film 3 and a tipped saw 2 having a plurality of diamond tips 1 on its outer periphery are prepared in advance. Below, the substrate W, the tipped saw 2, and a method for evaluating the adhesion performance of a substrate W coated with a diamond film using the tipped saw 2 will be described in detail.

[0012] ≪Base material W≫ The substrate W is a material whose base material is an iron-based alloy or cemented carbide alloy, such as high-speed tool steel or die steel used in tools. The substrate W may have any shape, such as a rectangular parallelepiped (cube) or a cylindrical shape. The surface of the substrate W is coated with a diamond film 3, as shown in FIGS. 1 and 2. In this case, the term "diamond film" includes amorphous diamond films and diamond-like carbon (DLC) films. The film thickness of the diamond film coated on the surface of the substrate W is preferably about 2 to 20 μm.

[0013] <Tip Saw 2> The tipped saw 2 is a disc-shaped saw blade, and as shown in Figure 1, is a cutting tool with many hard tips 1 attached to the outer periphery of a disc-shaped base member. Generally, the tips are made of a high-hardness material or are diamond-coated in order to cut high-hardness materials such as high-speed tool steel. For example, a commercially available tipped saw with a diameter of 100 to 200 mm, a blade thickness of 1 to 2 mm, and 10 to 40 tips attached can be used.

[0014] <Diamond film adhesion performance evaluation method> The method for evaluating the adhesion performance of a diamond film according to the present invention involves rotating (in a rotation direction RT) a wheel-type chip saw 2 having a plurality of diamond chips 1 on its outer peripheral surface as described above, as shown in Figure 1, while pressing a substrate W having a diamond film 3 coated on its surface against the chip saw (pressing force F).

[0015] The substrate W is pressed against the rotating tip 1 in direction C (downward in the drawing) so that the direction V is perpendicular to the tangential direction H of the rotating tip 1. It is also preferable that the substrate W is pressed intermittently against the tip 1 of the tip saw 2. In this case, the rotation speed of the tip saw 2 is preferably in the range of 100 to 10,000 rpm, and the load when pressing the substrate W into the tip saw 2 (pressing load F shown in FIG. 1) is preferably in the range of 1 to 100 N. [Example]

[0016] Using the method for evaluating the adhesion performance of a diamond film according to the present invention, a diamond film adhesion evaluation test (hereinafter referred to as the "main test") was carried out on a plurality of samples, and the test results will be explained using the drawings. The samples used in the main test were six in total, each consisting of a base material (WC-based cemented carbide) coated with a diamond film (diamond film thickness: 12-15 mm).

[0017] Each sample was pressed horizontally against the diamond film of the aforementioned samples with a specified load (3N: F in Figure 1) so that intermittent impacts were applied by the tip of a tipped saw (rotation speed: 200 rpm). The detailed conditions for this test were as follows: As a standard for diamond film adhesion, samples in which the diamond film had peeled off to a thickness of less than 300 μm were judged to have "good adhesion," and samples in which the diamond film had peeled off to a thickness of 300 μm or more were judged to have "poor adhesion." Figure 3 shows a graph showing the amount of diamond film peeling off for the six samples (N1 to N6) used in this test.

[0018] As a result of this test, the thickness of the diamond film that peeled off from three samples (N1, N2, N3) was in the range of 134 to 269 μm, and these samples were judged to have "good adhesion." In contrast, the thickness of the diamond film that peeled off from the remaining three samples (N4, N5, N6) was in the range of 504 to 593 μm, and these samples were judged to have "poor adhesion."

[0019] From the above test results, it was found that the method for evaluating the adhesion performance of diamond films according to the present invention can easily evaluate the adhesion of substrates coated with diamond films by using a chip saw equipped with multiple chips on its outer peripheral surface to apply intermittent impacts to the diamond film that mimic cutting processes using actual tools such as drills and end mills.

[0020] In addition, the delamination morphology of diamond films obtained using this evaluation method is similar to that obtained when conventional surface hardness measurements are performed. This allows correlation with, for example, Rockwell hardness test results, making it possible to quantitatively evaluate the adhesion of diamond films instead of the conventional Rockwell hardness test. [Explanation of symbols]

[0021] 1 chip 2. Tip saw 3. Diamond film C Tip movement direction F: Indentation load on substrate RT··Tip saw rotation direction H...Tangential direction V...Vertical direction W...Base material

Claims

1. A method for evaluating the adhesion performance of a diamond film, characterized by rotating a chip saw equipped with multiple diamond tips on its outer surface while pressing a substrate coated with a diamond film against the chip saw.

2. The method for evaluating the adhesion performance of a diamond film as described in claim 1, characterized in that the chip saw is a wheel-type chip saw, and the substrate is pressed against the chip saw in a direction perpendicular to the tangential direction of the rotating chip.

3. 3. The method for evaluating adhesion performance of a diamond film according to claim 2, wherein the substrate is intermittently pressed against the tip of the tip saw.

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