JP5353613B2 - Coated cemented carbide member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new coated cemented carbide member which has improved adhesion between a base material made of a cemented carbide and a hard film by forming the surface of the base material into a predetermined rugged face. <P>SOLUTION: The coated cemented carbide member includes: the base material 10 made of a cemented carbide composed of a hard phase 12 containing tungsten carbide and a binder phase 11 containing transition metal; and the hard film 2 covered on the surface of the base material 10. The surface of the base material 10 covered with the hard film 2 is a rugged face 10f having a recessed part 12<SP>-</SP>from which the hard phase 12 is lost, and when the average particle diameter of WC is defined as X[&mu;m], the maximum depth of the recessed part 12<SP>-</SP>as Y[&mu;m], and the area ratio of the binder phase 11 in the rugged face 10f as [Z%], by controlling the values of X, Y and Z to prescribed ranges, an anchor effect improves the adhesion between the surface of the base material 10 and the hard film 2. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a coated cemented carbide member obtained by coating a hard film of an inorganic compound on the surface of a substrate made of cemented carbide.

  A cemented carbide formed by sintering a mixed powder of metal carbide powder and metal powder is excellent in mechanical properties such as hardness and strength, and is excellent in wear resistance and corrosion resistance. Therefore, it is used not only for cutting tools but also for dies that require high accuracy. In addition, in order to complement the required characteristics that cannot be satisfied by the cemented carbide alone and improve the quality according to the application of the cemented carbide, the surface of the cemented carbide is often used with various coatings.

  For example, a member in which a hard film such as an amorphous carbon (diamond-like carbon: DLC) film or titanium nitride is coated on the surface of a substrate made of a cemented carbide is widely used. However, if the surface of the base material is simply coated on the surface of a general cemented carbide, the difference in thermal expansion coefficient between the base material and the coating film is large, and chemical bonding occurs at the interface between the two. Therefore, the coating film is easy to peel off. Various studies have been made so far in order to improve the adhesion between the cemented carbide and the coating film to prevent the peeling of the coating film.

  In order to improve the adhesion between the base material and the coating film, for example, the anchor effect by the unevenness formed on the surface of the base material on which the film is coated is effective. In general, cemented carbide is composed of a hard phase mainly composed of tungsten carbide (WC) and a binder phase mainly composed of an iron group metal such as cobalt (Co). Therefore, the surface of the base material made of cemented carbide is corroded by using the difference in the susceptibility to corrosion between the hard phase and the binder phase, thereby forming irregularities on the surface of the base material.

  In Patent Document 1, the surface of a cemented carbide substrate having a hard phase of 99% by weight or more and the balance consisting of a binder phase and impurities is subjected to electrolytic corrosion with an alkaline solution and corrosion with an acid solution. Concavities and convexities are formed on the surface of the material. The hard phase is corroded in the alkaline solution and the binder phase is corroded in the acid solution, and these interactions increase the unevenness, and the unevenness on the surface of the substrate improves the adhesion and adhesion between the substrate and the coating film. ing.

  In Patent Document 2, a cemented carbide containing WC as a main component and Co as a binder phase component and having a dispersed phase that is harder to be etched than WC is used as a base material. Unevenness is formed on the surface of the substrate by electrolytic etching. Electrolytic etching elutes the WC and the binder phase component on the surface of the base material, forming a protrusion with the disperse phase remaining undissolved at the tip and forming an uneven surface on the surface (FIGS. 1 and 2 of Patent Document 2).

JP-A-10-226597 JP 2000-144451 A

  In Patent Document 1 and Patent Document 2, as a method for forming an uneven surface, a binder phase that bonds WC particles constituting a hard phase is dissolved. However, when the binder phase is dissolved, the strength of the surface portion of the substrate decreases. Therefore, even if an uneven surface is formed, the adhesion between the substrate and the coating film may be deteriorated.

  In view of the above problems, the present invention provides a novel coated cemented carbide member with improved adhesion between the substrate and the hard film by making the surface of the substrate made of cemented carbide a specific uneven surface. The purpose is to provide.

  As described above, when the cemented carbide alloy phase is dissolved to form an uneven surface on the substrate, a problem arises in terms of strength and affects the adhesion. On the other hand, if the irregular surface is formed by leaving the cemented carbide alloy binder phase and eliminating the hard phase, the anchor effect can be exhibited without lowering the strength of the surface portion of the substrate. And when the present inventors disappear the hard phase of a cemented carbide and form an uneven surface on the surface of the substrate, the particle size of the metal carbide constituting the hard phase is close contact between the substrate and the hard film. It has been found that it greatly affects sex. Further, the binder phase has poor adhesion with the hard film. However, by leaving the binder phase and eliminating the hard phase, the area of the binder phase that is exposed increases. Therefore, it is important to improve the adhesion between the cemented carbide and the hard film by eliminating an appropriate amount of the hard phase according to the particle size of the metal carbide and suppressing the area of the binder phase to be exposed. I found a new thing.

That is, the coated cemented carbide member of the present invention includes a substrate made of a cemented carbide composed of a hard phase containing tungsten carbide (WC) and a binder phase containing a transition metal, and a hard film coated on the surface of the substrate. A coated cemented carbide member comprising:
The hard film essentially includes titanium (Ti) or chromium (Cr), and includes carbon (C) and / or nitrogen (N).
The surface of the base material coated with the hard film is a concavo-convex surface having a concave portion formed by the disappearance of the hard phase, the average particle diameter of WC is X [μm], and the maximum depth of the concave portion is Y [ μm], where the area ratio of the binder phase on the uneven surface is Z [%], the values of X, Y and Z are within the following first range and second range. .
First range:
1 ≦ X ≦ 6, 0 <Y ≦ −0.04X + 0.64,
Second range:
1 ≦ X ≦ 2, 0 <Z ≦ 71,
In 2 ≦ X ≦ 6, 0 <Z ≦ −5.25X + 81.5

  The coated cemented carbide member of the present invention has a concavo-convex surface by forming a recess by eliminating the hard phase from the surface of the substrate made of the cemented carbide. Therefore, since the binder phase that binds the WC particles constituting the hard phase remains, the strength of the surface portion of the substrate is maintained.

  At this time, the maximum depth of the recess is limited with respect to the average particle diameter of the WC constituting the hard phase, and the area ratio of the binder phase exposed to the surface and in contact with the hard film is limited by the formation of the recess. Thereby, the adhesiveness of a base material and a hard film improves rather than an untreated surface.

It is a schematic diagram which shows the cross section of the base material which has an uneven surface in the covering cemented carbide member of this invention. It is a schematic diagram which shows the cross section of the covering cemented carbide member of this invention. It is a schematic diagram for demonstrating electrolytic etching. It is a graph which shows the scratch peeling load with respect to the maximum etching depth (Y) of a base material about the covering cemented carbide member of an Example and a comparative example. It is a drawing substitute photograph which shows the result of having observed the surface of the base material which consists of cemented carbide A with the scanning electron microscope. It is a drawing substitute photograph which shows the result of having observed the surface of the base material which consists of cemented carbide B with the scanning electron microscope. 4 is a drawing-substituting photograph showing the result of observing the surface of a substrate made of cemented carbide D with a scanning electron microscope. 4 is a drawing-substituting photograph showing the result of observing the surface of a substrate made of cemented carbide E with a scanning electron microscope. 4 is a drawing-substituting photograph showing the result of observing the surface of a substrate made of cemented carbide F with a scanning electron microscope. It is a diagram which shows evaluation of the adhesiveness of a covering cemented carbide member with the relationship between the average particle diameter (X) of WC, and the maximum etching depth (Y). It is a diagram which shows evaluation of the adhesiveness of a covering cemented carbide member, with the relationship between the average particle diameter (X) of WC, and the area ratio (Z) of a binder phase.

  The best mode for carrying out the coated cemented carbide member of the present invention will be described below. In the present specification, the numerical range expressed as “N to M” without using an inequality sign includes N and M which are both ends of the numerical range.

  The coated cemented carbide member of the present invention includes a base material made of a cemented carbide and a hard film coated on the surface of the base material.

  The substrate is made of a cemented carbide, and the cemented carbide is composed of a hard phase containing tungsten carbide (WC) and a binder phase containing an iron group metal. The cemented carbide is a general cemented carbide obtained by sintering a raw material powder obtained by mixing a metal carbide powder (hard phase) such as WC and a metal powder (binding phase). A preferable mass ratio of the hard phase and the binder phase is hard phase: bond phase = 80 to 99:20 to 1 and further 90 to 99:10 to 1. If the mass ratio of the hard phase and the binder phase is within the above range, a desired uneven surface can be easily formed, and the anchor effect can be sufficiently obtained. Moreover, the cemented carbide in which the mass ratio of the hard phase and the binder phase is within the above range is excellent in mechanical properties.

The hard phase is mainly composed of WC. The content of WC is 70 to 100% by mass, 90 to 100% by mass, and further 95 to 100% by mass when the entire hard phase is 100% by mass. The hard phase may contain a metal carbide other than WC in a small amount. For example, titanium carbide (TiC), tantalum carbide (TaC), niobium carbide (NbC), vanadium carbide (VC), chromium carbide (Cr ₃ C). ₂ ) One or more of the above. Moreover, the average particle diameter of WC which comprises a hard phase is good in it being 1 to 6 micrometers. What is necessary is just to select suitably according to the use purpose of a covering cemented carbide member, if it is a cemented carbide containing WC of the average particle diameter of this range. In addition, the average particle diameter of WC corresponds with the average particle diameter of the WC particle contained in the raw material powder used for manufacture of a cemented carbide. Even when a commercially available cemented carbide is used as a base material, the average particle diameter of WC is a binary image obtained by observing a predetermined range with an optical microscope, a scanning electron microscope (SEM), or the like. Is an arithmetic average value of values obtained by measuring the maximum diameter (maximum length) of a plurality of WC particles, and the average particle diameter obtained by the measurement substantially matches the nominal average particle diameter .

  The binder phase is mainly composed of a transition metal such as chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), and molybdenum (Mo). In particular, Ni, Cr and Co are preferable. At least one of these may be contained in the binder phase, but it is more preferable that Co is mainly contained. The Co content is preferably 80 to 100% by mass, and more preferably 90 to 100% by mass, based on 100% by mass of the entire binder phase. Further, if the entire cemented carbide is 100% by mass, the Co content is preferably 1 to 20% by mass, and more preferably 1 to 10% by mass.

  In addition, the area ratio of the binder phase before the uneven surface on the surface of the base material (that is, the cemented carbide) is 0.7 to 1.5% from the mass ratio of the hard phase and the binder phase. It is preferable that it is 0.7 to 4.0%. That is, the area ratio of the binder phase after the uneven surface is formed exceeds 0.7%. The “area ratio of the binder phase” is the area ratio of the binder phase existing in a plane when the surface of the substrate is observed perpendicularly to the surface. For example, a grayscale image obtained by observing a predetermined range with an optical microscope, SEM, etc. is binarized to separate it into a target area (bonded phase) and a background (hard phase), and the target area for the entire area The area ratio of the binder phase can be obtained by calculating the area.

The hard film coated on the surface of the substrate is not particularly limited in its composition, film thickness, etc. as long as it is made of a compound containing Ti and Cr as essential and containing C and / or N. What is necessary is just to select suitably according to the intended purpose of the covering cemented carbide member. For example, a titanium compound having a composition in which part of Ti or Cr is substituted with another element may be used. Examples of other elements include aluminum (Al). Specific examples include a TiCN film, a TiC film, a TiN film, a TiAlN film, a CrN film, and a Cr ₃ C ₂ film. Of these, a titanium-based compound film containing Ti such as a TiCN film is particularly effective. Furthermore, in view of the evaluation results of the adhesion of a coated cemented carbide member having a TiCN film, which will be described later, if the surface properties of the substrate are the same, similar results can be obtained even with a Cr-based compound film. Predictable. Further, the film thickness is preferably 0.5 μm or more, and more preferably 1 to 5 μm, as long as the surface of the substrate is not exposed. Such a hard film can be formed by a known CVD method or PVD method such as a plasma CVD method, an ion plating method, or a sputtering method.

The surface of the base material coated with the hard film is an uneven surface having a recess formed by disappearance of the hard phase. The recess preferably has only the hard phase disappeared. FIG. 1 is a schematic view showing a cross section of a substrate having an uneven surface. The base material 10 having an uneven surface is made of a cemented carbide composed of a binder phase 11 and a hard phase composed of WC particles 12. By removing the WC particles 12 on the surface of the base material 10 to form the concave portion 12 ⁻ , the surface of the base material 10 becomes an uneven surface 10 f. FIG. 2 is a schematic view showing a cross section of the coated cemented carbide member of the present invention. By coating the hard film 2 on the uneven surface 10f, the hard film 2 is recess 12 ^- are deposited by depositing to the inside of, resulting in the anchor effect.

The uneven surface has values of X, Y, and Z when the average particle diameter of WC is X [μm], the maximum depth of the recess is Y [μm], and the area ratio of the binder phase on the uneven surface is Z [%]. Is in the following first range and in the second range.
First range:
1 ≦ X ≦ 6, 0 <Y ≦ −0.04X + 0.64,
Second range:
1 ≦ X ≦ 2, 0 <Z ≦ 71,
In 2 ≦ X ≦ 6, 0 <Z ≦ −5.25X + 81.5

  A preferred first range is that in FIG. 10 where the average particle diameter X of WC is the horizontal axis and the maximum depth Y of the recess is the vertical axis, (X, Y) is a point (1, 0), b point (1, 0.6), the inside of the region indicated by the oblique line surrounded by the c point (6, 0.4) and the d point (6, 0.4) and on the line. However, the line a-d is not included. A preferred second range is that (X, Z) is a p point (1, 0), a q point (X) in FIG. 11 where the horizontal axis is the average particle diameter X of WC and the vertical axis is the area ratio Z of the binder phase. 1, 71), r point (2, 71), and s point (6, 50). However, the line pt is not included.

Here, the “maximum depth of the concave portion” is the depth of the concave portion in the vertical direction from the outermost surface of the substrate among the concave portions constituting the uneven surface, and the position of the outermost surface of the substrate is the binding phase. It corresponds to the position of the tip. Usually, since the concave portion is formed by etching the surface of the substrate, the depth of the concave portion is an etching depth (D _{e in} FIG. 1). For example, since cemented carbide is a sintered body, WC particles may be shallowly buried in the surface depending on the location. If such a portion is etched to form a recess, even if etching is performed from the surface to a predetermined depth, the WC particles are completely eluted before reaching the predetermined depth, and the binder phase is exposed, and the depth is further increased. The recess is not formed. Etching depth of the recess is _{D e} in FIG. 1 ^- is represented _by, ^D e - a _{<D e.} Therefore, in this specification, the “maximum depth of the recess” is defined. The maximum depth of the recess can be measured by a surface roughness meter, an atomic force microscope (AFM), or the like. In addition, it is desirable that 50% or more, more than 80% or more of the plurality of recesses constituting the uneven surface reach the maximum depth. Further, “average particle diameter of WC” and “area ratio of binder phase” are as described above.

  As described above, the coated cemented carbide member of the present invention has a feature that the shape of the rough surface that is optimal for exhibiting the anchor effect is influenced by the average particle size of WC constituting most of the hard phase. doing. The effect of improving the adhesion between the substrate and the hard film in the present invention is manifested in a substrate made of a cemented carbide having a WC average particle size (X) of 1 μm or more, and 1 ≦ X ≦ 6, 1 ≦ X. ≦ 3, or even 1 ≦ X ≦ 2, is remarkable.

  If even a slight depression is formed on the surface of the base material, an anchor effect is obtained, and the adhesion is improved as compared with an untreated base material having no uneven surface. Therefore, the value of Y is 0 <Y (Y = 0 Is preferably untreated), preferably 0.05 ≦ Y, more preferably 0.1 ≦ Y. On the other hand, if the maximum depth of the recess is too deep, the adhesiveness is lowered, and the influence is more remarkable as the average particle diameter of WC is larger. If 1 ≦ X ≦ 6 and 0 <Y ≦ −0.04X + 0.64, the adhesion is improved as compared with the untreated substrate. In other words, when 1 ≦ X ≦ 6, even if the average particle diameter of WC is large, if the maximum depth of the recess is in the range of 0 <Y ≦ −0.04X + 0.64, the adhesion is greater than that of the untreated substrate. Improves. Further, when 1 ≦ X ≦ 2, Y ≦ 0.5, further Y ≦ 0.4, and Y ≦ 0.4 regardless of the average particle diameter of WC, so that the adhesiveness compared with the untreated substrate is improved. Is greatly improved.

  Further, when the concave portion disappears, the area of the binder phase increases, but as already described in detail, the adhesion decreases when the area ratio of the binder phase increases. If 1 ≦ X ≦ 2 and 0 <Z ≦ 71, 2 ≦ X ≦ 6 and 0 <Z ≦ −5.25X + 81.5, the adhesion is improved. When the average particle diameter of WC is small, the effect of improving adhesion is easily obtained even if the area ratio of the binder phase is increased. However, when the area ratio of the binder phase exceeds 71%, the adhesion deteriorates. That is, in 1 ≦ X ≦ 2, a decrease in adhesion can be suppressed if the area ratio of the binder phase is in the range of 0 <Z ≦ 71 and further 0 <Z ≦ 70. On the other hand, if the average particle size (X) of WC exceeds 2, it is difficult to obtain adhesion unless the area ratio of the binder phase is suppressed. In 2 ≦ X ≦ 6, if 0 <Z ≦ −5.25X + 81.5, and further 0 <Z ≦ −5.4X + 80.8, a decrease in adhesion can be suppressed. If it is the range of 1 <= X <= 6, the adhesive improvement effect is maintained by restraining to Z <= 50. In addition, although adhesiveness improves, so that the area ratio Z of a binder phase is small, if the minimum of Z is prescribed | regulated, it is a value exceeding the area ratio of the binder phase of the base material before a process. The area ratio of the binder phase of the base material before treatment is a value corresponding to the ratio of the binder phase contained in the cemented carbide. That is, 0.7 <Z is preferable, more preferably 5 ≦ Z, and further preferably 9 ≦ Z.

  The uneven surface is formed by eliminating the hard phase existing on the surface of the base material by a predetermined depth. An example of the method for forming the uneven surface is anodic electrolytic etching using an alkaline solution. By performing anodic electrolytic etching in an alkaline solution, the binder phase is not dissolved, and only the hard phase, that is, WC, can be dissolved. Electrolytic etching can be performed by a known method. Specifically, the base material is an anode, and the anode and the cathode are immersed in an alkaline solution to perform electrolytic treatment.

  The cathode may be a metal material other than an amphoteric metal that is corroded by an alkaline solution, and a general metal material such as iron, stainless steel, nickel, or copper may be used. There is no particular limitation on the shape of the cathode, but a shape facing the substrate at almost equal intervals is desirable because current can easily flow uniformly. For example, if the base material has a columnar shape, a stainless steel container may be used as an electrolytic cell and a cathode.

  The alkaline solution may be an aqueous solution or a non-aqueous solution. Specific examples of the alkali include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate and the like. The alkali concentration is preferably pH 11 to pH 14.5, more preferably pH 12 to pH 14. Below pH 11, the etching rate is too slow and not efficient. If the pH exceeds 14.5, the etching rate is not increased, and the etching depth is likely to be nonuniform, which is not desirable.

The electrolytic treatment conditions are adjusted according to the maximum depth (etching depth) of the recess. For example, the total amount of electricity to be energized may be adjusted in the range of 0.05 coulomb / cm ^{2 to} 5 coulomb / cm ² and the current density in the range of 1 to 50 mA / cm ² . In addition, the processing time varies depending on the etching depth, that is, the amount of electricity and the current density, so it cannot be generally stated. However, as a guideline, the etching rate is selected to be 0.005 to 0.1 μm / min. Is good.

Further, the surface of the substrate to be electrolytically etched is preferably polished in advance so as to have a surface roughness corresponding to the purpose of use. Specifically, mirror finishing with a ten-point average roughness Rz _{jis of} about 0.1 μm as defined in JIS is desirable. In addition, after the electrolytic etching is finished, the base material is washed with an organic solvent or the like and then used for forming a hard film.

  The coated cemented carbide member of the present invention is excellent in adhesion between the base material and the hard film, and is therefore suitable for various members made of cemented carbide requiring a protective film on the surface. Specific applications of the coated cemented carbide member of the present invention include molds and tools. In particular, if it is a coated cemented carbide member exhibiting high peel strength, it can be expected to be used for tools and dies for the purpose of reducing the environmental load.

  As mentioned above, although embodiment of the covering cemented carbide alloy member of this invention was described, this invention is not limited to the said embodiment. The present invention can be implemented in various forms without departing from the gist of the present invention, with modifications and improvements that can be made by those skilled in the art.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples of the coated cemented carbide member of the present invention.

[Preparation of sample]
Cemented carbides A to F shown in Table 1 were prepared. These cemented carbides are WC-Co cemented carbides, A is H1 manufactured by Sumitomo Electric Hardmetal Co., Ltd., B is D3 manufactured by Daidget Industries, Ltd., and C is KH05 manufactured by Sumitomo Electric Hardmetal Co., Ltd. , D, E, and F were manufactured by Sun Alloy Co., Ltd., and REA65, VA60, and RL89 were used in this order. In addition, the average particle diameter, Co content, and hardness of WC shown in Table 1 are nominal values. As a base material, a plurality of plate materials (40 mm × 10 mm × thickness 5 mm) made of these cemented carbides were produced.

The surface of these base materials was made into a mirror surface of Ra 2.0 nm or less with a centerline surface roughness specified in JIS, and the other surface was covered with a masking tape, leaving only one surface of 40 mm × 10 mm. This was degreased and washed, followed by electrolytic etching. The electrolytic etching was performed using an apparatus 30 shown in FIG. The apparatus 30 includes a container 31 that is an electrolytic cell for holding an electrolytic solution 32, a cathode 33 as a counter electrode, and a DC power source 34 that applies a current between the cathode 33 and the base material 10 ′. The electrolyte solution 32 was a 1N sodium hydroxide (pH 14) aqueous solution. As the cathode 33, a stainless steel plate material of 40 mm × 10 mm × thickness 1 mm was used. Then, electrolytic etching was performed on the substrate surface at room temperature for ² to 15 minutes with a current density of 3 to 15 mA / cm ² . In the electrolytic etching, the maximum etching depth is adjusted by changing the current value and the etching time within the above range, and the surface of each substrate is uneven with the maximum etching depth (target value) shown in Table 2. The surface. Each substrate after electrolytic etching was subjected to ultrasonic cleaning with acetone after washing with water and drying. Next, a hard film was coated on the surface of the substrate having an uneven surface. As the hard film, a TiCN film having a thickness of 2 to 3 μm was formed by the PVD method.

  Each sample shown in Table 2 was produced by the above procedure. Samples A0 to F0 are coated hard metal members of comparative examples in which a TiCN film is formed on the surface of an untreated base material that has not been subjected to electrolytic etching and has been mirror-finished. The adhesion of each sample was evaluated based on whether or not the adhesion was improved or decreased based on a sample using the same kind of cemented carbide among these samples A0 to H0.

[Evaluation]
[Measurement of maximum etching depth]
The surface roughness in the range of 10 μm × 10 μm of the surface of the substrate was measured by AFM. The measurement result of each sample was equivalent to the target value of the maximum etching depth shown in Table 2. Therefore, in FIG. 4 to FIG. 11 used for later explanation, the target value shown in Table 2 is used as the value of the maximum etching depth Y.

[Evaluation of adhesion]
The peel strength (adhesion strength) of the TiCN film was measured by the Rockwell test and the scratch test. Here, from the standpoint of practicality and stability of the evaluation method, the load (peeling load) when the TiCN film was peeled in the observation using an optical microscope was defined as the adhesion force.

  For the Rockwell test, the adhesion was evaluated from the peeling form of the TiCN film around the indentation on the C scale. In the scratch test, a conical diamond (indenter diameter: 0.2 mm) was used, and the table speed was 10 mm / min and the load increasing speed was 100 N / min. FIG. 4 shows the peel load of each sample obtained from the scratch test. Further, in the column of “Adhesion” in Table 2, the evaluation results of the adhesion evaluated based on the samples A0 to H0 as described above are shown. A sample with improved peel strength over the reference sample was marked with ◯, and a sample with lowered peel strength was marked with x.

[Calculation of binder phase area ratio]
The surface of the base material immediately before forming the TiCN film was observed by SEM. The SEM observation was performed by adjusting the orientation of the substrate so that the focused electron beam was perpendicular to the surface of the substrate. Some of the observation results are shown in FIGS. FIG. 5 shows the surface observation results of the base material made of cemented carbide A. From the left, the sample A0 (untreated), the sample A1 (Y = 0.1: the unit is μm), and the sample A2 (Y = 0. 2) SEM observation results of sample A3 (Y = 0.4), which are binary data images obtained by binarizing the secondary electron image, the reflected electron image, and the reflected electron image, respectively, in order from the top. 6 to 9 are the results of surface observation of the base material using different types of cemented carbide, FIG. 6 is cemented carbide B, FIG. 7 is cemented carbide D, and FIG. 8 is cemented carbide E. FIG. 9 shows a cemented carbide F. For the area ratio of the binder phase, the area of the white portion relative to the entire area of the binarized data image was calculated using image processing software. All the calculated results are shown in Table 2.

  Based on the measurement results shown in Table 2, the average particle diameter (X) and the maximum etching depth (Y) of WC for each sample are shown in FIG. 10, and the average particle diameter (X) of WC and the area ratio of the binder phase for each sample. (Z) is shown in FIG. In FIGS. 10 and 11, as in Table 2, samples with improved peel strength are indicated with “◯” and samples with reduced peel strength based on samples A0 to H0 in which a TiCN film is formed on an untreated substrate. Is indicated by ×.

  In both FIG. 10 and FIG. 11, the sample (indicated by ◯) whose adhesion was improved as compared with the untreated was within the range indicated by the oblique lines. In particular, when the average particle diameter (X) of WC is 1 ≦ X ≦ 3, and further 1 ≦ X ≦ 2, the values of Y and Z are within the range shown by the oblique lines in FIG. 10 and FIG. As a result, the adhesion strength (peeling load) was extremely high (see FIG. 4).

  Further, when cemented carbides A to E, particularly A to C were used as the base material, the improvement in adhesion was remarkable. Although not shown in FIG. 4, when the maximum etching depth with respect to the substrate made of the cemented carbide B is 0.6 μm or more, it tends to decrease to the same degree as the adhesion of the sample B0.

10: substrate 10f: uneven surface 11: bonding phase 12: WC particles (hard phase) 12 ^-: recess 2: hard film

Claims (6)

A coated cemented carbide member comprising a substrate made of a cemented carbide comprising a hard phase containing tungsten carbide (WC) and a binder phase containing a transition metal, and a hard film coated on the surface of the substrate. ,
The hard film essentially includes titanium (Ti) or chromium (Cr), and includes carbon (C) and / or nitrogen (N).
The surface of the base material coated with the hard film is a concavo-convex surface having a concave portion formed by the disappearance of the hard phase, the average particle diameter of WC is X [μm], and the maximum depth of the concave portion is Y [ μm], where the area ratio of the binder phase on the uneven surface is Z [%], the values of X, Y and Z are within the following first range and second range. Coated cemented carbide member.
First range:
1 ≦ X ≦ 6, 0 <Y ≦ −0.04X + 0.64,
Second range:
1 ≦ X ≦ 2, 0 <Z ≦ 71,
In 2 ≦ X ≦ 6, 0 <Z ≦ −5.25X + 81.5   2. The coated cemented carbide member according to claim 1, wherein the second range is 0 <Z ≦ 70 in 1 ≦ X ≦ 2 and 0 <Z ≦ −5.4X + 80.8 in 2 ≦ X ≦ 6.   The coated cemented carbide member according to claim 1, wherein Y is 0.1 ≦ Y.   The coated cemented carbide member according to claim 1, wherein Z is 0.7 <Z.   The coated cemented carbide member according to any one of claims 1 to 4, wherein the binder phase contains cobalt (Co).   The coated hard metal alloy according to any one of claims 1 to 5, wherein the hard film is a titanium compound film containing titanium (Ti) as an essential component and containing carbon (C) and / or nitrogen (N).