JP5037931B2 - Surface coating tool - Google Patents

Description

  The present invention relates to a surface-coated tool formed by forming a coating layer on the surface of a substrate.

  At present, surface-coated tools that require wear resistance, slidability, and fracture resistance, such as cutting tools, wear-resistant members, and sliding members, have a variety of surfaces on hard materials such as WC-based cemented carbide and TiCN-based cermets. A technique for improving the wear resistance, slidability, and fracture resistance by forming a coating layer is used.

  As the coating layer, a TiCN layer or a TiAlN layer is generally widely used, but various coating layers are being developed for the purpose of improving higher wear resistance and fracture resistance.

For example, in Patent Document 1, the deposition conditions and wear resistance of the work material are reduced by adjusting the film formation conditions to reduce coarse particles having a size larger than the film thickness present in the TiAlN hard coating. It is disclosed that the performance is improved. Patent Document 2 describes a composite hard film in which a TiAlN composite nitride dispersed particle having a composition different from that of the film base is dispersed and strengthened in the TiAlN-based hard film, and the base and the dispersed particle have the same kind of crystal structure. It is disclosed that the synergistic effect of characteristic improvement can be exhibited and the cutting performance is improved. Furthermore, in Patent Document 3, a coating layer is formed by forming a TiAlN-based hard coating layer and then performing a thermal oxidation treatment to form a structure in which Ti oxide, Al oxide, and the like are dispersed and distributed in a TiAlN-based substrate. It is disclosed that the wear resistance of the toner is improved.
JP 2002-346812 A JP 2002-129306 A Japanese Patent Laid-Open No. 10-251831

  However, the coating layer with reduced coarse particles as in the above-mentioned Patent Document 1 has high smoothness on the surface of the coating layer, and has the effect of suppressing welding of the work material and improving wear resistance, but the fracture resistance of the coating layer. As a result, a large residual stress was generated in the coating layer, and the coating layer itself could be self-destructed. In addition, as in Patent Document 2 and Patent Document 3, in the coating layer in which the inside of the coating layer is simply dispersion strengthened with Ti-based or Al-based dispersed particles that are the main component of the coating layer, the fracture resistance of the coating layer Although the improvement was not sufficient, the residual stress was still high and it was necessary to reduce the residual stress.

  Therefore, the surface-coated tool of the present invention is for solving the above-mentioned problems, and the object thereof is to provide a surface-coated tool having high wear resistance and high fracture resistance.

Surface coated tool of the present _{invention, Ti 1-a-b -c} -d Al a M b W c Si d (C x N 1-x) ( where the metal element M is Nb, Mo, Ta, Hf, Y At least one selected from the group consisting of 0.4 5 ≦ a ≦ 0.5 5, 0.0 1 ≦ b ≦ 0.1, 0.01 ≦ c ≦ 0.1, 0.01 ≦ d ≦ 0. 0 5,0 a ≦ x ≦ 1.) consisting of the coating layer is coated, a plurality of projections on the surface of the coating layer is dispersed, the protrusion portion, the containing Ti as a main component and Al 1 projection part and the 2nd projection part which has any one of metal element M , W, or Si as a main component, It is characterized by the above-mentioned.

Moreover , in the said structure, in the diameter distribution of the said protrusion part , it has two peak tops, the peak top of the fine protrusion part which is a smaller one exists in the range of 0.1-0.8 micrometer , and the larger one the peak top of a coarse projections is desirably in the range near Rukoto of 1 to 5 [mu] m.

  Moreover, in the said structure, it is desirable for the existence ratio of the said projection part in the surface of the said coating layer to be 1-30 area%.

  Furthermore, in the above-described configuration, it is desirable that the first protrusions have a ratio of 30 to 100 and the second protrusions have a ratio of 3 to 20 in a 25 μm × 18 μm region on the surface of the coating layer. .

Surface coated tool of the present _{invention, Ti 1-a-b -c} -d Al a M b W c Si d (C x N 1-x) ( where the metal element M, Nb, Mo, Ta, Hf, One or more selected from Y , 0.4 5 ≦ a ≦ 0.5 5, 0.0 1 ≦ b ≦ 0.1, 0.01 ≦ c ≦ 0.1, 0.01 ≦ d ≦ 0 .0 5,0 is ≦ x ≦ 1.) consisting of the coating layer is coated, a plurality of projections on the surface of the coating layer is dispersed, the protrusion portion is mainly composed of Ti and Al The effect of reducing the residual stress generated in the coating layer is high by comprising the one protrusion and the second protrusion mainly composed of one of the metal elements M 2 , W, and Si . As a result, the coating layer has good chipping resistance without self-destruction, and the coating layer can be made thicker.

Moreover , in the said structure, in the diameter distribution of the said protrusion part , it has two peak tops, the peak top of the fine protrusion part which is a smaller one exists in the range of 0.1-0.8 micrometer , and the larger one by some coarse range near Rukoto peak top of 1~5μm protrusions, it is possible to exhibit the effect of reducing the residual stress in a larger coating layer.

  Moreover, in the said structure, while the ratio of the said protrusion part in the surface of the said coating layer is 1-30 area%, while being able to improve the fracture resistance of a coating layer, the abrasion resistance of a coating layer is maintained. This is desirable because it can be done.

  Furthermore, in the above configuration, in the region of 25 μm × 18 μm on the surface of the covering layer, the first protrusions are present in a ratio of 30 to 100, and the second protrusions are present in a ratio of 3 to 20, This is desirable in that the fracture resistance of the coating layer can be increased and the wear resistance of the coating layer can be maintained.

  An example of a surface-coated cutting tool that is a preferred example of the surface-coated tool of the present invention will be described.

Surface-coated cutting tool of the present invention (hereinafter, simply referred to as tool) is without intersecting ridgeline between the rake face and the flank shape is cutting edge, and a configuration in which the formation of the coating layer on the surface of the substrate ing. Coating _{layer, Ti 1-a-b -c} -d Al a M b W c Si d (C x N 1-x) ( where the metal element M is selected Nb, Mo, Ta, Hf, from Y 1 type or more, 0.4 5 ≦ a ≦ 0.5 5, 0.0 1 ≦ b ≦ 0.1, 0.01 ≦ c ≦ 0.1, 0.01 ≦ d ≦ 0.05, is 0 ≦ x ≦ 1.) Ru Tona.

According to the present invention, a plurality of protrusions are dispersed on the surface of the coating layer, and the protrusions include a first protrusion mainly containing Ti and Al, and a metal element M as a main ingredient. By providing at least two types of the second projecting portion, the residual stress generated in the coating layer with a small abundance can be effectively reduced. Here, the first protrusion may contain a metal element M having a content that is the same as or less than the content of the metal element M in the entire coating layer, and the second protrusion These may contain Ti and Al elements with a content that is the same as or less than the respective contents of Ti and Al elements in the entire coating layer.

  With the above configuration, residual stress generated inside the coating layer can be reduced, and stable film formation is possible without self-destruction even when the coating layer thickness is increased. Improves. Specifically, even if the coating layer is thick, the coating layer is difficult to chip, and even if the coating layer thickness is 0.5 to 6 μm, it is sufficient to prevent the coating layer from peeling or chipping. High wear resistance can be maintained.

Then, the set formed of the coating _{layer, Ti 1-a-b-} c-d Al a M b W c Si d (C x N 1-x) ( however, M is Nb, Mo, Ta, Hf, from Y One or more selected, 0.45 ≦ a ≦ 0.55, 0.01 ≦ b ≦ 0.1, 0.01 ≦ c ≦ 0.1, 0.01 ≦ d ≦ 0.05, 0 ≦ x ≦ 1) . By satisfying this composition, the oxidation start temperature is high, the oxidation resistance is high, the wear resistance at the time of cutting is improved, the chipping that is likely to occur at the cutting edge tip can be suppressed, and the chipping resistance is high. .

  In addition, C and N, which are non-metallic components of the coating layer, are excellent in hardness and toughness required for cutting tools and suppress excessive generation of droplets (coarse particles) generated on the surface of the coating layer. Therefore, a particularly desirable range of x (N content) is 0 ≦ x ≦ 0.5. Here, according to the present invention, the composition of the coating layer can be measured by energy dispersive X-ray analysis (EDX) or X-ray photoelectron spectroscopy (XPS).

Here, in the above configuration, the diameter distribution of the protrusion has two peak tops, and the peak top of the fine protrusion which is the smaller is in the range of 0.1 to 0.8 μm, which is large. the range near Rukoto of the is coarse projections peak top. 1 to 5 [mu] m towards reduces the residual stress of the coating layer, it can exhibit a greater effect.

  In addition, it is desirable that the ratio of the protrusions on the surface of the coating layer is 1 to 30% by area because the fracture resistance of the coating layer can be improved and the wear resistance of the coating layer can be maintained. .

  Furthermore, in a 25 μm × 18 μm region on the surface of the coating layer, the presence of 30 to 100 first protrusions and 3 to 20 second protrusions indicates that the resistance of the coating layer is high. It is desirable in that the chipping property can be improved and the wear resistance of the coating layer can be maintained.

The covering layer is preferably composed mainly of columnar crystals grown in a direction perpendicular to the surface of the substrate in order to increase the hardness and toughness of the covering layer. And the 1st protrusion part has the component of the coating layer inside the coating layer that the droplet (coarse particle) which has Ti and Al scattered from the target at the time of film deposition adheres to the surface of the coating layer After the droplets (coarse particles) consisting of any of the above are attached, columnar crystals of the coating layer component grow from the coarse particles as a starting point, and the columnar shape (fan shape) protrudes outward on the surface of the coating layer above the coarse particles Presumed to be composed of crystals. On the other hand, it is estimated that the second protrusion is formed by droplets of the metal element M scattered from the target during film formation. In many cases, droplets of the metal element M are also present inside the coating layer.

  In the above configuration, the average width of the columnar crystals is preferably 0.05 to 0.5 μm in order to increase the hardness and strength of the coating layer and improve the wear resistance. Moreover, it is desirable that the average particle diameter of the coarse particles is 0.05 to 0.2 μm in that the toughness of the coating layer can be increased.

  As the substrate, tungsten carbide, a cemented carbide or cermet composed of a hard phase mainly composed of titanium carbonitride and a binder phase mainly composed of an iron group metal such as cobalt or nickel, silicon nitride, , Hard materials such as ceramics mainly composed of aluminum oxide, a hard phase made of polycrystalline diamond or cubic boron nitride, and a binder phase such as ceramics or iron group metal under an ultra-high pressure. Are preferably used. Steel and high-speed steel can also be used. Steel and high speed steel can also be used.

(Production method)
Next, the manufacturing method of the surface coating cutting tool which is an example of the surface coating tool of this invention is demonstrated.

First, a tool-shaped substrate is produced using a conventionally known method. Next, a coating layer is formed on the surface of the substrate. As the film formation method of coating layer, Ru using an ion plating method of physical vapor deposition (PVD) method. It described in detail an example of a film-forming method.

The data Getto, a first target composed mainly of Ti and Al, using two targets of the second target containing a metal element M, thus forming a film of the coating layer to the ion plating Thus, a coating layer in which two kinds of protrusions, the first protrusion and the second protrusion, are dispersed in the columnar crystal described above can be manufactured. As for the conditions for forming the coating layer, flow rate of argon gas to nitrogen is 1: 9 to 4: 6 ratio of nitrogen (N ₂₎ gas and argon (Ar) formed to be Kutsugaeso using a mixed gas of the gas Although film, the first target is the main target for forming the coating layer, using the second target you containing a metal element M, a DC power source to the first target, the pulse power source to the second target By applying each, the surface covering tool which comprises the coating layer of the present invention mentioned above is obtained.

Incidentally, in forming the upper Symbol coating layer, a bias voltage 30~200V in order to increase the adhesion between the substrate together by controlling the crystal structure and orientation of the coating layer can be produced high hardness coating layer It is preferable to apply.

10% by mass of metallic cobalt (Co) powder and 1% by mass of vanadium carbide (VC) powder and chromium carbide (Cr ₃ C ₂ ) powder with respect to tungsten carbide (WC) powder having an average particle size of 0.5 μm Were added, mixed, molded into an end mill shape and fired. And after passing through the grinding process, the surface was washed in the order of alkali, acid, and distilled water to produce a 4-flute end mill substrate having an outer diameter of 16 mm.

The substrate is set in various types of apparatuses equipped with the targets shown in Table 1 and heated to 550 ° C., and a bias voltage shown in Table 1 is applied to each target to form a coating layer under the conditions shown in Table 1. Filmed. The film forming conditions are a mixed gas of nitrogen gas and argon gas in an atmosphere with a total pressure of 4 Pa, the arc current of the first target is 150 A DC, and the pulse current of the second target is such that the coating layer has a predetermined composition. The composition of the coating layer was controlled in the range of 80 to 150A. The bias voltage was 50V and the heating temperature was 550 ° C.

The surface of the coating layer of the obtained end mill was observed with a scanning electron microscope (VE8800) manufactured by Keyence Corporation at a magnification of 500 times (25 μm × 18 μm region), and an EDAX analyzer (AMETEK EDAX) attached to the apparatus was attached. -VE9800) was used to quantitatively analyze the composition of the coating layer and the protrusions by the ZAF method, which is a type of energy dispersive X-ray spectroscopy (EDX) method, at an acceleration voltage of 15 kV. For elements that could not be measured by this method, an X-ray photoelectron spectrometer (Quantum2000) manufactured by PHI was used, and the X-ray source was monochrome AlK (200 μm,
35 W, 15 kV) was irradiated to a measurement region of about 200 μm, and measurement was performed. The composition of the protrusions was analyzed and classified into a first protrusion and a second protrusion, and the number of the protrusions was counted. The results are shown in Table 2.

  Further, the diameters of the protrusions on the surface of the coating layer were measured, and the distribution of the diameters was measured. In the case where the diameter distribution has two peaks, the peak top diameter is described in Table 2 as a fine protrusion and a larger diameter as a coarse protrusion.

  Next, a cutting test was performed under the following cutting conditions using the obtained hard coating-coated end mill. The results are shown in Table 3.

Cutting method: Down cut Work material: SCM440
Cutting speed: 75 m / min
Feeding: 0.04 mm / blade Cutting: cutting depth d = 18 mm × horizontal cutting w = 1.6 mm
Cutting condition: wet Evaluation method: Presence / absence of chipping after cutting for 90 minutes, flank wear width measurement

From Tables 1-3, No. in which no protrusion exists . In No. 12, chipping occurred on the cutting edge, leading to a loss early. In addition, No. 1 in which one type of protrusion is dispersedly present . In No. 11, chipping occurred on the cutting edge, leading to defects early. Further, although two protrusions that exist dispersed, the specimen protruding portion is mainly composed of both Ti No. No. 9 chipping occurred.

On the other hand, two types of protrusions are dispersed, and this protrusion includes a first protrusion mainly composed of Ti and Al, and a second protrusion mainly composed of the metal element M. Sample No. In 1 to 8, 10 and 13, the fracture resistance was improved and the cutting performance was excellent. Then, the coating layer _{is, Ti 1-a-b-} c-d Al a M b W c Si d (C x N 1-x) ( however, M is selected Nb, Mo, Ta, Hf, from Y 1 0.45 ≦ a ≦ 0.55, 0.01 ≦ b ≦ 0.1, 0.01 ≦ c ≦ 0.1, 0.01 ≦ d ≦ 0.05, 0 ≦ x ≦ 1 A first projection portion whose main component is Ti and Al, and a second projection portion whose main component is one of the metal elements M, W, or Si. Sample No. consisting of 8 and 13 were found to be more excellent in fracture resistance and cutting performance.

Claims (4)

On the surface of the _{substrate, Ti 1-a-b -c} -d Al a M b W c Si d (C x N 1-x) ( where the metal element M is chosen Nb, Mo, Ta, Hf, from Y 0.4 5 ≦ a ≦ 0.5 5, 0.0 1 ≦ b ≦ 0.1, 0.01 ≦ c ≦ 0.1, 0.01 ≦ d ≦ 0.0 5 a 0 ≦ x ≦ 1.) consisting of the coating layer is coated, a plurality of projections on the surface of the coating layer is dispersed, the protrusion portion, the first composed mainly of Ti and Al A surface-coated tool comprising a projecting portion and a second projecting portion mainly comprising any one of the metal elements M 1 , W, and Si .   In the diameter distribution of the protrusion, the peak has two peak tops, the peak top of the fine protrusion which is the smaller is in the range of 0.1 to 0.8 μm, and the peak of the larger protrusion which is the larger 2. The surface-coated tool according to claim 1, wherein the top is in the range of 1 to 5 [mu] m.   The surface-coated tool according to claim 1 or 2, wherein a ratio of the protrusions on the surface of the coating layer is 1 to 30% by area.   The area of 25 μm × 18 μm on the surface of the covering layer has 30 to 100 first protrusions and 3 to 20 second protrusions, respectively. 4. The surface-coated tool according to any one of 3.