JP2009034781A - Surface-coated cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-coated cutting tool which improves its wear-resistance. <P>SOLUTION: The surface-coated cutting tool has a base material, and a coating layer formed on the base material. The coating layer includes one or more of chemical vapor deposition layers formed by a chemical vapor deposition method, and one or more of physical vapor deposition layers formed by a physical vapor deposition method on the chemical vapor deposition layer. The physical vapor deposition layer includes a supper-multilayer structural layer or a modulated structural layer, and the super-multilayer structural layer has a structure wherein two kinds or more of unit layers formed by a specific compound are repetitively laminated at respective thickness of 0.2-20 nanometers. The modulated structural layer is constituted by a specific compound, and has a structure wherein a composition or a composition ratio of the compound is changed at a cycle of 0.2-40 nanometers in its thickness direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  A base material constituting a cutting tool has been coated with various coating layers for the purpose of further improving various properties such as wear resistance and toughness. The chemical vapor deposition method known as a method for forming such a coating layer is known to cause diffusion of constituent components between the substrate and the coating layer during the formation of the coating layer. It has the advantage that the adhesion strength of can be increased. However, since such chemical vapor deposition method becomes extremely high at the time of forming the coating layer, the thermal expansion coefficient of the substrate and the thermal expansion coefficient of the coating layer are different when cooled to room temperature after the formation of the coating layer. This causes tensile residual stress in the coating layer. For this reason, when a crack occurs in the coating layer during the cutting process, there is a problem that propagation of the crack is promoted to cause a defect.

  In order to solve this problem, attempts have been made to release tensile residual stress by subjecting the coating layer formed by chemical vapor deposition to treatment such as shot peening or shot blasting, but a sufficient effect is obtained. It has not reached.

  On the other hand, when a physical vapor deposition method is employed as a method for forming a coating layer, it is known that compressive residual stress is imparted to the coating layer. For this reason, the coating layer formed by the chemical vapor deposition method has the above-described properties. Can solve various problems. However, the coating layer formed by such a physical vapor deposition method has a problem that it is easily peeled off from the substrate because of poor adhesion to the substrate.

  Thus, it is thought that the chemical vapor deposition method and the physical vapor deposition method as a method of forming a coating layer on a base material have merits and demerits, respectively. For this reason, it has been attempted to use both of these in combination for the purpose of complementing these disadvantages. Specifically, a coating layer is first formed on the base material by chemical vapor deposition, and further a coating layer is formed thereon by physical vapor deposition, thereby adjusting the stress of the entire coating layer and the advantages of both. It has been attempted to promote (Patent Documents 1 to 4).

However, although some improvement can be achieved by the above-described attempts, in recent cutting work sites where high wear resistance is required for cutting tools, further improvement in performance is required.
Japanese Patent Laid-Open No. 64-03760 Japanese Patent Laid-Open No. 08-318410 JP-A-10-225805 Japanese Patent Laid-Open No. 11-061437

  The present invention has been made in view of the current situation as described above, and an object thereof is to provide a surface-coated cutting tool having a highly improved wear resistance.

  The surface-coated cutting tool of the present invention comprises a base material and a coating layer formed on the base material, and the coating layer is one or more chemical vapor deposition layers formed by a chemical vapor deposition method. And one or more physical vapor deposition layers formed by physical vapor deposition on the chemical vapor deposition layer, the physical vapor deposition layer includes a super multi-layer structure layer or a modulation structure layer, and the super multi-layer structure layer includes: At least one element selected from the group consisting of group IVa, element Va, group VIa, Al, and Si in the periodic table, and at least one selected from the group consisting of carbon, nitrogen, oxygen, and boron Two or more types of unit layers composed of a compound consisting of the above elements have a structure in which each of them is periodically and repeatedly laminated with a thickness of 0.2 nm or more and 20 nm or less. IVa group element, Va group element, VIa group A composition comprising at least one element selected from the group consisting of elemental, Al, and Si and at least one element selected from the group consisting of carbon, nitrogen, oxygen, and boron; Alternatively, it has a structure in which the composition ratio changes in a cycle of 0.2 nm to 40 nm in the thickness direction.

  Here, it is preferable that at least one of the chemical vapor deposition layers has a compressive residual stress, and the physical vapor deposition layer includes one or more hard layers in addition to the super multi-layer structure layer or the modulation structure layer. And the hard layer is composed of at least one element selected from the group consisting of group IVa element, group Va element, group VIa element, Al, and Si in the periodic table, or at least one of the elements It can be comprised by the compound which consists of 1 type and at least 1 type of element chosen from the group which consists of carbon, nitrogen, oxygen, and boron.

  The chemical vapor deposition layer preferably has a thickness of 1 μm to 30 μm, and the physical vapor deposition layer preferably has a thickness of 0.01 μm to 10 μm.

  Further, the base material is preferably composed of any one of cemented carbide, cermet, high speed steel, ceramics, cubic boron nitride sintered body, diamond sintered body, or silicon nitride sintered body, The above surface-coated cutting tools include drills, end mills, milling cutting edge replacement cutting tips, turning cutting edge replacement cutting tips, metal saws, gear cutting tools, reamers, taps, or crankshaft pin milling cutting edge replacement types. It is preferably one of cutting tips.

  The present invention also includes a base material and a coating layer formed on the base material, the coating layer having one or more chemical vapor deposition layers formed by chemical vapor deposition, and a physical layer on the chemical vapor deposition layer. One or more physical vapor deposition layers formed by a vapor deposition method, wherein the physical vapor deposition layer relates to a method of manufacturing a surface-coated cutting tool including a super multi-layer structure layer or a modulation structure layer. Forming one or more chemical vapor deposition layers by chemical vapor deposition, and performing bombarding on the outermost surface of the chemical vapor deposition layer and forming one or more physical vapor deposition layers by physical vapor deposition And applying a compressive residual stress to at least one of the chemical vapor deposition layers.

  The surface-coated cutting tool of the present invention has a highly improved wear resistance by having the above-described configuration.

Hereinafter, the present invention will be described in more detail.
<Surface coated cutting tool>
The surface-coated cutting tool of the present invention comprises a base material and a coating layer formed on the base material. The surface-coated cutting tool of the present invention having such a configuration is, for example, a drill, an end mill, a milling cutting edge replacement cutting tip, a turning cutting edge replacement cutting tip, a metal saw, a gear cutting tool, a reamer, a tap, or a crank. It is extremely useful as a cutting edge exchangeable cutting tip for shaft pin milling.

<Base material>
As a material constituting the substrate of the present invention, a conventionally known material known as a substrate for such a surface-coated cutting tool can be used without any particular limitation. For example, cemented carbide (for example, including WC base cemented carbide, including WC, Co, or further including carbides such as Ti, Ta, Nb, nitrides, carbonitrides, etc.), cermet (Mainly composed of TiC, TiN, TiCN, etc.), high-speed steel, ceramics (such as titanium carbide, silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, and mixtures thereof), cubic boron nitride firing Examples thereof include a sintered body, a diamond sintered body, and a silicon nitride sintered body.

  In addition, these substrates may be those whose surfaces are modified. For example, in the case of cemented carbide, a de-β layer, β phase enriched layer or Co phase enriched layer may be formed on the surface, and in the case of cermet, a surface hardened layer may be formed. Even if the surface is modified, the effect of the present invention is exhibited. In the case of cemented carbide or cermet, the effect of the present invention is shown regardless of the presence or absence of free carbon and ε phase in the alloy structure.

<Coating layer>
The coating layer of this invention is formed on said base material. The covering layer may be formed so as to cover the entire surface of the base material, or may be formed so as to cover only a part of the base material. Since it is in the improvement (that is, the improvement of the cutting performance), it is preferable to cover at least a part of the portion that contributes to the improvement of the cutting performance even when the whole surface of the substrate is covered or a part thereof is covered.

  Such a coating layer includes one or more chemical vapor deposition layers formed by a chemical vapor deposition method (CVD method) and one or more physical vapor deposition layers formed by a physical vapor deposition method (PVD method) on the chemical vapor deposition layer. The physical vapor deposition layer is characterized in that it includes a super multi-layer structure layer or a modulation structure layer.

  As described above, when the coating layer includes one or more chemical vapor deposition layers, adhesion to the base material as a whole coating layer is improved and toughness is improved by including one or more physical vapor deposition layers. It is. In particular, the coating layer includes a chemical vapor deposition layer, and the physical vapor deposition layer includes an ultra-multilayer structure layer or a modulation structure layer. It has become possible to achieve both a high degree of compatibility between toughness and toughness.

  In addition, it is preferable that the thickness (total thickness) of the coating layer of this invention is 1 micrometer or more and 40 micrometers or less. If the thickness is less than 1 μm, the effect of improving various properties such as wear resistance is not sufficiently exhibited. On the other hand, if the thickness exceeds 40 μm, no further improvement in the various properties is observed. It is not advantageous. However, as long as economic efficiency is ignored, the thickness may be 40 μm or more, and the effect of the present invention is shown. As a method for measuring such thickness, for example, a surface-coated cutting tool can be cut, and the cross section can be measured by observing using a SEM (scanning electron microscope).

<Chemical vapor deposition layer>
The coating layer of the present invention includes one or more chemical vapor deposition layers. The chemical vapor deposition layer is formed on the base material so as to be in contact with the base material, and is formed by a chemical vapor deposition method. As such a chemical vapor deposition method, a conventionally known method can be used without any particular limitation, and the conditions and the like are not limited. For example, a film forming temperature of about 850 to 1050 ° C. can be adopted, and a conventionally known gas such as a nitrile gas can be used without particular limitation as a gas to be used.

  Each layer of such a chemical vapor deposition layer is composed of group IVa elements (Ti, Zr, Hf, etc.), group Va elements (V, Nb, Ta, etc.), group VIa elements (Cr, Mo, W, etc.), Composed of at least one element selected from the group consisting of Al and Si, or at least one element selected from the group consisting of carbon, nitrogen, oxygen, and boron; It is preferable that it is comprised by the compound which consists of.

As the element or compound as described above, for example Cr, Ti, Al, Si, V, Zr, Hf, TiC, TiN, TiCN, TiNO, TiCNO, TiB 2, TiO 2, TiBN, TiBNO, TiCBN, ZrC, ZrO _{2, HfC, HfN, TiAlN,} AlCrN, CrN, VN, TiSiN, TiSiCN, AlTiCrN, TiAlCN, ZrCN, ZrCNO, Al 2 O 3, AlN, AlCN, ZrN, TiAlC, NbC, NbN, NbCN, Mo 2 C, WC , W ₂ C and the like. In the present invention, when the compound is represented by the chemical formula as described above, it is assumed that all the conventionally known atomic ratios are included unless the atomic ratio is particularly limited, and are not necessarily limited to those in the stoichiometric range. . For example, when simply describing “TiCN”, the atomic ratio of “Ti”, “C”, and “N” is not limited to 50:25:25, and also when “TiN” is described, “Ti” and “N” The atomic ratio is not limited to 50:50. These atomic ratios include all conventionally known atomic ratios (the same applies to the following physical vapor deposition layers and examples).

  And as for such a chemical vapor deposition layer, it is especially preferable that at least 1 layer has a compressive residual stress. Thereby, the extremely excellent effect that the toughness of the chemical vapor deposition layer is remarkably improved and the propagation of cracks generated during the cutting process can be effectively prevented is shown. As described above, when at least one of the chemical vapor deposition layers has compressive residual stress and the physical vapor deposition layer includes the super multi-layer structure layer or the modulation structure layer as described above, they act synergistically and have extremely high resistance. It is possible to achieve both wear and toughness.

  Here, as a method of applying compressive residual stress to the chemical vapor deposition layer of the present invention, as described later, there is a method of performing a bombarding treatment on the outermost surface of the chemical vapor deposition layer (the surface of the uppermost layer in contact with the physical vapor deposition layer) Adopted. Since the chemical vapor deposition layer is formed by the chemical vapor deposition method, it will have a tensile residual stress if no treatment is performed, but as a method of not only releasing this tensile residual stress but also applying a compressive residual stress, The effectiveness of such a bombarding process has been clarified for the first time by research of the inventors of the present invention, and constitutes one of the technical features of the present invention.

  Conventionally, it has been known that shot peening is applied to the surface of a chemical vapor deposition layer (Patent Document 4). However, the tensile residual stress is only released by this treatment, and compressive residual stress cannot be applied. There wasn't. It is conceivable to perform blasting instead of shot peening, but when forming a physical vapor deposition layer on a chemical vapor deposition layer, performing such blasting can greatly reduce work efficiency. become. On the other hand, since the bombarding process employed by the present invention can be performed in an apparatus for forming a physical vapor deposition layer, the industrial efficiency is extremely large due to excellent work efficiency.

  The expression bombardment in the present invention includes normal bombardment, and the physical vapor deposition layer is not formed by adjusting the conditions when the physical vapor deposition layer is formed by the physical vapor deposition method. It is intended to include cases where only residual stress is applied.

  Here, the compressive residual stress is a kind of internal stress (intrinsic strain) existing in such a coating layer, and is represented by a numerical value “−” (minus) (unit: “GPa” is used in the present invention). Refers to the stress applied. For this reason, the concept that the compressive residual stress is large indicates that the absolute value of the numerical value is large, and the concept that the compressive residual stress is small indicates that the absolute value of the numerical value is small. Incidentally, the tensile residual stress is a kind of internal stress (intrinsic strain) existing in the coating layer, and means a stress represented by a numerical value “+” (plus). Note that the term “residual stress” includes both compressive residual stress and tensile residual stress.

  The compressive residual stress is preferably a stress having an absolute value of 0.1 GPa or more, more preferably 0.2 GPa or more, and further preferably 0.5 GPa or more. If the absolute value is less than 0.1 GPa, sufficient toughness may not be obtained, and the above excellent effects may not be obtained. On the other hand, the larger the absolute value, the better from the viewpoint of imparting toughness. However, when the absolute value exceeds 6 GPa, the layer itself may be broken or peeled off.

Such compressive residual stress (residual stress) can be measured by the sin ² ψ method using an X-ray stress measurement apparatus. And such a compressive residual stress is arbitrary points (1 point, preferably 2 points, more preferably 3 to 5 points, more preferably 10 points ( Each point when measuring at a plurality of points is preferably selected with a distance of 0.1 mm or more away from each other so that the stress of the layer can be represented))) by the sin ² ψ method, and the average It can be measured by determining the value.

The sin ² ψ method using X-rays is widely used as a method for measuring the residual stress of a polycrystalline material. For example, “X-ray stress measurement method” (Japan Society of Materials Science, 1981 Corporation) The method described in detail on pages 54 to 67 of Yokendo) may be used.

  The compressive residual stress can also be measured by using a method using Raman spectroscopy. Such Raman spectroscopy has the merit that local measurement can be performed in a narrow range, for example, a spot diameter of 1 μm. The measurement of residual stress using such Raman spectroscopy is common, but for example, "Thin film mechanical property evaluation technique" (Sipec (currently renamed Realize Science and Technology Center), published in 1992. ), Pages 264 to 271 can be employed.

  Furthermore, the compressive residual stress can also be measured using synchrotron radiation. In this case, there is an advantage that the distribution of residual stress can be obtained in the thickness direction of the coating layer.

  In addition, the thickness of the chemical vapor deposition layer of the present invention (when formed by two or more layers, the total thickness) is preferably 1 μm or more and 30 μm or less, more preferably 2 μm or more and 20 μm or less. If the thickness is less than 1 μm, the effect of improving the wear resistance is not sufficiently exhibited. On the other hand, if the thickness exceeds 30 μm, no further improvement in various properties is observed, which is not economically advantageous. However, as long as economic efficiency is ignored, the thickness can be 30 μm or more, and the effect of the present invention is shown. As a method for measuring such thickness, for example, a surface-coated cutting tool can be cut, and the cross section can be measured by observing using a SEM (scanning electron microscope).

<Preferred configuration of chemical vapor deposition layer>
The chemical vapor deposition layer of the present invention preferably includes a chemical vapor deposition alumina layer mainly containing alumina (aluminum oxide (Al ₂ O ₃ )). The chemical vapor deposition alumina layer preferably has a compressive residual stress. Since the chemical vapor deposition alumina layer is formed by a chemical vapor deposition method, it is formed in a state having a tensile residual stress as described above, but a compressive residual stress can be imparted by performing the above treatment. Thus, when the chemical vapor deposition alumina layer has compressive residual stress, good toughness can be imparted particularly at the cutting edge of the cutting tool.

  The thickness of such a chemical vapor deposition alumina layer is preferably 0.3 μm or more and 20 μm or less, more preferably the lower limit is 0.5 μm or more, more preferably 1 μm or more, and the upper limit is 15 μm or less, more preferably 10 μm. The following is preferable. If the thickness of the chemically vapor-deposited alumina layer is less than 0.3 μm, the effect of improving the wear resistance may be reduced, and if it exceeds 20 μm, the wear resistance is not significantly improved, which is not industrially preferable. There is a case.

  Here, containing alumina as a main component means containing 50% by mass or more of alumina, and more preferably, it is composed only of alumina excluding inevitable impurities. The crystal structure of alumina can be identified by X-ray diffraction (XRD).

  Such a chemical vapor deposition alumina layer is preferably formed as the uppermost layer of the chemical vapor deposition layer (a layer in contact with the physical vapor deposition layer). In other words, the physical vapor deposition layer is preferably formed on the chemical vapor deposition alumina layer. By setting it as the aspect of such a lamination | stacking, especially abrasion resistance and toughness can be made to make highly compatible. In addition, a layer containing alumina as a main component, such as a chemical vapor deposition alumina layer, has a strong tendency to have a black appearance color. However, if such a configuration is used, a cutting tool can be used if the physical vapor deposition layer has a light color. There is also an advantage that it is possible to easily discriminate the usage state.

  The chemical vapor deposition layer of the present invention preferably includes a layer containing TiCN formed by a low temperature chemical vapor deposition method. This is because a layer containing titanium carbonitride (TiCN) having excellent wear resistance can be formed while reducing damage to the substrate due to application of heat.

  The thickness of the layer containing TiCN is preferably 0.3 μm or more and 20 μm or less, more preferably the lower limit is 0.5 μm or more, more preferably 1 μm or more, and the upper limit is 15 μm or less, and more preferably 10 μm. The following is preferable. If the thickness of this layer is less than 0.3 μm, it may not be possible to sufficiently improve the wear resistance, and if it exceeds 20 μm, the wear resistance will not be significantly improved, and this is not industrially desirable. There is.

Here, the low-temperature chemical vapor deposition method is often compared with the conventional chemical vapor deposition method as described above, in which film formation is performed at about 950 to 1050 ° C., compared to about 830 to 950 ° C. This method is performed at a low temperature, and is sometimes referred to as MT-CVD (medium temperature CVD). This method is preferable because damage to the substrate due to heating during film formation can be reduced. In this case, a nitrile gas, particularly acetonitrile (CH ₃ CN) is preferably used as the gas used for film formation because of excellent mass productivity.

  In addition, the chemical vapor deposition layer of the present invention includes a layer formed by the MT-CVD method as described above, and a layer formed by the HT-CVD method (high temperature CVD, the above-described chemical vapor deposition method under normal conditions). Adhesive strength between each of these layers may be improved and may be preferable by having a multilayer structure in which is laminated.

<Physical vapor deposition layer>
The physical vapor deposition layer of the present invention is formed on the above chemical vapor deposition layer by physical vapor deposition, and consists of one or more layers. As such a physical vapor deposition method, any conventionally known physical vapor deposition method can be adopted and is not particularly limited. Examples of such physical vapor deposition include magnetron sputtering, arc ion plating, holocathode, ion beam, electron beam, balanced magnetron sputtering, unbalanced magnetron sputtering, and dual magnetron sputtering. Can be mentioned.

  Among the methods exemplified above, it is particularly preferable to employ the arc type ion plating method. This is because compressive residual stress can be applied to the physical vapor deposition layer very effectively. In addition, it is preferable to employ | adopt the apparatus which provided each ion source used for the above methods as an apparatus which performs a physical vapor deposition method.

  Since the physical vapor deposition layer of the present invention is formed by a physical vapor deposition method, it has a compressive residual stress. Thereby, the above excellent effects can be shown. Such measurement of compressive residual stress can be performed by the same method as described above.

  The compressive residual stress is preferably a stress having an absolute value of 0.1 GPa or more, more preferably 0.2 GPa or more, and further preferably 0.5 GPa or more. If the absolute value is less than 0.1 GPa, sufficient toughness may not be obtained, and the above excellent effects may not be obtained. On the other hand, the larger the absolute value, the better from the viewpoint of imparting toughness. However, when the absolute value exceeds 6 GPa, the layer itself may be broken or peeled off.

  In addition, it is preferable that the thickness (total thickness) of the physical vapor deposition layer of this invention is 0.01 micrometer or more and 10 micrometers or less, More preferably, they are 0.1 micrometer or more and 8 micrometers or less. If the thickness is less than 0.01 μm, spots may appear in the color tone of the appearance. On the other hand, if it exceeds 10 μm, the layer itself self-destructs or peels off, so that the toughness of the cutting edge of the cutting tool decreases. It is not preferable.

  The physical vapor deposition layer of the present invention includes a super multilayer structure layer or a modulation structure layer. Hereinafter, these will be described.

<Super multilayer structure layer>
The super multi-layer structure layer of the present invention is composed of IVa group elements (Ti, Zr, Hf, etc.), Va group elements (V, Nb, Ta, etc.), VIa group elements (Cr, Mo, W, etc.), Al, etc. And at least one unit layer composed of a compound comprising at least one element selected from the group consisting of Si and at least one element selected from the group consisting of carbon, nitrogen, oxygen, and boron. , Each of which has a structure in which the layers are periodically and repeatedly stacked with a thickness of 0.2 nm to 20 nm. By forming the super multi-layer structure layer as a physical vapor deposition layer in this way, extremely excellent wear resistance is imparted in combination with the formation of the above chemical vapor deposition layer (especially a chemical vapor deposition layer having compressive residual stress). be able to.

  Here, the term “repetitively laminating” means having a certain periodicity, for example, when laminating two types of unit layers alternately up and down, or when laminating three types of unit layers repeatedly upper, middle, and lower. It means to laminate. If the thickness of each unit layer is less than 0.2 nm or exceeds 20 nm, the effect of improving the wear resistance by the super multi-layer structure layer may not be shown. The thickness of each unit layer can be appropriately adjusted depending on the composition constituting the unit layer and the film forming conditions. Each unit layer may have substantially the same thickness or may have a different thickness.

The unit layer is composed of at least one element selected from the group consisting of group IVa elements, group Va elements, group VIa elements, Al, and Si in the periodic table, and carbon, nitrogen, oxygen, and boron. Examples of the compound composed of at least one element selected from the group consisting of TiC, TiN, TiCN, TiNO, TiCNO, TiB ₂ , TiO ₂ , TiBN, TiBNO, TiCBN, ZrC, ZrO ₂ , HfC, HfN, TiAlN , TiAlCrN, TiZrN, TiCrN, AlCrN , CrN, VN, TiSiN, TiSiCN, AlTiCrN, TiAlCN, ZrCN, ZrCNO, Al 2 O 3, AlN, AlCN, ZrN, TiAlC, NbC, NbN, NbCN, Mo 2 C, WC, W ₂ C and the like can be mentioned.

  The number of unit layers constituting the super multi-layer structure layer (total number of layers) is not particularly limited, but is usually preferably 10 or more and 5000 or less. If it is less than 10 layers, the crystal grains in each unit layer become coarse and the hardness of the coating layer may decrease. If it exceeds 5000 layers, each unit layer tends to be too thin and the layers tend to mix. It is.

  Such a super multi-layer structure layer is formed by a conventionally known physical vapor deposition method, and its manufacturing method is not particularly limited. Hereinafter, the case where the arc ion plating method is employed as the physical vapor deposition method will be exemplified.

  First, in the arc ion plating film forming apparatus, targets are set in a plurality of evaporation sources corresponding to the types of unit layers to be formed. Then, the substrate is set in the substrate holder in the chamber of the apparatus, and the target of the evaporation source is evaporated and ionized while rotating the substrate holder so as to face the evaporation source. Form. An example of more specific conditions is as follows.

  That is, the base material is heated by a heater installed in the chamber. Thereafter, the substrate surface is cleaned with argon ions for 1 to 120 minutes by introducing a bias voltage to the substrate while introducing argon gas and maintaining the pressure in the chamber at 1 to 10 Pa.

  Subsequently, after the argon gas in the chamber is exhausted, the reaction gas is introduced, and while maintaining the pressure in the chamber at 2 to 10 Pa, the substrate holder on which the substrate is set is rotated while the bias voltage ( -20 to -200 V) is applied, and the target set in the evaporation source is ionized, and the unit layers are sequentially stacked to form a super multi-layer structure layer.

<Modulation structure layer>
The modulation structure layer of the present invention includes at least one element selected from the group consisting of group IVa elements, group Va elements, group VIa elements, Al, and Si in the periodic table, and carbon, nitrogen, oxygen, and boron. It is comprised by the compound which consists of at least 1 sort (s) of elements chosen from the group which consists of, and the composition or composition ratio of the compound has a structure which changes with a period of 0.2 nm or more and 40 nm or less in the thickness direction. By forming the modulation structure layer as a physical vapor deposition layer in this way, it is possible to provide extremely excellent wear resistance in combination with the formation of the above chemical vapor deposition layer (especially a chemical vapor deposition layer having compressive residual stress). Can do.

  Here, the composition or composition ratio of the compound changes in the thickness direction with a period of 0.2 nm or more and 40 nm or less. For example, as shown in FIG. For example, in the thickness direction from the substrate side to the surface side of the modulation structure layer, the state A at the point X first gradually changes to the state B at the point Y and gradually changes again. Then, when the state A is reached at the point Z, the distance between the points X and Z becomes a period (0.2 nm or more and 40 nm or less) (in this case, the point Y is located approximately at the midpoint between the points X and Z), and this Such a change in the state A-B-A is repeated in the same cycle. If the period is less than 0.2 nm or exceeds 40 nm, the effect of improving the wear resistance by the modulation structure layer may not be shown. A more preferable range of the period has an upper limit of 35 nm or less, more preferably 30 nm or less, and a lower limit of 0.5 nm or more, more preferably 1 nm or more.

  At least one element selected from the group consisting of Group IVa element, Group Va element, Group VIa element, Al, and Si of the periodic table constituting such a modulation structure layer, and carbon, nitrogen, oxygen, and boron Examples of the compound composed of at least one element selected from the group consisting of include the same compounds as those exemplified in the super multi-layer structure layer.

  Such a modulation structure layer can be formed by a manufacturing method similar to the manufacturing method of the super multi-layer structure layer described above, and particularly in the case of a modulation structure layer having a structure in which the composition ratio changes in the thickness direction. They can be formed by setting targets with different composition ratios in the evaporation source and controlling the number of rotations of the substrate holder.

  In addition, when the composition changes in the thickness direction, there may be no clear difference between the modulation structure layer and the super multi-layer structure layer, but it is not necessary to clearly distinguish such a difference. These do not depart from the scope of the present invention.

<Hard layer>
The physical vapor deposition layer of the present invention can include one or more hard layers in addition to the super multi-layer structure layer or the modulation structure layer. Such a hard layer is constituted by at least one element selected from the group consisting of group IVa elements, group Va elements, group VIa elements, Al, and Si in the periodic table, or at least one of the elements It can be constituted by a compound comprising a seed and at least one element selected from the group consisting of carbon, nitrogen, oxygen, and boron.

  Such a hard layer is preferably formed on the super multi-layer structure layer or the modulation structure layer (that is, on the surface side of the coating layer), thereby stabilizing the appearance color of the coating layer, The effect that heat dissipation improves can be provided. The hard layer can also be formed on the chemical vapor deposition layer. Thereby, the effect | action that the adhesiveness of a chemical vapor deposition layer and a physical vapor deposition layer can be improved can be provided. As described above, the hard layer can be formed at any position in the physical vapor deposition layer.

  Further, the thickness of the hard layer (total thickness when two or more layers are formed) is preferably 0.05 μm or more and 5 μm or less, more preferably the upper limit is 3 μm or less, and further preferably 1 μm or less. The lower limit is 0.1 μm or more, more preferably 0.15 μm or more. If the thickness is less than 0.05 μm, the effect of improving the wear resistance may not be exhibited. If the thickness exceeds 5 μm, the hard layer may be easily chipped and the tool life may be shortened.

Examples of the elements or compounds constituting such a hard layer include Cr, Ti, Al, Si, V, Zr, Hf, TiC, TiN, TiCN, TiNO, TiCNO, TiB ₂ , TiO ₂ , TiBN, TiBNO, and TiCBN. , ZrC, ZrO ₂ , HfC, HfN, TiAlN, AlCrN, CrN, VN, TiSiN, TiSiCN, AlTiCrN, TiAlCN, ZrCN, ZrCNO, Al ₂ O ₃ , AlN, AlCN, ZrN, TiAlC, NbC, NbN, NbCN ₂ C, WC, W ₂ C and the like.

  Such a hard layer is formed by a conventionally known physical vapor deposition method, and its manufacturing method is not particularly limited.

<Manufacturing method>
The surface-coated cutting tool of the present invention configured as described above can be manufactured by the following manufacturing method. That is, the manufacturing method includes a step of forming one or more chemical vapor deposition layers on a substrate by chemical vapor deposition, and performing bombarding on the outermost surface of the chemical vapor deposition layer, thereby at least forming the chemical vapor deposition layer. A step of imparting compressive residual stress to one layer, and a step of forming one or more physical vapor deposition layers on the chemical vapor deposition layer subjected to the bombarding treatment by a physical vapor deposition method. The manufacturing method may include other steps as long as the above steps are included.

  In the above, the step of applying compressive residual stress and the step of forming a physical vapor deposition layer include performing bombarding on the outermost surface of the chemical vapor deposition layer and forming one or more physical vapor deposition layers by physical vapor deposition. By forming it, it can be handled as one step, such as a step of applying compressive residual stress to at least one of the chemical vapor deposition layers.

  Here, the chemical vapor deposition method employed in the step of forming the chemical vapor deposition layer may employ any conditions as long as it is a conventionally known chemical vapor deposition method as described above.

  Moreover, the bombarding process employed in the step of applying compressive residual stress to at least one of the chemical vapor deposition layers may be any of the conventionally known conditions. For example, a gas bombardment using argon gas or the like can be adopted, and a metal bombardment using a metal such as Ti, TiAl, TiSi, or AlCr can also be adopted. Further, when metal bombardment is employed, it may be performed under vacuum (under reduced pressure) or in the presence of a gas such as nitrogen. As a particularly suitable condition for applying the compressive residual stress, for example, it is preferable to employ a bias voltage higher than the bias voltage when forming the physical vapor deposition layer.

  Moreover, the physical vapor deposition method employ | adopted in the process of forming a physical vapor deposition layer can employ | adopt any conditions as long as it is a conventionally well-known physical vapor deposition method as above-mentioned. The super multi-layer structure layer or modulation structure layer included in the physical vapor deposition layer can be formed by the manufacturing method described above.

  In the above manufacturing method, the bombardment process and the physical vapor deposition layer performed after the chemical vapor deposition layer is formed are performed after the chemical vapor deposition layer is formed on the substrate and then taken out into the atmosphere. Alternatively, it may be performed continuously in the same apparatus.

  Note that the bombardment process and the physical vapor deposition layer can be continuously performed in the same apparatus, and thus have an advantage of extremely high production efficiency.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

<Example 1>
Pressing cemented carbide powder of 1.2 wt% TaC, 1.0 wt% TiC, 7.1 wt% Co and the balance WC (including inevitable impurities), followed by vacuum JIS B4120 (1998) by sintering at 1440 ° C. for 1 hour, followed by surface grinding and edge treatment with a SiC brush (honing 0.06 mm width as viewed from the rake face side). (Revision) A chip made of cemented carbide having the same shape as the prescribed cutting chip CNMA120404 was produced and used as a base material. This substrate had a 13.5 μm deβ layer formed on the surface.

  Next, a plurality of the substrates were prepared, the chemical vapor deposition layers described in Table 1 below were formed on the individual substrates, and the physical vapor deposition layers described in Table 2 or Table 3 below were formed thereon ( For example, the surface-coated cutting tool of No. 101 shows that the chemical vapor deposition layer shown in Table 1 was formed on the substrate, and then the physical vapor deposition layer shown in Table 2 was formed after bombarding. A specific forming method is as follows.

  That is, one or more chemical vapor deposition layers described in Table 1 below were formed on each of the above substrates by chemical vapor deposition (specific conditions for forming each layer are described in Table 6; Table 1 Each condition was sequentially adopted according to the laminated structure. Next, by performing the bombardment process described in Table 1 below on the outermost surface of the chemical vapor deposition layer formed in this way (specific conditions according to the type of each bombardment process are described in Table 7), A compressive residual stress was applied to at least one of the chemical vapor deposition layers. Subsequently, an arc-type ion plating method or an unbalanced magnetron sputtering method, which is a physical vapor deposition method, is applied to the chemical vapor deposition layer thus subjected to the bombarding process (specific conditions for forming each layer are described in Tables 8 to 12). (In the table, what is described as “arc evaporation source” indicates that it was formed by the arc ion plating method, and what is described as “sputter evaporation source” is unbalanced. 1) showing one or more physical vapor depositions described in Table 2 or Table 3 below according to the laminated structure shown in Table 2 or Table 3). A surface-coated cutting tool was produced by forming a layer. Note that all the above processes were performed continuously in one film forming apparatus (see FIG. 2). That is, as shown in FIG. 2, the film forming apparatus 10 includes a substrate table 11 that supports the substrate 1, a plurality of heaters 12, a first evaporation source 13, a second evaporation source 14, and a third evaporation source. 15 and a gas inlet 16. The third evaporation source 15 may or may not be used.

For comparison, a surface-coated cutting tool having the configuration described in Table 4 was also manufactured.
That is, No. 1 in Tables 1 to 3 below. Nos. 101 to 110 are surface-coated cutting tools according to examples of the present invention. Reference numerals 111 to 117 denote surface-coated cutting tools of comparative examples. A surface-coated cutting tool according to an embodiment of the present invention includes a substrate and a coating layer formed on the substrate, and the coating layer includes one or more layers formed by a chemical vapor deposition method. A chemical vapor deposition layer and one or more physical vapor deposition layers formed by physical vapor deposition on the chemical vapor deposition layer, the physical vapor deposition layer comprising a super multi-layer structure layer or a modulation structure layer, At least one layer (chemical vapor deposition alumina layer) had compressive residual stress.

  No. The surface-coated cutting tool of Comparative Example 111 is No. 101 has a chemical vapor deposition layer having the same configuration as the chemical vapor deposition layer of the surface-coated cutting tool of Example 101. Similarly, Comparative Example No. The surface-coated cutting tools 112, 113, 114, 115, 116, and 117 are each of Example No. It had the chemical vapor deposition layer of the same structure as the chemical vapor deposition layer of the surface coating cutting tool of 104, 105, 106, 107, 109, 110.

In Tables 1 and 4 below, the chemical formula in the column of the chemical vapor deposition layer indicates the composition of each layer constituting the chemical vapor deposition layer, and the numerical value in the column is “thickness (μm)” (α-Al ₂ O ₃ or κ-Al _{For the} layer represented by ₂ O ₃ (that is, chemical vapor deposition alumina layer), “residual stress (GPa) / thickness (μm)”) is shown (a negative value of the residual stress indicates a compressive residual stress, plus The value of (no negative sign) indicates tensile residual stress). In addition, it shows that each layer shown by the chemical formula was formed on the base material in order from the left one (two or more layers are those on the left side of the upper stage), and “MT-TiCN” is a layer made of TiCN above “HT-TiCN” indicates that a layer made of TiCN was formed by the above-described HT-CVD method (a layer described simply as “TiCN” is MT-CVD). It shows that it was formed by the CVD method). In addition, α-Al ₂ O ₃ and κ-Al ₂ O ₃ (α indicates that the crystal structure is α-type and κ indicates that the crystal structure is κ-type) are chemical vapor deposition mainly composed of them. Indicates an alumina layer. The residual stress was measured by the above method (sin ² ψ method) after manufacturing the surface-coated cutting tool.

  In Table 1 below, the column of bombard treatment indicates the type of bombard treatment (time indicates the time when bombard treatment was performed, Ti bombard indicates metal bombardment by Ti (titanium), and gas bombard is argon gas. These specific conditions are shown in Table 7).

  In Table 2 below, No. In 101 to 105, the two types of unit layers constituting each super multi-layer structure layer have the same thickness. However, in the present invention, the thickness between each unit layer is not necessarily limited to the same one. Even if they are different, the effect of the present invention is shown.

  In Table 3 below, No. The modulation structure layer 106, which is a physical vapor deposition layer, will be described with reference to FIG. That is, if Ti / Al (atomic ratio) is 1.15 (ie, state A) at an arbitrary point X in the thickness direction of the modulation structure layer, Ti / Al is 0.85 (ie, state B) at point Y. In addition, at the point Z, Ti / Al becomes 1.15 (that is, state A). In this case, the distance between the point X and the point Z is 25 nm, which is a cycle. This indicates that the change in the state A-B-A is repeated and the thickness of the modulation structure layer becomes 1.8 μm.

  In Table 4 below, a blank (“-”) indicates that the corresponding treatment and layer were not implemented / formed.

The surface-coated cutting tool obtained above was subjected to an abrasion resistance test under the following conditions to measure the flank average wear width (V _B ). The results are shown in Table 5 below. The flank average wear width (V _B ) indicates that the smaller the value, the better the wear resistance.

<Conditions for wear resistance test>
Holder used: PCLNR2525-43 (Sumitomo Electric Hardmetal)
Work material: SCM435 (HB = 246) round bar Cutting speed: 273 m / min.
Feed: 0.25mm / rev.
Cutting depth: 2mm
Wet / dry: wet (water-soluble oil)
Cutting time: 6 minutes As is clear from Table 5, it is clear that the surface-coated cutting tool of the example of the present invention has a highly improved wear resistance as compared with the surface-coated cutting tool of the comparative example. It is.

  In addition, although the base material of the surface coating cutting tool of a present Example does not have a chip breaker, the effect of this invention is exhibited also about what has a chip breaker. In addition, the present embodiment shows an example of turning using a negative tip as a cutting tip, but the effect of the present invention is also exhibited in the case of turning with a positive tip or milling with a negative tip or a positive tip. Moreover, although the de-β layer is formed on the base material of this example, the effect of the present invention is exhibited even if the de-β layer is not formed.

  Although the embodiments and examples of the present invention have been described as described above, it is also planned from the beginning to appropriately combine the configurations of the above-described embodiments and examples.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is the graph which illustrated notionally the structure of the modulation structure layer contained in a physical vapor deposition layer. It is the schematic of a film-forming apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Base material, 10 Film-forming apparatus, 11 Base material table, 12 Heater, 13 1st evaporation source, 14 2nd evaporation source, 15 3rd evaporation source, 16 Gas inlet.

Claims (7)

A surface-coated cutting tool comprising a substrate and a coating layer formed on the substrate,
The coating layer includes one or more chemical vapor deposition layers formed by chemical vapor deposition, and one or more physical vapor deposition layers formed by physical vapor deposition on the chemical vapor deposition layer,
The physical vapor deposition layer includes a super multi-layer structure layer or a modulation structure layer,
The super multi-layer structure layer includes at least one element selected from the group consisting of group IVa elements, group Va elements, group VIa elements, Al, and Si in the periodic table, and carbon, nitrogen, oxygen, and boron. Two or more types of unit layers composed of a compound composed of at least one element selected from the group have a structure in which each layer is periodically and repeatedly laminated with a thickness of 0.2 nm or more and 20 nm or less,
The modulation structure layer includes at least one element selected from the group consisting of group IVa element, group Va element, group VIa element, Al, and Si in the periodic table, and a group consisting of carbon, nitrogen, oxygen, and boron. A surface-coated cutting tool comprising a compound composed of at least one element selected from the above, and having a structure in which the composition or composition ratio of the compound changes in a cycle of 0.2 nm to 40 nm in the thickness direction.   The surface-coated cutting tool according to claim 1, wherein at least one of the chemical vapor deposition layers has a compressive residual stress. The physical vapor deposition layer includes one or more hard layers in addition to the super multi-layer structure layer or the modulation structure layer,
The hard layer is composed of at least one element selected from the group consisting of group IVa elements, group Va elements, group VIa elements, Al, and Si in the periodic table, or at least one of the elements and The surface-coated cutting tool according to claim 1 or 2, comprising a compound comprising at least one element selected from the group consisting of carbon, nitrogen, oxygen, and boron.   The surface-coated cutting tool according to claim 1, wherein the chemical vapor deposition layer has a thickness of 1 μm to 30 μm, and the physical vapor deposition layer has a thickness of 0.01 μm to 10 μm.   The said base material is comprised with either a cemented carbide alloy, a cermet, high-speed steel, ceramics, a cubic boron nitride sintered compact, a diamond sintered compact, or a silicon nitride sintered compact. The surface coating cutting tool in any one.   The surface-coated cutting tools include drills, end mills, milling cutting edge replacement cutting tips, turning cutting edge replacement cutting tips, metal saws, gear cutting tools, reamers, taps, or crankshaft pin milling cutting edge replacement types. The surface-coated cutting tool according to any one of claims 1 to 5, which is any one of cutting tips. A substrate and a coating layer formed on the substrate, wherein the coating layer is formed by one or more chemical vapor deposition layers formed by a chemical vapor deposition method and a physical vapor deposition method on the chemical vapor deposition layer One or more physical vapor deposition layers, wherein the physical vapor deposition layer is a method for producing a surface-coated cutting tool comprising a super multi-layer structure layer or a modulation structure layer,
Forming one or more chemical vapor deposition layers on the substrate by chemical vapor deposition;
Applying a compressive residual stress to at least one of the chemical vapor deposition layers by performing bombarding on the outermost surface of the chemical vapor deposition layer and forming one or more physical vapor deposition layers by physical vapor deposition; A method for manufacturing a surface-coated cutting tool comprising:

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