WO2016190332A1 - Surface-coated cutting tool with rigid coating layer exhibiting excellent chipping resistance - Google Patents

Surface-coated cutting tool with rigid coating layer exhibiting excellent chipping resistance Download PDF

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WO2016190332A1
WO2016190332A1 PCT/JP2016/065396 JP2016065396W WO2016190332A1 WO 2016190332 A1 WO2016190332 A1 WO 2016190332A1 JP 2016065396 W JP2016065396 W JP 2016065396W WO 2016190332 A1 WO2016190332 A1 WO 2016190332A1
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layer
composite
crystal grains
average
nitride
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PCT/JP2016/065396
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French (fr)
Japanese (ja)
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光亮 柳澤
翔 龍岡
佐藤　賢一
健志 山口
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三菱マテリアル株式会社
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Priority claimed from JP2016101460A external-priority patent/JP6709536B2/en
Application filed by 三菱マテリアル株式会社 filed Critical 三菱マテリアル株式会社
Priority to CN201680029622.4A priority Critical patent/CN107614167A/en
Priority to EP16800036.2A priority patent/EP3305446A4/en
Priority to KR1020177035979A priority patent/KR20180011148A/en
Priority to US15/576,056 priority patent/US20180154463A1/en
Publication of WO2016190332A1 publication Critical patent/WO2016190332A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B27/00—Tools for turning or boring machines; Tools of a similar kind in general; Accessories therefor
    • B23B27/14—Cutting tools of which the bits or tips or cutting inserts are of special material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23C—MILLING
    • B23C5/00—Milling-cutters
    • B23C5/16—Milling-cutters characterised by physical features other than shape
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/36—Carbonitrides

Definitions

  • a technique for increasing the Al content ratio x to about 0.9 by forming a hard coating layer by a chemical vapor deposition method has also been proposed.
  • a TiCN layer and an Al 2 O 3 layer are used as inner layers, and a cubic structure or a hexagonal structure (Ti 1-x Al x ) including a cubic structure is formed thereon by chemical vapor deposition.
  • Covering N layer (where x is 0.65 to 0.90 in atomic ratio) as an outer layer and applying compressive stress of 100 to 1100 MPa to the outer layer improves heat resistance and fatigue strength of the coated tool It has been proposed to do.
  • the inventors of the present invention have made extensive studies by paying attention to the concentration change in the crystal grains of the (Ti 1-x Al x ) (C y N 1-y ) layer constituting the hard coating layer.
  • a periodic concentration change of Ti and Al is formed in the crystal grains having the cubic crystal structure of the 1-x Al x ) (C y N 1-y ) layer, a high load acts on the cutting edge.
  • a buffering action against a shearing force is generated, which suppresses the progress of cracks and improves the toughness of the (Ti, Al) (C, N) layer.
  • the direction of the periodic concentration change is a direction within 30 degrees with respect to the plane parallel to the tool substrate surface
  • the concentration change period The direction in which the density change period is minimized, and the direction in which the angle between the direction in which the density change period is minimum and the plane parallel to the surface of the tool substrate is within 30 degrees is referred to as It is abbreviated as “direction of concentration change of the invention”).
  • the average content ratio X avg and the average content ratio Y avg in the total amount of C and N in C are respectively 0.40 ⁇ X avg ⁇ 0.95, It is preferable that 0 ⁇ Y avg ⁇ 0.005 is satisfied, the period of the concentration change is 1 to 10 nm, and the average and minimum values of the maximal value of the Al content ratio x that varies periodically
  • the average difference is preferably 0.01 to 0.1.
  • a hexagonal crystal structure is formed at the grain boundary portion of the crystal nitride having a NaCl-type face-centered cubic structure of the composite nitride or composite carbonitride layer.
  • the lower the film formation temperature of the composite nitride or composite carbonitride layer the lower the proportion of pores in the initial film formation layer, the higher the hardness, or the composite Adhesive strength between the nitride or composite carbonitride layer and the lower layer is increased, and the peel resistance is improved.
  • the higher the film formation temperature of the composite nitride or composite carbonitride layer the higher the crystallinity and the effect of improving the wear resistance. Peeling resistance and wear resistance are improved by performing the process in two stages and making the first stage film formation at a lower temperature than the second stage film formation.
  • the lower layer and the upper layer shown in Table 6 were formed under the formation conditions shown in Table 3, respectively.
  • the coated tools 1 to 4 of the present invention are formed on the surfaces of the tool bases A to D with the target layer thickness ( ⁇ m) shown in Table 8 under the conditions of the comparative film forming process shown in Tables 4 and 5.
  • comparative coating tools 1 to 10 were produced by vapor-depositing a hard coating layer including at least a composite nitride or composite carbonitride layer of Ti and Al. At this time, by forming a hard coating layer so that the reaction gas composition on the surface of the tool base does not change with time during the film forming process of the (Ti 1-x Al x ) (C y N 1-y ) layer.
  • Comparative coated tools 1-10 were produced. Similar to the coated tools 1 to 10 of the present invention, the comparative coated tools 1 to 10 were formed with the lower layer and the upper layer shown in Table 6 under the formation conditions shown in Table 3.
  • WC powder, TiC powder, ZrC powder, TaC powder, NbC powder, Cr 3 C 2 powder, TiN powder and Co powder each having an average particle diameter of 1 to 3 ⁇ m are prepared.
  • Compounded in the formulation shown in Table 10 added with wax, ball mill mixed in acetone for 24 hours, dried under reduced pressure, press-molded into a green compact of a predetermined shape at a pressure of 98 MPa.
  • vacuum sintering is performed at a predetermined temperature within a range of 1370 to 1470 ° C. for 1 hour, and after sintering, the cutting edge is subjected to a honing process of R: 0.07 mm.
  • Tool bases E to G made of WC-base cemented carbide having an insert shape of CNMG120212 were produced.
  • cBN powder, TiN powder, TiC powder, Al powder, and Al 2 O 3 powder each having an average particle diameter in the range of 0.5 to 4 ⁇ m were prepared. These raw material powders are shown in Table 16. After blending into the blended composition, wet mixing with a ball mill for 80 hours, drying, and press-molding into a green compact with a diameter of 50 mm ⁇ thickness: 1.5 mm at a pressure of 120 MPa, and then this green compact Is sintered in a vacuum atmosphere at a pressure of 1 Pa at a predetermined temperature in the range of 900 to 1300 ° C. for 60 minutes to obtain a presintered body for a cutting edge piece, and this presintered body is separately prepared.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Vapour Deposition (AREA)
  • Cutting Tools, Boring Holders, And Turrets (AREA)

Abstract

Provided is a coated tool including a rigid coating layer which, when used in high-speed intermittent cutting, has excellent chipping resistance and fracture resistance and exhibits excellent wear resistance over a long period. The rigid coating layer comprises a composite nitride or composite carbonitride layer represented by the empirical formula (Ti1-xAlx)(CyN1-y). The rigid coating layer includes crystal grains of the composite nitride or composite carbonitride which have an NaCl-form face-centered cubic structure and in which there are periodic concentration changes, the directions of the periodic concentration changes at least include a direction that makes an angle of 30º or less with a plane parallel to the surface of the tool base. Preferably, the rigid coating layer has a columnar structure, the areal proportion of regions where there are periodic Ti/Al concentration changes is 40% by area or higher, the periods of concentration change are 1-10 nm, the difference between the average of maximal values of the Al content x that periodically changes and the average of minimal values thereof is 0.01-0.1, and at crystal grain boundaries, there are fine crystal grains of a hexagonal structure having an average grain diameter of 0.01-0.3 µm, in an amount of 5% by area or less.

Description

硬質被覆層がすぐれた耐チッピング性を発揮する表面被覆切削工具Surface coated cutting tool with excellent chipping resistance due to hard coating layer
　本発明は、合金鋼、鋳鉄、ステンレス鋼等の高熱発生を伴うとともに、切刃に対して衝撃的な負荷が作用する断続切削加工で、硬質被覆層がすぐれた耐チッピング性、耐剥離性を備えることにより、長期の使用に亘ってすぐれた切削性能を発揮する表面被覆切削工具（以下、被覆工具という）に関するものである。 The present invention has high heat generation of alloy steel, cast iron, stainless steel and the like, and is an intermittent cutting process in which an impact load is applied to the cutting edge, and has excellent chipping resistance and peeling resistance with a hard coating layer. The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool) that exhibits excellent cutting performance over a long period of use.
　従来、一般に、炭化タングステン（以下、ＷＣで示す）基超硬合金、炭窒化チタン（以下、ＴｉＣＮで示す）基サーメットあるいは立方晶窒化ホウ素（以下、ｃＢＮで示す）基超高圧焼結体で構成された工具基体（以下、これらを総称して工具基体という）の表面に、硬質被覆層として、Ｔｉ－Ａｌ系の複合窒化物層を物理蒸着法により被覆形成した被覆工具が知られており、これらは、すぐれた耐摩耗性を発揮することが知られている。
　ただ、前記従来のＴｉ－Ａｌ系の複合窒化物層を被覆形成した被覆工具は、比較的耐摩耗性にすぐれるものの、高速断続切削条件で用いた場合にチッピング等の異常損耗を発生しやすいことから、硬質被覆層の改善についての種々の提案がなされている。 Conventionally, generally composed of tungsten carbide (hereinafter referred to as WC) based cemented carbide, titanium carbonitride (hereinafter referred to as TiCN) based cermet or cubic boron nitride (hereinafter referred to as cBN) based ultra high pressure sintered body There is known a coated tool in which a Ti—Al-based composite nitride layer is formed by physical vapor deposition on the surface of a tool base (hereinafter collectively referred to as a tool base) as a hard coating layer, These are known to exhibit excellent wear resistance.
However, the conventional coated tool formed with the Ti—Al composite nitride layer is relatively excellent in wear resistance, but it tends to cause abnormal wear such as chipping when used under high-speed intermittent cutting conditions. Accordingly, various proposals have been made for improving the hard coating layer.
　例えば、特許文献１には、工具基体表面に、組成式（ＡｌｘＴｉ１－ｘ）Ｎ（ただし、原子比で、ｘは０．４０～０．６５）を満足するＡｌとＴｉの複合窒化物層からなり該複合窒化物層についてＥＢＳＤによる結晶方位解析を行った場合、表面研磨面の法線方向から０～１５度の範囲内に結晶方位＜１００＞を有する結晶粒の面積割合が５０％以上であり、また、隣り合う結晶粒同士のなす角を測定した場合に、小角粒界（０＜θ≦１５゜）の割合が５０％以上であるような結晶配列を示すＡｌとＴｉの複合窒化物層からなる硬質被覆層を蒸着形成することにより、高速断続切削条件においても硬質被覆層がすぐれた耐欠損性を発揮することが開示されている。
　ただ、この被覆工具は、物理蒸着法により硬質被覆層を蒸着形成するため、Ａｌの含有割合ｘを０．６５以上にすることは困難で、より一段と切削性能を向上させることが望まれている。 For example, Patent Document 1 discloses a composite nitridation of Al and Ti that satisfies the composition formula (Al x Ti 1-x ) N (wherein x is 0.40 to 0.65) in the tool base surface. When the crystal orientation analysis by EBSD is performed on the composite nitride layer made of a material layer, the area ratio of crystal grains having a crystal orientation <100> within a range of 0 to 15 degrees from the normal direction of the surface polished surface is 50 %, And when the angle between adjacent crystal grains is measured, the crystallographic arrangement in which the proportion of the small-angle grain boundaries (0 <θ ≦ 15 °) is 50% or more is made of Al and Ti. It is disclosed that by forming a hard coating layer made of a composite nitride layer by vapor deposition, the hard coating layer exhibits excellent fracture resistance even under high-speed intermittent cutting conditions.
However, since this coating tool forms a hard coating layer by physical vapor deposition, it is difficult to increase the Al content ratio x to 0.65 or more, and it is desired to further improve the cutting performance. .
　このような観点から、化学蒸着法で硬質被覆層を形成することで、Ａｌの含有割合ｘを、０．９程度にまで高める技術も提案されている。
　例えば、特許文献２には、ＴｉＣＮ層、Ａｌ２Ｏ３層を内層として、その上に、化学蒸着法により、立方晶構造あるいは六方晶構造を含む立方晶構造の（Ｔｉ１－ｘＡｌｘ）Ｎ層（ただし、原子比で、ｘは０．６５～０．９０）を外層として被覆するとともに該外層に１００～１１００ＭＰａの圧縮応力を付与することにより、被覆工具の耐熱性と疲労強度を改善することが提案されている。 From such a viewpoint, a technique for increasing the Al content ratio x to about 0.9 by forming a hard coating layer by a chemical vapor deposition method has also been proposed.
For example, in Patent Document 2, a TiCN layer and an Al 2 O 3 layer are used as inner layers, and a cubic structure or a hexagonal structure (Ti 1-x Al x ) including a cubic structure is formed thereon by chemical vapor deposition. Covering N layer (where x is 0.65 to 0.90 in atomic ratio) as an outer layer and applying compressive stress of 100 to 1100 MPa to the outer layer improves heat resistance and fatigue strength of the coated tool It has been proposed to do.
　また、例えば、特許文献３には、ＴｉＣｌ４、ＡｌＣｌ３、ＮＨ３の混合反応ガス中で、６５０～９００℃の温度範囲において化学蒸着を行うことにより、Ａｌの含有割合ｘの値が０．６５～０．９５である（Ｔｉ１－ｘＡｌｘ）Ｎ層を蒸着形成できることが記載されているが、この文献では、この（Ｔｉ１－ｘＡｌｘ）Ｎ層の上にさらにＡｌ２Ｏ３層を被覆し、これによって断熱効果を高めることを目的とするものであるから、Ａｌの含有割合ｘの値を０．６５～０．９５まで高めた（Ｔｉ１－ｘＡｌｘ）Ｎ層の形成によって、切削性能にどのような影響を及ぼしているかについては明らかでない。 Further, for example, in Patent Document 3, the value of the Al content ratio x is set to 0. 0 by performing chemical vapor deposition in a temperature range of 650 to 900 ° C. in a mixed reaction gas of TiCl 4 , AlCl 3 , and NH 3 . It is described that a (Ti 1-x Al x ) N layer having a thickness of 65 to 0.95 can be formed by vapor deposition. In this document, an Al 2 O layer is further formed on the (Ti 1-x Al x ) N layer. (Ti 1-x Al x ) N layer in which the value of the Al content ratio x is increased from 0.65 to 0.95 because the purpose is to cover three layers and thereby enhance the heat insulation effect. It is not clear what kind of influence the cutting performance has on the cutting performance.
　また、特許文献４には、組成式：（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）で表される複合窒化物または複合炭窒化物層(但し、原子比で、０．６０≦ｘ≦０．９５、０≦ｙ≦０．００５)を少なくとも含む硬質被覆層を被覆形成した被覆工具において、複合窒化物または複合炭窒化物層を構成する結晶粒は、立方晶構造と六方晶構造からなり、立方晶結晶相の占める面積割合を３０～８０面積％、立方晶構造を有する結晶粒の平均粒子幅Ｗを０．０５～１．０μｍ、平均アスペクト比を５以下とし、さらに、立方晶構造を有する結晶粒内に、ＴｉとＡｌの所定の周期の濃度変化を形成することによって、すぐれた硬さおよび靭性を備え、耐チッピング性、耐欠損性にもすぐれた被覆工具が提案されている。 Patent Document 4 discloses a composite nitride or composite carbonitride layer represented by the composition formula: (Ti 1-x Al x ) (C y N 1-y ) (provided that the atomic ratio is 0.60). ≦ x ≦ 0.95, 0 ≦ y ≦ 0.005) In a coated tool coated with a hard coating layer containing at least, the crystal grains constituting the composite nitride or the composite carbonitride layer have a cubic structure and hexagonal structure. The crystal structure has a cubic crystal phase with an area ratio of 30 to 80 area%, a crystal grain having a cubic crystal structure with an average particle width W of 0.05 to 1.0 μm, an average aspect ratio of 5 or less, and A coated tool with excellent hardness and toughness, chipping resistance and chipping resistance can be obtained by forming a concentration change of Ti and Al in a predetermined period in the crystal grains having a cubic structure. Proposed.
特開２００９－５６５４０号公報JP 2009-56540 A 特表２０１１－５１３５９４号公報Special table 2011-513594 gazette 特表２０１１－５１６７２２号公報Special table 2011-516722 gazette 特開２０１４－２１０３３３号公報JP 2014-210333 A
　近年の切削加工における省力化および省エネ化の要求は強く、これに伴い、切削加工は一段と高速化、高効率化の傾向にあり、被覆工具には、より一層、耐チッピング性、耐欠損性、耐剥離性等の耐異常損傷性が求められるとともに、長期の使用に亘ってのすぐれた耐摩耗性が求められている。
　しかし、前記特許文献１に記載されている被覆工具は、（Ｔｉ１－ｘＡｌｘ）Ｎ層からなる硬質被覆層が物理蒸着法で蒸着形成され、硬質被覆層中のＡｌの含有割合ｘを高めることが困難であるため、例えば、合金鋼、鋳鉄、ステンレス鋼等の高速断続切削に供した場合には、耐摩耗性、耐チッピング性が十分であるとは言えないという課題があった。
　一方、前記特許文献２に記載されている被覆工具は、所定の硬さを有し耐摩耗性にはすぐれるものの、靭性に劣ることから、合金鋼、鋳鉄、ステンレス鋼の高速断続切削加工等に供した場合には、チッピング、欠損、剥離等の異常損傷が発生しやすく、満足できる切削性能を発揮するとは言えないという課題があった。
　また、前記特許文献３に記載されている化学蒸着法で蒸着形成した（Ｔｉ１－ｘＡｌｘ）Ｎ層については、Ａｌの含有割合ｘを高めることができ、また、立方晶構造を形成させることができることから、所定の硬さを有し耐摩耗性にすぐれた硬質被覆層が得られるものの、工具基体との密着強度は十分でなく、また、靭性に劣るという課題があった。
　さらに、前記特許文献４に記載されている（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）で表される複合窒化物または複合炭窒化物層を蒸着形成した被覆工具は、層厚方向に沿って、前記立方晶構造を有する結晶粒内にＴｉとＡｌの周期的な濃度変化が存在することで立方晶結晶粒に歪みを生じさせ硬さを高め、また、特に層厚方向へのクラック進展を抑制し、その結果、耐チッピング性、耐欠損性が向上するが、切削時に摩耗が進行する面に作用するせん断力により生じる基体と平行な方向へのクラックの進展抑制は不十分であるという課題がある。
　そこで、本発明は、合金鋼、鋳鉄、ステンレス鋼等の高速断続切削等に供した場合であっても、すぐれた靭性を備え、長期の使用に亘ってすぐれた耐チッピング性、耐摩耗性を発揮する被覆工具を提供することを目的とする。 In recent years, there has been a strong demand for energy saving and energy saving in cutting, and along with this, cutting tends to be faster and more efficient, and the coated tool has even more chipping resistance, chipping resistance, Abnormal damage resistance such as peel resistance is required, and excellent wear resistance over long-term use is required.
However, in the coated tool described in Patent Document 1, a hard coating layer composed of a (Ti 1-x Al x ) N layer is deposited by physical vapor deposition, and the Al content ratio x in the hard coating layer is set. Since it is difficult to increase, for example, when subjected to high-speed intermittent cutting of alloy steel, cast iron, stainless steel, etc., there is a problem that it cannot be said that the wear resistance and chipping resistance are sufficient.
On the other hand, the coated tool described in Patent Document 2 has a predetermined hardness and excellent wear resistance, but is inferior in toughness. Therefore, high-speed intermittent cutting of alloy steel, cast iron, stainless steel, etc. In the case of being subjected to the above, there is a problem that abnormal damage such as chipping, chipping and peeling is likely to occur, and it cannot be said that satisfactory cutting performance is exhibited.
In addition, for the (Ti 1-x Al x ) N layer formed by chemical vapor deposition described in Patent Document 3, the Al content ratio x can be increased and a cubic structure can be formed. Therefore, although a hard coating layer having a predetermined hardness and excellent wear resistance can be obtained, there is a problem that the adhesion strength with the tool base is not sufficient and the toughness is inferior.
Further, the coated tool described in Patent Document 4 in which a composite nitride or composite carbonitride layer represented by (Ti 1-x Al x ) (C y N 1-y ) is formed by vapor deposition has a layer thickness. Along the direction, there is a periodic concentration change of Ti and Al in the crystal grains having the cubic structure, thereby causing distortion in the cubic crystal grains and increasing the hardness, and particularly in the layer thickness direction. As a result, chipping resistance and chipping resistance are improved, but crack growth in the direction parallel to the base caused by shearing force acting on the surface where wear progresses during cutting is insufficient. There is a problem of being.
Therefore, the present invention has excellent toughness and excellent chipping resistance and wear resistance over a long period of use even when subjected to high-speed intermittent cutting of alloy steel, cast iron, stainless steel, etc. It aims at providing the covering tool which exhibits.
　本発明者らは、前述の観点から、少なくともＴｉとＡｌの複合窒化物または複合炭窒化物（以下、「（Ｔｉ，Ａｌ）（Ｃ，Ｎ）」あるいは「（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）」で示すことがある）を含む硬質被覆層を化学蒸着で蒸着形成した被覆工具の耐チッピング性、耐摩耗性の改善をはかるべく、鋭意研究を重ねた結果、次のような知見を得た。 From the above viewpoint, the present inventors have at least a composite nitride or composite carbonitride of Ti and Al (hereinafter referred to as “(Ti, Al) (C, N)” or “(Ti 1-x Al x ) ( As a result of intensive research to improve the chipping resistance and wear resistance of the coated tool formed by chemical vapor deposition of the hard coating layer containing the material (which may be represented by C y N 1-y )) The following knowledge was obtained.
　即ち、本発明者らは、硬質被覆層を構成する（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）層の結晶粒内の濃度変化に着目し鋭意研究を進めたところ、（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）層の立方晶結晶構造を有する結晶粒粒内にＴｉとＡｌの周期的な濃度変化を形成させた場合に、刃先に高負荷が作用しても、剪断力に対する緩衝作用が生じ、これによって、クラックの進展が抑制されるとともに、（Ｔｉ，Ａｌ）（Ｃ，Ｎ）層の靭性が向上する。さらに、（Ｔｉ，Ａｌ）（Ｃ，Ｎ）層の層厚方向の熱伝導性が向上するため、切削加工時に高温となる刃先の硬度低下が抑えられ、その結果、耐摩耗性低下が抑制される。
　したがって、高速断続切削加工時の（Ｔｉ，Ａｌ）（Ｃ，Ｎ）層の耐チッピング性を向上させることができるという新規な知見を見出した。 That is, the inventors of the present invention have made extensive studies by paying attention to the concentration change in the crystal grains of the (Ti 1-x Al x ) (C y N 1-y ) layer constituting the hard coating layer. When a periodic concentration change of Ti and Al is formed in the crystal grains having the cubic crystal structure of the 1-x Al x ) (C y N 1-y ) layer, a high load acts on the cutting edge. However, a buffering action against a shearing force is generated, which suppresses the progress of cracks and improves the toughness of the (Ti, Al) (C, N) layer. Furthermore, since the thermal conductivity in the layer thickness direction of the (Ti, Al) (C, N) layer is improved, a decrease in hardness of the cutting edge that becomes a high temperature during cutting is suppressed, and as a result, a decrease in wear resistance is suppressed. The
Therefore, the present inventors have found a novel finding that the chipping resistance of the (Ti, Al) (C, N) layer during high-speed intermittent cutting can be improved.
　具体的には、硬質被覆層が、ＴｉとＡｌの複合窒化物または複合炭窒化物層を少なくとも含み、組成式：（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）で表した場合、ＡｌのＴｉとＡｌの合量に占める平均含有割合ＸａｖｇおよびＣのＣとＮの合量に占める平均含有割合Ｙａｖｇ（但し、Ｘａｖｇ、Ｙａｖｇはいずれも原子比）が、それぞれ、０．４０≦Ｘａｖｇ≦０．９５、０≦Ｙａｖｇ≦０．００５を満足し、複合窒化物または複合炭窒化物層を構成する結晶粒中にＮａＣｌ型の面心立方構造を有するものが存在し、また、前記ＮａＣｌ型の面心立方構造を有する結晶粒内には、組成式：（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）におけるＴｉとＡｌの周期的な濃度変化が存在し、かつ、該周期的な濃度変化の方向は、工具基体表面に平行な面となす角度が３０度以内の方向であり、また、好ましくは、該周期的な濃度変化の周期は１～１０ｎｍであり、周期的に変化するＡｌの含有割合ｘの極大値と極小値の差は０．０１～０．１であることによって、切削加工時に加わる剪断力に対しての緩衝作用が生じ、その結果、クラックの進展が抑制され、耐チッピング性、耐欠損性が向上し、長期に亘ってすぐれた切削性能を発揮することを見出した。 Specifically, when the hard coating layer includes at least a composite nitride or composite carbonitride layer of Ti and Al, and is represented by a composition formula: (Ti 1-x Al x ) (C y N 1-y ) , The average content ratio X avg in the total amount of Ti and Al in Al and the average content ratio Y avg in the total amount of C and N in C (where X avg and Y avg are atomic ratios), respectively, Those satisfying 0.40 ≦ X avg ≦ 0.95 and 0 ≦ Y avg ≦ 0.005 and having a NaCl-type face-centered cubic structure in the crystal grains constituting the composite nitride or composite carbonitride layer In addition, in the crystal grains having the NaCl type face-centered cubic structure, periodic concentration changes of Ti and Al in the composition formula: (Ti 1-x Al x ) (C y N 1-y ) And the direction of the periodic concentration change depends on the tool base. The angle formed by a plane parallel to the surface is within a direction of 30 degrees, and preferably the period of the periodic concentration change is 1 to 10 nm, and the Al content ratio x varies periodically. And the minimum value between 0.01 and 0.1 creates a buffering action against the shearing force applied during the cutting process. As a result, the progress of cracks is suppressed, and the chipping resistance and chipping resistance are reduced. And improved cutting performance was demonstrated over a long period of time.
　そして、前述のような構成の（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）層は、例えば、工具基体表面において反応ガス組成を周期的に変化させる以下の化学蒸着法によって成膜することができる。
　用いる化学蒸着反応装置へは、ＮＨ３とＨ２からなるガス群Ａと、ＴｉＣｌ４、ＡｌＣｌ３、Ｎ２、Ｃ２Ｈ４、Ｈ２からなるガス群Ｂがおのおの別々のガス供給管から反応装置内へ供給され、ガス群Ａとガス群Ｂの反応装置内への供給は、例えば、一定の周期の時間間隔で、その周期よりも短い時間だけガスが流れるように供給し、ガス群Ａとガス群Ｂのガス供給にはガス供給時間よりも短い時間の位相差が生じるようにして、工具基体表面における反応ガス組成を、（イ）ガス群Ａ、（ロ）ガス群Ａとガス群Ｂの混合ガス、（ハ）ガス群Ｂと時間的に変化させることができる。ちなみに、本発明においては、厳密なガス置換を意図した長時間の排気工程を導入する必要は無い。従って、ガス供給方法としては、例えば、ガス供給口を回転させたり、工具基体を回転させたり、工具基体を往復運動させたりして、工具基体表面における反応ガス組成を、（イ）ガス群Ａを主とする混合ガス、（ロ）ガス群Ａとガス群Ｂの混合ガス、（ハ）ガス群Ｂを主とする混合ガス、と時間的に変化させることで実現する事が可能である。
　即ち、工具基体表面に、反応ガス組成（ガス群Ａおよびガス群Ｂを合わせた全体に対する容量％）を、例えば、ガス群ＡとしてＮＨ３：１．０～２．５％、Ｈ２：６０～７５％、ガス群ＢとしてＡｌＣｌ３：０．１０～０．９０％、ＴｉＣｌ４：０．１０～０．３０％、Ｎ２：０．０～１２．０％、Ｃ２Ｈ４：０～０．５％、Ｈ２：残とし、さらに、反応雰囲気圧力：４．５～５．０ｋＰａ、反応雰囲気温度：７００～８００℃、供給周期１～２秒、１周期当たりのガス供給時間０．０５～０．１２秒、ガス群Ａの供給とガス群Ｂの供給の位相差０．０４～０．０９秒として、所定時間、熱ＣＶＤ法を行うことにより、前記所定の（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）層を成膜することができる。 The (Ti 1-x Al x ) (C y N 1-y ) layer having the above-described configuration is formed by, for example, the following chemical vapor deposition method that periodically changes the reaction gas composition on the tool base surface. can do.
In the chemical vapor deposition reactor to be used, a gas group A composed of NH 3 and H 2 and a gas group B composed of TiCl 4 , AlCl 3 , N 2 , C 2 H 4 , and H 2 react from respective separate gas supply pipes. The gas group A and the gas group B are supplied into the reaction apparatus, for example, in such a manner that the gas flows for a time shorter than the period at a constant time interval. In the gas supply of the gas group B, a phase difference of a time shorter than the gas supply time is generated, and the reaction gas composition on the tool base surface is set to (i) gas group A, (b) gas group A and gas group. The mixed gas of B and (c) the gas group B can be changed with time. Incidentally, in the present invention, it is not necessary to introduce a long exhaust process intended for strict gas replacement. Therefore, as the gas supply method, for example, the gas supply port is rotated, the tool base is rotated, or the tool base is reciprocated to change the reaction gas composition on the tool base surface. This can be realized by changing the mixture gas in time, (b) the mixed gas of the gas group A and the gas group B, and (c) the mixed gas mainly of the gas group B.
That is, the reaction gas composition (volume% with respect to the total of the gas group A and the gas group B) on the surface of the tool base is, for example, NH 3 : 1.0 to 2.5% as the gas group A, H 2 : 60. -75%, gas group B as AlCl 3 : 0.10 to 0.90%, TiCl 4 : 0.10 to 0.30%, N 2 : 0.0 to 12.0%, C 2 H 4 : 0 ~ 0.5%, H 2 : the rest, further, reaction atmosphere pressure: 4.5 to 5.0 kPa, reaction atmosphere temperature: 700 to 800 ° C, supply period 1 to 2 seconds, gas supply time per period 0 .05 to 0.12 seconds, the phase difference between the supply of the gas group A and the supply of the gas group B is 0.04 to 0.09 seconds, and the predetermined (Ti 1− An x Al x ) (C y N 1-y ) layer can be deposited.
　前述のようにガス群Ａとガス群Ｂが工具基体表面に到達する時間に差が生じるように供給する事により、結晶粒内にＴｉとＡｌの局所的な濃度差が形成され、その結果、特に、耐チッピング性、耐欠損性が向上し、切れ刃に断続的・衝撃的負荷が作用する合金鋼、鋳鉄、ステンレス鋼等の高速断続切削加工に用いた場合においても、硬質被覆層が、長期の使用に亘ってすぐれた耐摩耗性を発揮し得ることを見出した。 As described above, by supplying the gas group A and the gas group B so as to cause a difference in the time required to reach the tool base surface, a local concentration difference between Ti and Al is formed in the crystal grains, and as a result, In particular, even when used for high-speed intermittent cutting of alloy steel, cast iron, stainless steel, etc., where the chipping resistance and fracture resistance are improved and intermittent and impact loads are applied to the cutting edge, the hard coating layer is It has been found that excellent wear resistance can be exhibited over a long period of use.
　本発明は、前記知見に基づいてなされたものであって、
「（１）　炭化タングステン基超硬合金、炭窒化チタン基サーメットまたは立方晶窒化ホウ素基超高圧焼結体のいずれかで構成された工具基体の表面に、硬質被覆層が設けられた表面被覆切削工具において、
（ａ）前記硬質被覆層は、平均層厚１～２０μｍのＴｉとＡｌの複合窒化物または複合炭窒化物層を少なくとも含み、
（ｂ）前記複合窒化物または複合炭窒化物層は、ＮａＣｌ型の面心立方構造を有する複合窒化物または複合炭窒化物の結晶粒を少なくとも含み、
（ｃ）前記複合窒化物または複合炭窒化物層を、工具基体の表面と垂直な任意の断面から分析した場合、前記ＮａＣｌ型の面心立方構造を有する結晶粒内には、ＴｉとＡｌの周期的な濃度変化が存在し、該ＴｉとＡｌの周期的な濃度変化のうちで濃度変化の周期が最小になる方向を求めたとき、該濃度変化の周期が最小になる方向と工具基体表面とのなす角が３０度以内であるようなＮａＣｌ型の面心立方構造を有する結晶粒が少なくとも存在することを特徴とする表面被覆切削工具。
（２）　前記複合窒化物または複合炭窒化物層は、その組成を、
　組成式：（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）
　で表した場合、ＡｌのＴｉとＡｌの合量に占める平均含有割合ＸａｖｇおよびＣのＣとＮの合量に占める平均含有割合Ｙａｖｇ（但し、Ｘａｖｇ、Ｙａｖｇはいずれも原子比）が、それぞれ、０．４０≦Ｘａｖｇ≦０．９５、０≦Ｙａｖｇ≦０．００５を満足であることを特徴とする（１）に記載の表面被覆切削工具。
（３）　前記複合窒化物または複合炭窒化物層の前記断面からの観察において、前記ＴｉとＡｌの周期的な濃度変化が存在し、かつ、ＴｉとＡｌの周期的な濃度変化のうちで濃度変化の周期が最小になる方向と工具基体表面とのなす角が３０度以内であるようなＮａＣｌ型の面心立方構造を有する結晶粒が、前記複合窒化物または複合炭窒化物層の面積に占める割合は、４０面積％以上であることを特徴とする（１）または（２）に記載の表面被覆切削工具。
（４）　前記複合窒化物または複合炭窒化物層中のＴｉとＡｌの周期的な濃度変化が存在し、かつ、ＴｉとＡｌの周期的な濃度変化のうちで濃度変化の周期が最小になる方向と工具基体表面とのなす角が３０度以内であるようなＮａＣｌ型の面心立方構造を有する結晶粒において、ＴｉとＡｌの周期的な濃度変化の周期は１～１０ｎｍであり、かつ、周期的に変化するＡｌの含有割合ｘの極大値の平均と極小値の平均の差は０．０１～０．１であることを特徴とする（１）～（３）のいずれかに記載の表面被覆切削工具。
（５）　前記複合窒化物または複合炭窒化物層について、該層の前記断面方向から観察した場合に、複合窒化物または複合炭窒化物層内のＮａＣｌ型の面心立方構造を有する個々の結晶粒の粒界部に、六方晶構造を有する微粒結晶粒が存在し、該微粒結晶粒の存在する面積割合が５面積％以下であり、該微粒結晶粒の平均粒径Ｒが０．０１～０．３μｍであることを特徴とする（１）～（４）のいずれかに記載の表面被覆切削工具。
（６）　前記工具基体と前記ＴｉとＡｌの複合窒化物または複合炭窒化物層の間に、Ｔｉの炭化物層、窒化物層、炭窒化物層、炭酸化物層および炭窒酸化物層のうちの１層または２層以上のＴｉ化合物層からなり、０．１～２０μｍの合計平均層厚を有する下部層が存在することを特徴とする（１）～（５）のいずれかに記載の表面被覆切削工具。
（７）　前記複合窒化物または複合炭窒化物層の上部に、少なくとも酸化アルミニウム層を含む上部層が１～２５μｍの合計平均層厚で形成されていることを特徴とする（１）～（６）のいずれかに記載の表面被覆切削工具。」
に特徴を有するものである。 The present invention has been made based on the above findings,
“(1) Surface-coated cutting in which a hard coating layer is provided on the surface of a tool base made of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, or cubic boron nitride-based ultrahigh-pressure sintered body In the tool
(A) The hard coating layer includes at least a composite nitride or composite carbonitride layer of Ti and Al having an average layer thickness of 1 to 20 μm,
(B) The composite nitride or composite carbonitride layer includes at least crystal grains of composite nitride or composite carbonitride having a NaCl type face-centered cubic structure,
(C) When the composite nitride or composite carbonitride layer is analyzed from an arbitrary cross section perpendicular to the surface of the tool base, the crystal grains having the NaCl-type face-centered cubic structure include Ti and Al. When there is a periodic concentration change, and the direction in which the concentration change cycle is minimized among the periodic concentration changes of Ti and Al, the direction in which the concentration change cycle is minimized and the tool base surface A surface-coated cutting tool characterized in that at least crystal grains having an NaCl-type face-centered cubic structure with an angle of 30 degrees or less are present.
(2) The composite nitride or composite carbonitride layer has the composition
Composition formula: (Ti 1-x Al x ) (C y N 1-y )
The average content ratio X avg in the total amount of Ti and Al in Al and the average content ratio Y avg in the total amount of C and N in C (where X avg and Y avg are both atomic ratios) Satisfying 0.40 ≦ X avg ≦ 0.95 and 0 ≦ Y avg ≦ 0.005, respectively, the surface-coated cutting tool according to (1).
(3) In the observation of the composite nitride or composite carbonitride layer from the cross section, there is a periodic concentration change of Ti and Al, and the concentration of the periodic concentration changes of Ti and Al. Crystal grains having a NaCl-type face-centered cubic structure in which the angle formed between the direction in which the period of change is minimized and the surface of the tool substrate is within 30 degrees are included in the area of the composite nitride or composite carbonitride layer. The surface-coated cutting tool according to (1) or (2), characterized in that an occupying ratio is 40 area% or more.
(4) There is a periodic concentration change of Ti and Al in the composite nitride or composite carbonitride layer, and the cycle of concentration change is minimized among the periodic concentration changes of Ti and Al. In a crystal grain having a NaCl-type face-centered cubic structure in which the angle between the direction and the tool substrate surface is within 30 degrees, the period of periodic concentration change of Ti and Al is 1 to 10 nm, and The difference between the average of the maximum value and the average of the minimum value of the Al content ratio x, which changes periodically, is 0.01 to 0.1, according to any one of (1) to (3), Surface coated cutting tool.
(5) When the composite nitride or composite carbonitride layer is observed from the cross-sectional direction of the layer, individual crystals having a NaCl-type face-centered cubic structure in the composite nitride or composite carbonitride layer There are fine crystal grains having a hexagonal crystal structure in the grain boundary portion, the area ratio of the fine crystal grains is 5 area% or less, and the average grain size R of the fine crystal grains is 0.01 to The surface-coated cutting tool according to any one of (1) to (4), wherein the surface-coated cutting tool is 0.3 μm.
(6) Ti carbide layer, nitride layer, carbonitride layer, carbonate layer, and carbonitride oxide layer between the tool base and the composite nitride or composite carbonitride layer of Ti and Al The surface according to any one of (1) to (5), wherein there is a lower layer having a total average layer thickness of 0.1 to 20 μm. Coated cutting tool.
(7) An upper layer including at least an aluminum oxide layer is formed on the composite nitride or composite carbonitride layer with a total average layer thickness of 1 to 25 μm. (1) to (6) The surface-coated cutting tool according to any one of 1). "
It has the characteristics.
　本発明について、以下に詳細に説明する。 The present invention will be described in detail below.
ＴｉとＡｌの複合窒化物または複合炭窒化物層の平均層厚：
　図１に、本発明の硬質被覆層を構成するＴｉとＡｌの複合窒化物または複合炭窒化物層の断面模式図を示す。
　本発明の硬質被覆層は、組成式：（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）で表されるＴｉとＡｌの複合窒化物または複合炭窒化物層を少なくとも含む。この複合窒化物または複合炭窒化物層は、硬さが高く、すぐれた耐摩耗性を有するが、特に平均層厚が１～２０μｍのとき、その効果が際立って発揮される。その理由は、平均層厚が１μｍ未満では、層厚が薄いため長期の使用に亘っての耐摩耗性を十分確保することができず、一方、その平均層厚が２０μｍを越えると、ＴｉとＡｌの複合窒化物または複合炭窒化物層の結晶粒が粗大化し易くなり、チッピングを発生しやすくなる。したがって、その平均層厚を１～２０μｍと定めた。 Average layer thickness of composite nitride or composite carbonitride layer of Ti and Al:
In FIG. 1, the cross-sectional schematic diagram of the composite nitride or composite carbonitride layer of Ti and Al which comprises the hard coating layer of this invention is shown.
The hard coating layer of the present invention includes at least a composite nitride or composite carbonitride layer of Ti and Al represented by a composition formula: (Ti 1-x Al x ) (C y N 1-y ). This composite nitride or composite carbonitride layer has high hardness and excellent wear resistance, but the effect is particularly remarkable when the average layer thickness is 1 to 20 μm. The reason is that if the average layer thickness is less than 1 μm, the layer thickness is so thin that sufficient wear resistance over a long period of use cannot be ensured. On the other hand, if the average layer thickness exceeds 20 μm, Ti and Crystal grains of the Al composite nitride or composite carbonitride layer are likely to be coarsened, and chipping is likely to occur. Therefore, the average layer thickness is set to 1 to 20 μm.
ＴｉとＡｌの複合窒化物または複合炭窒化物層の組成：
　本発明の硬質被覆層を構成する複合窒化物または複合炭窒化物層は、ＡｌのＴｉとＡｌの合量に占める平均含有割合ＸａｖｇおよびＣのＣとＮの合量に占める平均含有割合Ｙａｖｇ（但し、Ｘａｖｇ、Ｙａｖｇはいずれも原子比）が、それぞれ、０．４０≦Ｘａｖｇ≦０．９５、０≦Ｙａｖｇ≦０．００５を満足するように制御することが望ましい。
　その理由は、Ａｌの平均含有割合Ｘａｖｇが０．４０未満であると、ＴｉとＡｌの複合窒化物または複合炭窒化物層は耐酸化性に劣るため、合金鋼、鋳鉄、ステンレス鋼等の高速断続切削に供した場合には、耐摩耗性が十分でない。一方、Ａｌの平均含有割合Ｘａｖｇが０．９５を超えると、硬さに劣る六方晶の析出量が増大し硬さが低下するため、耐摩耗性が低下する。したがって、Ａｌの平均含有割合Ｘａｖｇは、０．４０≦Ｘａｖｇ≦０．９５とすることが望ましい。
　また、複合窒化物または複合炭窒化物層に含まれるＣ成分の平均含有割合Ｙａｖｇは、０≦Ｙａｖｇ≦０．００５の範囲の微量であるとき、複合窒化物または複合炭窒化物層と工具基体もしくは下部層との密着性が向上し、かつ、潤滑性が向上することによって切削時の衝撃を緩和し、結果として複合窒化物または複合炭窒化物層の耐欠損性および耐チッピング性が向上する。一方、Ｃ成分の平均含有割合Ｙａｖｇが０≦Ｙａｖｇ≦０．００５の範囲を外れると、複合窒化物または複合炭窒化物層の靭性が低下し、耐欠損性および耐チッピング性が低下するため好ましくない。したがって、Ｃの平均含有割合Ｙａｖｇは、０≦Ｙａｖｇ≦０．００５とすることが望ましい。
　ただし、Ｃの含有割合Ｙａｖｇについては、ガス原料としてＣを含むガスを用いなくても不可避的に含有されるＣの含有割合を除外している。具体的には、例えば、Ｃを含むガス原料であるＣ２Ｈ４の供給量を０とした場合に、複合窒化物または複合炭窒化物層に含まれるＣ成分の含有割合（原子比）を不可避的なＣの含有割合として求め、例えば、Ｃ２Ｈ４を意図的に供給した場合に得られる複合窒化物または複合炭窒化物層に含まれるＣ成分の含有割合（原子比）から前記不可避的に含有されるＣの含有割合を差し引いた値をＹａｖｇとして定めた。 Composition of Ti and Al composite nitride or composite carbonitride layer:
The composite nitride or composite carbonitride layer constituting the hard coating layer of the present invention has an average content ratio X avg in the total amount of Ti and Al in Al and an average content ratio Y in the total amount of C and N in C It is desirable to control so that avg (where X avg and Y avg are both atomic ratios) satisfy 0.40 ≦ X avg ≦ 0.95 and 0 ≦ Y avg ≦ 0.005, respectively.
The reason for this is that when the average content ratio X avg of Al is less than 0.40, the composite nitride or composite carbonitride layer of Ti and Al is inferior in oxidation resistance, so alloy steel, cast iron, stainless steel, etc. When subjected to high-speed intermittent cutting, the wear resistance is not sufficient. On the other hand, when the average content ratio X avg of Al exceeds 0.95, the precipitation amount of hexagonal crystals inferior in hardness increases and the hardness decreases, so that the wear resistance decreases. Therefore, it is desirable that the average content ratio X avg of Al is 0.40 ≦ X avg ≦ 0.95.
Further, when the average content ratio Y avg of the C component contained in the composite nitride or the composite carbonitride layer is a minute amount in the range of 0 ≦ Y avg ≦ 0.005, the composite nitride or the composite carbonitride layer The adhesion with the tool base or the lower layer is improved, and the lubrication improves the impact during cutting. As a result, the chipping resistance and chipping resistance of the composite nitride or composite carbonitride layer are reduced. improves. On the other hand, when the average content ratio Y avg of the component C is out of the range of 0 ≦ Y avg ≦ 0.005, the toughness of the composite nitride or composite carbonitride layer is lowered, and the chipping resistance and chipping resistance are lowered. Therefore, it is not preferable. Therefore, the average content ratio Y avg of C is preferably 0 ≦ Y avg ≦ 0.005.
However, the C content ratio Y avg excludes the C content ratio inevitably contained without using a gas containing C as a gas raw material. Specifically, for example, when the supply amount of C 2 H 4 which is a gas raw material containing C is 0, the content ratio (atomic ratio) of the C component contained in the composite nitride or composite carbonitride layer is set to As an inevitable content ratio of C, for example, from the content ratio (atomic ratio) of the C component contained in the composite nitride or composite carbonitride layer obtained when C 2 H 4 is intentionally supplied, the inevitable A value obtained by subtracting the content ratio of C contained was determined as Y avg .
周期的な濃度変化：
　図２、図３の模式図に示すように、前記複合窒化物または複合炭窒化物層のＮａＣｌ型の面心立方構造を有する結晶粒内には、ＴｉとＡｌの周期的な濃度変化が存在するが、周期的な濃度変化の方向が、工具基体表面に平行な面となす角度が３０度以内の方向であるようなＮａＣｌ型の面心立方構造を有する結晶粒が少なくとも存在することが必要である。
　前記でいう「周期的な濃度変化の方向が、工具基体表面に平行な面となす角度が３０度以内の方向である」とは、「硬質被覆層を構成する複合窒化物または複合炭窒化物層を、工具基体の表面と垂直な任意の断面から分析した場合、ＮａＣｌ型の面心立方構造を有する結晶粒内に存在するＴｉとＡｌの周期的な濃度変化のうちで、濃度変化の周期が最小になる方向を求め、該濃度変化の周期が最小になる方向と工具基体表面に平行な面となす角が３０度以内であるような周期的な濃度変化の方向」（以下、「本発明濃度変化の方向」と略記する。）のことである。
　ここで、該周期的な濃度変化の方向が、工具基体表面に平行な面となす角度が３０度以内の方向であるＮａＣｌ型の面心立方構造を有する結晶粒が少なくとも存在することが必要である理由は、次のとおりである。
　本発明の成膜では、反応ガス群Ａとガス群Ｂが工具基体表面に到達する時間に差が生じるように供給する事により、結晶粒内にＴｉとＡｌの局所的な濃度差が形成され、特に、原料ガスが工具基体表面に供給される周期の時間間隔が短く、１周期当たりの成膜量が少なくなる場合において、ＡｌとＴｉ原子の表面拡散、再配列よって、周期的な濃度変化の方向が工具基体表面に平行な面となす角度が３０度以内の方向として安定化する。
　前記工具基体表面に平行な面となす角度が３０度以内の方向の周期的な濃度変化は、切削時に摩耗が進行する面に作用するせん断力により生じる基体と平行な方向へのクラックの進展を抑制し、靭性が向上するが、周期的な濃度変化の方向が、工具基体表面に平行な面となす角度が３０度を超えると、基体と平行な方向へのクラックの進展を抑制する効果が見込めず、靭性向上の効果も見込めない。このクラック進展抑制効果については、ＴｉとＡｌの濃度の異なる境界において、その進展方向の曲がりや屈折が生じることにより発揮されるものと推測される。
　したがって、本発明では、結晶粒内における周期的な濃度変化の方向が、工具基体表面に平行な面となす角度が３０度以内の方向であるＮａＣｌ型の面心立方構造を有する結晶粒が存在することが必要である。 Periodic concentration change:
As shown in the schematic diagrams of FIGS. 2 and 3, periodic concentration changes of Ti and Al exist in the crystal grains having the NaCl-type face-centered cubic structure of the composite nitride or composite carbonitride layer. However, it is necessary that at least crystal grains having a NaCl-type face-centered cubic structure in which the direction of periodic concentration change is a direction within 30 degrees with respect to a plane parallel to the tool base surface. It is.
The above-mentioned “the direction of the periodic concentration change is a direction within 30 degrees with respect to the plane parallel to the tool substrate surface” means “the composite nitride or the composite carbonitride constituting the hard coating layer” When the layer is analyzed from an arbitrary cross section perpendicular to the surface of the tool substrate, among the periodic concentration changes of Ti and Al existing in the crystal grains having the NaCl type face-centered cubic structure, the concentration change period The direction in which the density change period is minimized, and the direction in which the angle between the direction in which the density change period is minimum and the plane parallel to the surface of the tool substrate is within 30 degrees is referred to as It is abbreviated as “direction of concentration change of the invention”).
Here, it is necessary that at least crystal grains having a NaCl-type face-centered cubic structure in which the direction of the periodic concentration change is within 30 degrees with respect to a plane parallel to the tool base surface. The reason is as follows.
In the film formation of the present invention, a local concentration difference between Ti and Al is formed in the crystal grains by supplying the reaction gas group A and the gas group B so that there is a difference in the time required to reach the tool base surface. In particular, when the time interval of the cycle in which the source gas is supplied to the tool base surface is short, and the amount of film formation per cycle is small, the concentration change periodically due to surface diffusion and rearrangement of Al and Ti atoms. Is stabilized as a direction within 30 degrees with respect to a direction parallel to the surface of the tool base.
The periodic concentration change in the direction within 30 degrees with the surface parallel to the surface of the tool base causes the development of cracks in the direction parallel to the base caused by the shearing force acting on the surface where wear proceeds during cutting. Suppresses and improves toughness, but if the angle between the periodic concentration change direction and the plane parallel to the surface of the tool base exceeds 30 degrees, the effect of suppressing the progress of cracks in the direction parallel to the base is effective. It cannot be expected, and the effect of improving toughness cannot be expected. This crack progress suppressing effect is presumed to be exhibited by bending or refraction in the progress direction at the boundaries where the concentrations of Ti and Al differ.
Therefore, in the present invention, there is a crystal grain having a NaCl-type face-centered cubic structure in which the direction of periodic concentration change in the crystal grain is a direction within 30 degrees with respect to a plane parallel to the tool substrate surface. It is necessary to.
　本発明の硬質皮膜層を構成する複合窒化物または複合炭窒化物層の任意の断面からの観察において、本発明濃度変化の方向を有するＮａＣｌ型の面心立方構造を有する結晶粒が、複合窒化物または複合炭窒化物層の面積に占める割合は４０面積％以上であることが望ましい。
　その理由は、複合窒化物または複合炭窒化物層の面積に占める本発明濃度変化の方向を有するＮａＣｌ型の面心立方構造を有する結晶粒の割合が４０面積％未満であると切削時に摩耗が進行する面に作用するせん断力により生じる基体と平行な方向へのクラック進展を十分抑制することができず、また、靭性を向上させる効果も十分でないからである。
　また、本発明の硬質皮膜層を構成する複合窒化物または複合炭窒化物層は、柱状組織を有することが好ましいが、これは、柱状組織が優れた耐摩耗性を示し、本発明の硬質被膜層（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）層では、柱状組織の立方晶の粒界中に六方晶構造の微粒結晶粒を含有することができるが、柱状組織の立方晶粒界に靱性に優れた微粒六方晶が存在することで粒界における摩擦が低減し、靱性が向上するという理由による。
　本発明濃度変化の方向を有する結晶粒の面積割合の算出は、透過型電子顕微鏡を用いて、１μｍ×１μｍの像におけるＴｉとＡｌの周期的な濃度変化に対応する画像のコントラストの変化、あるいはエネルギー分散型Ｘ線分光法（ＥＤＳ）によって確認されるＴｉとＡｌの周期的な濃度変化を有する領域から、各結晶粒の濃度変化の方向を求め、これらの中から、周期的濃度変化の方向が工具基体表面となす角が３０度以内である結晶粒（即ち、本発明濃度変化の方向を有する結晶粒）を抽出し、これらの結晶粒の面積をそれぞれ算出し、前記１μｍ×１μｍの観察領域に占める面積割合を少なくとも１０視野で行い、その平均値を本発明濃度変化の方向を有する結晶粒の面積として求めることが出来る。 In observation of the composite nitride or composite carbonitride layer constituting the hard coating layer of the present invention from an arbitrary cross-section, the crystal grains having the NaCl type face-centered cubic structure having the direction of concentration change of the present invention are complex nitride. The proportion of the product or the composite carbonitride layer in the area is preferably 40% by area or more.
The reason for this is that when the proportion of crystal grains having a NaCl-type face-centered cubic structure having the direction of concentration change of the present invention occupying the area of the composite nitride or composite carbonitride layer is less than 40 area%, wear occurs during cutting. This is because the crack propagation in the direction parallel to the base caused by the shearing force acting on the traveling surface cannot be sufficiently suppressed, and the effect of improving toughness is not sufficient.
Further, the composite nitride or composite carbonitride layer constituting the hard coating layer of the present invention preferably has a columnar structure. This indicates that the columnar structure exhibits excellent wear resistance, and the hard coating of the present invention. In the layer (Ti 1-x Al x ) (C y N 1-y ) layer, fine crystal grains having a hexagonal structure can be contained in the cubic grain boundaries of the columnar structure. This is because the presence of fine hexagonal crystals having excellent toughness at the grain boundaries reduces friction at the grain boundaries and improves toughness.
The calculation of the area ratio of the crystal grains having the direction of density change according to the present invention can be performed by using a transmission electron microscope to change the contrast of an image corresponding to a periodic density change of Ti and Al in a 1 μm × 1 μm image, or The direction of the concentration change of each crystal grain is obtained from the region having the periodic concentration change of Ti and Al confirmed by energy dispersive X-ray spectroscopy (EDS), and from these, the direction of the periodic concentration change is determined. Extract crystal grains whose angle with the tool base surface is within 30 degrees (ie, crystal grains having the direction of concentration change of the present invention), calculate the area of each of these crystal grains, and observe 1 μm × 1 μm. The area ratio in the region can be determined in at least 10 fields of view, and the average value can be obtained as the area of the crystal grains having the direction of concentration change of the present invention.
　さらに、本発明濃度変化の方向を有する結晶粒は、濃度変化の周期は１～１０ｎｍであり、また、周期的に変化するＡｌの含有割合ｘの極大値の平均と極小値の平均の差は０．０１～０．１であることが望ましい。
　これは、濃度変化の周期が１ｎｍ未満であると、結晶粒の歪みが大きくなり過ぎ、格子欠陥が多くなり、硬さが低下し、一方、濃度変化の周期が１０ｎｍを超えると、切削時に摩耗が進行する面に作用するせん断力により生じる基体と平行な方向へのクラックの進展を抑制し、靱性を向上させる十分な緩衝作用が見込めず、濃度変化の周期は１～１０ｎｍとすることが望ましい。
　また、前記結晶粒内にＴｉとＡｌの周期的な濃度変化が存在することによって、結晶粒に歪みが生じ、硬さが向上するが、ＴｉとＡｌの周期的な濃度変化量の大きさの指標であるＡｌの含有割合ｘの極大値の平均と極小値の平均の差Δｘが０．０１より小さいと結晶粒の歪みが小さく十分な硬さの向上が見込めず、一方、ｘの極大値の平均と極小値の平均の差Δｘが０．１を超えると結晶粒の歪みが大きくなり過ぎ、格子欠陥が増加し硬さが低下するという理由による。
　そこで、ＮａＣｌ型の面心立方構造を有する結晶粒内に存在するＴｉとＡｌの周期的濃度変化について、周期的に変化するＡｌの含有割合ｘの極大値の平均と極小値の平均の差Δｘを０．０１～０．１とすることが望ましい。
図４には、結晶粒内に存在するＴｉとＡｌの周期的な濃度変化の様子を、透過型電子顕微鏡を用いて、エネルギー分散型Ｘ線分光法（ＥＤＳ）による線分析を行って求めたＴｉとＡｌの周期的な濃度変化を示すグラフの一例を示す。
　なお、図４における周期的な濃度変化の方向は、工具基体表面に平行な面となす角度が０度の方向（即ち、工具基体表面と平行な方向）の例である。 Furthermore, the crystal grains having the direction of concentration change of the present invention have a concentration change period of 1 to 10 nm, and the difference between the average of the maximum value and the average of the minimum value of the Al content ratio x that changes periodically is It is desirable that it is 0.01 to 0.1.
This is because if the period of concentration change is less than 1 nm, the distortion of crystal grains becomes too large, the number of lattice defects increases, and the hardness decreases. On the other hand, if the period of concentration change exceeds 10 nm, wear occurs during cutting. It is desirable to suppress the growth of cracks in the direction parallel to the base caused by the shearing force acting on the surface where the metal proceeds, and a sufficient buffering action to improve toughness cannot be expected, and the concentration change period is preferably 1 to 10 nm. .
Further, the presence of a periodic concentration change of Ti and Al in the crystal grains causes distortion in the crystal grains and improves the hardness, but the magnitude of the periodic concentration change amount of Ti and Al increases. If the difference Δx between the average of the maximum value and the minimum value of the Al content ratio x as an index is smaller than 0.01, the distortion of the crystal grains is small and sufficient hardness cannot be expected, while the maximum value of x This is because if the difference Δx between the average and the minimum value exceeds 0.1, the distortion of the crystal grains becomes too large, the lattice defects increase, and the hardness decreases.
Therefore, regarding the periodic concentration change of Ti and Al present in the crystal grains having the NaCl type face-centered cubic structure, the difference Δx between the average of the maximum value and the average of the minimum value of the periodically changing Al content ratio x. Is preferably 0.01 to 0.1.
In FIG. 4, the state of periodic concentration changes of Ti and Al present in the crystal grains was obtained by performing line analysis by energy dispersive X-ray spectroscopy (EDS) using a transmission electron microscope. An example of the graph which shows the periodic density | concentration change of Ti and Al is shown.
Note that the direction of periodic density change in FIG. 4 is an example of a direction in which an angle formed with a plane parallel to the tool base surface is 0 degrees (ie, a direction parallel to the tool base surface).
ＴｉとＡｌの複合窒化物または複合炭窒化物層中に存在する微粒六方晶結晶粒：
　本発明のＴｉとＡｌの複合窒化物または複合炭窒化物層では、ＮａＣｌ型の面心立方構造を有する結晶粒の粒界に六方晶構造の微粒結晶粒を含有することができる。
　硬さにすぐれたＮａＣｌ型の面心立方構造を有する結晶粒の粒界に、微粒六方晶が存在することで粒界すべりが抑えられ、ＴｉとＡｌの複合窒化物または複合炭窒化物層の靱性が向上する。しかし、六方晶構造の微粒結晶粒の面積割合が５面積％を超えると相対的に硬さが低下し好ましくなく、また、六方晶構造の微粒結晶粒の平均粒径Ｒが０．０１μｍ未満であると粒界滑りを抑制する効果が十分でなく、一方、０．３μｍを超えると層内の歪みが大きくなり硬さが低下する。
　したがって、ＴｉとＡｌの複合窒化物または複合炭窒化物層中に存在する微粒六方晶結晶粒の面積割合は、５面積％以下であることが好ましく、また、該微粒六方晶結晶粒の平均粒径Ｒは０．０１～０．３μｍとすることが好ましい。
　なお、ＮａＣｌ型の面心立方構造を有する結晶粒の粒界に存在する六方晶構造の微粒結晶粒は、透過型電子顕微鏡を用いて電子線回折図形を解析することにより同定することができ、また、六方晶構造の微粒結晶粒の平均粒子径は、粒界を含んだ１μｍ×１μｍの測定範囲内に存在する粒子について、粒径を測定し、それらの平均値を算出することによって求めることができる。  Fine hexagonal crystal grains present in the composite nitride or composite carbonitride layer of Ti and Al:
In the Ti and Al composite nitride or composite carbonitride layer of the present invention, fine crystal grains having a hexagonal structure can be contained in grain boundaries of crystal grains having a NaCl type face centered cubic structure.
The presence of fine hexagonal crystals at the grain boundaries of the NaCl-type face-centered cubic structure with excellent hardness suppresses the grain boundary slip, and the composite nitride or composite carbonitride layer of Ti and Al Toughness is improved. However, if the area ratio of the hexagonal crystal grains exceeds 5 area%, the hardness is relatively lowered, and the average grain size R of the hexagonal crystal grains is less than 0.01 μm. When it exists, the effect which suppresses a grain boundary sliding is not enough, On the other hand, when it exceeds 0.3 micrometer, the distortion in a layer will become large and hardness will fall.
Therefore, the area ratio of the fine hexagonal crystal grains present in the composite nitride or composite carbonitride layer of Ti and Al is preferably 5% by area or less, and the average grain of the fine hexagonal crystal grains The diameter R is preferably 0.01 to 0.3 μm.
In addition, the fine crystal grains of the hexagonal crystal structure present in the grain boundary of the crystal grains having the NaCl type face centered cubic structure can be identified by analyzing the electron diffraction pattern using a transmission electron microscope, Further, the average particle diameter of the fine crystal grains having a hexagonal crystal structure is obtained by measuring the particle diameter and calculating the average value of the particles existing within the measurement range of 1 μm × 1 μm including the grain boundary. Can do.
下部層および上部層：
　本発明の複合窒化物または複合炭窒化物層は、それだけでも十分な効果を奏するが、Ｔｉの炭化物層、窒化物層、炭窒化物層、炭酸化物層および炭窒酸化物層のうちの１層または２層以上のＴｉ化合物層からなり、０．１～２０μｍの合計平均層厚を有する下部層を設けた場合、および/または、少なくとも酸化アルミニウム層を含む上部層であって、該上部層の合計平均層厚が１～２５μｍである上部層を設けた場合には、これらの層が奏する効果と相俟って、一層すぐれた特性を創出することができる。Ｔｉの炭化物層、窒化物層、炭窒化物層、炭酸化物層および炭窒酸化物層のうちの１層または２層以上のＴｉ化合物層からなる下部層を設ける場合、下部層の合計平均層厚が０．１μｍ未満では、下部層の効果が十分に奏されず、一方、２０μｍを超えると結晶粒が粗大化し易くなり、チッピングを発生しやすくなる。また、酸化アルミニウム層を含む上部層の合計平均層厚が１μｍ未満では、上部層の効果が十分に奏されず、一方、２５μｍを超えると結晶粒が粗大化し易くなり、チッピングを発生しやすくなる。 Lower layer and upper layer:
The composite nitride or composite carbonitride layer of the present invention alone has a sufficient effect, but one of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride oxide layer. A lower layer comprising a layer or two or more Ti compound layers and having a total average layer thickness of 0.1 to 20 μm, and / or an upper layer including at least an aluminum oxide layer, the upper layer In the case where an upper layer having a total average layer thickness of 1 to 25 μm is provided, it is possible to create better characteristics in combination with the effects of these layers. When providing a lower layer made of one or two or more Ti compound layers of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride oxide layer, the total average layer of the lower layer If the thickness is less than 0.1 μm, the effect of the lower layer is not sufficiently achieved. On the other hand, if it exceeds 20 μm, the crystal grains are likely to be coarsened and chipping is likely to occur. Further, if the total average layer thickness of the upper layer including the aluminum oxide layer is less than 1 μm, the effect of the upper layer is not sufficiently achieved. On the other hand, if it exceeds 25 μm, the crystal grains are likely to be coarsened and chipping is likely to occur. .
　本発明は、工具基体の表面に、硬質被覆層を設けた表面被覆切削工具において、硬質被覆層が、化学蒸着法により成膜されたＴｉとＡｌの複合窒化物または複合炭窒化物層を少なくとも含み、複合窒化物または複合炭窒化物層にはＮａＣｌ型の面心立方構造を有する結晶粒が存在し、また、ＮａＣｌ型の面心立方構造を有する結晶粒内には、ＴｉとＡｌの周期的な濃度変化が存在し、かつ、周期的な濃度変化の方向は、工具基体表面に平行な面となす角度が３０度以内の方向である結晶粒が少なくとも存在することから、切削加工時に加わる剪断力に対しての緩衝作用によって、工具基体と平行な方向へのクラックの進展が抑制され、耐チッピング性、耐欠損性が向上する。
　さらに、本発明の複合窒化物または複合炭窒化物層は、組成式：（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）で表した場合、ＡｌのＴｉとＡｌの合量に占める平均含有割合ＸａｖｇおよびＣのＣとＮの合量に占める平均含有割合Ｙａｖｇ（但し、Ｘａｖｇ、Ｙａｖｇはいずれも原子比）が、それぞれ、０．４０≦Ｘａｖｇ≦０．９５、０≦Ｙａｖｇ≦０．００５を満足することが好ましく、また、前記濃度変化の周期は１～１０ｎｍであり、かつ、周期的に変化するＡｌの含有割合ｘの極大値の平均と極小値の平均の差は０．０１～０．１であることが好ましく、さらに、複合窒化物または複合炭窒化物層のＮａＣｌ型の面心立方構造を有する結晶粒の粒界部に、六方晶構造を有する平均粒径Ｒが０．０１～０．３μｍの微粒結晶粒が面積割合で５面積％以下存在することが好ましい。
　そして、上記の硬質被覆層を備える本発明の被覆工具は、切れ刃に断続的・衝撃的負荷が作用する合金鋼、鋳鉄、ステンレス鋼等の高速断続切削加工に用いた場合においても、チッピング、欠損を発生することなく、長期の使用に亘ってすぐれた耐摩耗性を発揮するのである。 The present invention provides a surface-coated cutting tool in which a hard coating layer is provided on the surface of a tool base, wherein the hard coating layer includes at least a composite nitride or composite carbonitride layer of Ti and Al formed by chemical vapor deposition. In addition, crystal grains having a NaCl type face centered cubic structure are present in the composite nitride or composite carbonitride layer, and within the crystal grains having the NaCl type face centered cubic structure, a cycle of Ti and Al is present. Since there are at least crystal grains whose angle to the plane parallel to the surface of the tool base is within 30 degrees, there is a periodic concentration change and there is a periodic concentration change direction. The buffering action against the shearing force suppresses the development of cracks in the direction parallel to the tool base, thereby improving the chipping resistance and fracture resistance.
Furthermore, the composite nitride or composite carbonitride layer of the present invention occupies the total amount of Ti and Al in the Al when expressed by the composition formula: (Ti 1-x Al x ) (C y N 1-y ). The average content ratio X avg and the average content ratio Y avg in the total amount of C and N in C (where X avg and Y avg are atomic ratios) are respectively 0.40 ≦ X avg ≦ 0.95, It is preferable that 0 ≦ Y avg ≦ 0.005 is satisfied, the period of the concentration change is 1 to 10 nm, and the average and minimum values of the maximal value of the Al content ratio x that varies periodically The average difference is preferably 0.01 to 0.1. Furthermore, a hexagonal crystal structure is formed at the grain boundary portion of the crystal nitride having a NaCl-type face-centered cubic structure of the composite nitride or composite carbonitride layer. Fine crystal grains having an average grain size R of 0.01 to 0.3 μm It is preferably present in area ratio 5 area% or less.
And the coated tool of the present invention provided with the above hard coating layer, even when used for high-speed intermittent cutting of alloy steel, cast iron, stainless steel, etc. in which intermittent and impact loads act on the cutting edge, chipping, It exhibits excellent wear resistance over a long period of use without causing defects.
本発明の硬質被覆層を構成するＴｉとＡｌの複合窒化物または複合炭窒化物層の断面を模式的に表した膜構成模式図である。It is the film | membrane structure schematic diagram which represented typically the cross section of the composite nitride or composite carbonitride layer of Ti and Al which comprises the hard coating layer of this invention. 本発明の硬質被覆層を構成するＴｉとＡｌの複合窒化物または複合炭窒化物層のＮａＣｌ型の面心立方構造を有する結晶粒について、ＴｉとＡｌの周期的な濃度変化が存在することを示す模式図である。Regarding the crystal grains having the NaCl-type face-centered cubic structure of the composite nitride of Ti and Al or the composite carbonitride layer constituting the hard coating layer of the present invention, there is a periodic concentration change of Ti and Al. It is a schematic diagram shown. 本発明の硬質被覆層を構成するＴｉとＡｌの複合窒化物または複合炭窒化物層のＮａＣｌ型の面心立方構造を有する結晶粒について、工具基体表面に平行な面となす角度が３０度以内の方向に形成される該ＴｉとＡｌの周期的な濃度変化を示す概略模式図である。With respect to crystal grains having a face-centered cubic structure of the Ti-Al composite nitride or composite carbonitride layer constituting the hard coating layer of the present invention, the angle formed with a plane parallel to the tool substrate surface is within 30 degrees. It is a schematic diagram which shows the periodic density | concentration change of this Ti and Al formed in this direction. 本発明のＮａＣｌ型の面心立方構造を有する結晶粒内に存在するＴｉとＡｌの濃度変化の様子を、透過型電子顕微鏡を用いて、エネルギー分散型Ｘ線分光法（ＥＤＳ）による線分析を行って求めたＴｉとＡｌの周期的な濃度変化の一例を示すグラフである。The state of Ti and Al concentration changes in the crystal grains having the NaCl type face-centered cubic structure of the present invention is analyzed by energy dispersive X-ray spectroscopy (EDS) using a transmission electron microscope. It is a graph which shows an example of the periodic density | concentration change of Ti and Al calculated | required.
　つぎに、本発明の被覆工具を実施例により具体的に説明する。 Next, the coated tool of the present invention will be specifically described with reference to examples.
　原料粉末として、いずれも１～３μｍの平均粒径を有するＷＣ粉末、ＴｉＣ粉末、ＴａＣ粉末、ＮｂＣ粉末、Ｃｒ3Ｃ2粉末およびＣｏ粉末を用意し、これら原料粉末を、表１に示される配合組成に配合し、さらにワックスを加えてアセトン中で２４時間ボールミル混合し、減圧乾燥した後、９８ＭＰａの圧力で所定形状の圧粉体にプレス成形し、この圧粉体を５Ｐａの真空中、１３７０～１４７０℃の範囲内の所定の温度に１時間保持の条件で真空焼結し、焼結後、ＩＳＯ規格ＳＥＥＮ１２０３ＡＦＳＮのインサート形状をもったＷＣ基超硬合金製の工具基体Ａ～Ｃをそれぞれ製造した。 As raw material powders, WC powder, TiC powder, TaC powder, NbC powder, Cr 3 C 2 powder and Co powder all having an average particle diameter of 1 to 3 μm are prepared, and these raw material powders are blended as shown in Table 1. Blended into the composition, added with wax, mixed in a ball mill in acetone for 24 hours, dried under reduced pressure, pressed into a compact of a predetermined shape at a pressure of 98 MPa, and the compact was 1370 in a vacuum of 5 Pa. Vacuum sintered under the condition of holding for 1 hour at a predetermined temperature in the range of ~ 1470 ° C, and after sintering, manufacture tool bodies A to C made of WC-base cemented carbide with ISO standard SEEN1203AFSN insert shape, respectively. did.
　また、原料粉末として、いずれも０．５～２μｍの平均粒径を有するＴｉＣＮ（質量比でＴｉＣ／ＴｉＮ＝５０／５０）粉末、Ｍｏ2Ｃ粉末、ＺｒＣ粉末、ＮｂＣ粉末、ＷＣ粉末、Ｃｏ粉末およびＮｉ粉末を用意し、これら原料粉末を、表２に示される配合組成に配合し、ボールミルで２４時間湿式混合し、乾燥した後、９８ＭＰａの圧力で圧粉体にプレス成形し、この圧粉体を１．３ｋＰａの窒素雰囲気中、温度：１５００℃に１時間保持の条件で焼結し、焼結後、ＩＳＯ規格ＳＥＥＮ１２０３ＡＦＳＮのインサート形状をもったＴｉＣＮ基サーメット製の工具基体Ｄを作製した。 In addition, as raw material powders, TiCN (mass ratio TiC / TiN = 50/50) powder, Mo 2 C powder, ZrC powder, NbC powder, WC powder, Co powder, all having an average particle diameter of 0.5 to 2 μm. And Ni powder are prepared, these raw material powders are blended in the blending composition shown in Table 2, wet mixed by a ball mill for 24 hours, dried, and then pressed into a compact at a pressure of 98 MPa. The body was sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, a tool base D made of TiCN-based cermet having an ISO standard SEEN1203AFSN insert shape was produced.
　つぎに、これらの工具基体Ａ～Ｄの表面に、化学蒸着装置を用い、表４、表５に示される形成条件Ａ～Ｊ、即ち、第1段階成膜条件で成膜初期層を形成し、次いで、第２段階成膜条件で成膜することにより、表７に示される本発明被覆工具１～１０を製造した。
　つまり、表４、表５に示される形成条件Ａ～Ｊにしたがい、ＮＨ３とＨ２からなるガス群Ａと、ＴｉＣｌ４、ＡｌＣｌ３、Ｎ２、Ｈ２からなるガス群Ｂ、および、おのおのガスの供給方法として、反応ガス組成（ガス群Ａおよびガス群Ｂを合わせた全体に対する容量％）を、ガス群ＡとしてＮＨ３：１．０～２．５％、Ｈ２：６０～７５％、ガス群ＢとしてＡｌＣｌ３：０．１０～０．９０％、ＴｉＣｌ４：０．１０～０．３０％、Ｎ２：０．０～１２．０％、Ｃ２Ｈ４：０～０．５％、Ｈ２：残、反応雰囲気圧力：４．５～５．０ｋＰａ、反応雰囲気温度：７００～８００℃、供給周期１～２秒、１周期当たりのガス供給時間０．０５～０．１２秒、ガス群Ａの供給とガス群Ｂの供給の位相差０．０４～０．０９秒として、所定時間、熱ＣＶＤ法を行い、表７に示される（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）層を成膜することにより本発明被覆工具１～１０を製造した。
　また、本発明においては、前記複合窒化物または複合炭窒化物層の成膜温度は低温である方が、成膜初期層中のポアの割合が少なくなり、硬さが高くなる、あるいは前記複合窒化物または複合炭窒化物層と下部層の密着強度が高くなり、耐剥離性が向上する効果がある。一方、前記複合窒化物または複合炭窒化物層の成膜の成膜温度が高温である方が、結晶性が高くなり、耐摩耗性が向上する効果があるため、本発明では、成膜を２段階に分けて行い、かつ、第１段階成膜を第２段階成膜よりも低温にすることによって、耐剥離性、耐摩耗性を向上させている。
　なお、本発明被覆工具１～１０については、それぞれ、表３に示される形成条件で、表６に示される下部層、上部層を形成した。 Next, a chemical vapor deposition apparatus is used on the surfaces of these tool bases A to D to form an initial film formation layer under the formation conditions A to J shown in Tables 4 and 5, that is, the first stage film formation conditions. Then, the coated tools 1 to 10 of the present invention shown in Table 7 were manufactured by forming a film under the second-stage film forming conditions.
That is, according to the formation conditions A to J shown in Tables 4 and 5, a gas group A composed of NH 3 and H 2 , a gas group B composed of TiCl 4 , AlCl 3 , N 2 , and H 2 , and each As a gas supply method, the reaction gas composition (capacity% with respect to the total of the gas group A and the gas group B) is set to NH 3 : 1.0 to 2.5% and H 2 : 60 to 75% as the gas group A. As gas group B, AlCl 3 : 0.10 to 0.90%, TiCl 4 : 0.10 to 0.30%, N 2 : 0.0 to 12.0%, C 2 H 4 : 0 to 0. 5%, H 2 : remaining, reaction atmosphere pressure: 4.5 to 5.0 kPa, reaction atmosphere temperature: 700 to 800 ° C., supply cycle 1 to 2 seconds, gas supply time 0.05 to 0.12 per cycle Second, the phase difference between the gas group A supply and the gas group B supply is 0.04 to 0.09 seconds. The coated tools 1 to 10 of the present invention were manufactured by performing a thermal CVD method for a predetermined time to form a (Ti 1-x Al x ) (C y N 1-y ) layer shown in Table 7.
In the present invention, the lower the film formation temperature of the composite nitride or composite carbonitride layer, the lower the proportion of pores in the initial film formation layer, the higher the hardness, or the composite Adhesive strength between the nitride or composite carbonitride layer and the lower layer is increased, and the peel resistance is improved. On the other hand, the higher the film formation temperature of the composite nitride or composite carbonitride layer, the higher the crystallinity and the effect of improving the wear resistance. Peeling resistance and wear resistance are improved by performing the process in two stages and making the first stage film formation at a lower temperature than the second stage film formation.
For the inventive coated tools 1 to 10, the lower layer and the upper layer shown in Table 6 were formed under the formation conditions shown in Table 3, respectively.
　また、比較の目的で、工具基体Ａ～Ｄの表面に、表４および表５に示される比較成膜工程の条件で、表８に示される目標層厚（μｍ）で本発明被覆工具１～１０と同様に、少なくともＴｉとＡｌの複合窒化物または複合炭窒化物層を含む硬質被覆層を蒸着形成し比較被覆工具１～１０を製造した。この時には、（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）層の成膜工程中に、工具基体表面における反応ガス組成が時間的に変化しない様に硬質被覆層を形成することにより比較被覆工具１～１０を製造した。
　なお、本発明被覆工具１～１０と同様に、比較被覆工具１～１０については、表３に示される形成条件で、表６に示される下部層、上部層を形成した。 For comparison purposes, the coated tools 1 to 4 of the present invention are formed on the surfaces of the tool bases A to D with the target layer thickness (μm) shown in Table 8 under the conditions of the comparative film forming process shown in Tables 4 and 5. In the same manner as in No. 10, comparative coating tools 1 to 10 were produced by vapor-depositing a hard coating layer including at least a composite nitride or composite carbonitride layer of Ti and Al. At this time, by forming a hard coating layer so that the reaction gas composition on the surface of the tool base does not change with time during the film forming process of the (Ti 1-x Al x ) (C y N 1-y ) layer. Comparative coated tools 1-10 were produced.
Similar to the coated tools 1 to 10 of the present invention, the comparative coated tools 1 to 10 were formed with the lower layer and the upper layer shown in Table 6 under the formation conditions shown in Table 3.
　本発明被覆工具１～１０、比較被覆工具１～１０の各構成層の工具基体に垂直な方向の断面を、走査型電子顕微鏡（倍率５０００倍）を用いて測定し、観察視野内の５点の層厚を測って平均して平均層厚を求めたところ、いずれも表７および表８に示される目標層厚と実質的に同じ平均層厚を示した。
　また、複合窒化物または複合炭窒化物層の平均Ａｌ含有割合Ｘａｖｇについては、電子線マイクロアナライザ（ＥＰＭＡ，Ｅｌｅｃｔｒｏｎ－Ｐｒｏｂｅ－Ｍｉｃｒｏ－Ａｎａｌｙｓｅｒ）を用い、表面を研磨した試料において、電子線を試料表面側から照射し、得られた特性Ｘ線の解析結果の１０点平均からＡｌの平均Ａｌ含有割合Ｘａｖｇを求めた。平均Ｃ含有割合Ｙａｖｇについては、二次イオン質量分析（ＳＩＭＳ，Ｓｅｃｏｎｄａｒｙ－Ｉｏｎ－Ｍａｓｓ－Ｓｐｅｃｔｒｏｓｃｏｐｙ）により求めた。イオンビームを試料表面側から７０μｍ×７０μｍの範囲に照射し、スパッタリング作用によって放出された成分について深さ方向の濃度測定を行った。平均Ｃ含有割合ＹａｖｇはＴｉとＡｌの複合窒化物または複合炭窒化物層についての深さ方向の平均値を示す。ただしＣの含有割合には、意図的にガス原料としてＣを含むガスを用いなくても含まれる不可避的なＣの含有割合を除外している。具体的にはＣ２Ｈ４の供給量を０とした場合の複合窒化物または複合炭窒化物層に含まれるＣ成分の含有割合（原子比）を不可避的なＣの含有割合として求め、Ｃ２Ｈ４を意図的に供給した場合に得られる複合窒化物または複合炭窒化物層に含まれるＣ成分の含有割合（原子比）から前記不可避的なＣの含有割合を差し引いた値をＹａｖｇとして求めた。 The cross-sections of the constituent layers of the inventive coated tools 1 to 10 and comparative coated tools 1 to 10 in the direction perpendicular to the tool substrate were measured using a scanning electron microscope (5000 magnifications), and 5 points within the observation field of view were measured. The average layer thickness was measured and averaged to obtain the average layer thickness. As a result, the average layer thickness was substantially the same as the target layer thickness shown in Tables 7 and 8.
The average Al content ratio X avg of the composite nitride or composite carbonitride layer was measured using an electron beam microanalyzer (EPMA, Electron-Probe-Micro-Analyzer). Irradiation was performed from the surface side, and an average Al content ratio X avg of Al was obtained from an average of 10 points of the analysis result of the obtained characteristic X-rays. The average C content ratio Y avg was determined by secondary ion mass spectrometry (SIMS, Secondary-Ion-Mass-Spectroscopy). The ion beam was irradiated in the range of 70 μm × 70 μm from the sample surface side, and the concentration in the depth direction was measured for the components emitted by the sputtering action. The average C content ratio Y avg indicates the average value in the depth direction of the composite nitride or composite carbonitride layer of Ti and Al. However, the content ratio of C excludes the inevitable content ratio of C that is included without intentionally using a gas containing C as a gas raw material. Specifically, the content ratio (atomic ratio) of the C component contained in the composite nitride or composite carbonitride layer when the supply amount of C 2 H 4 is 0 is determined as an inevitable C content ratio, and C Y avg is a value obtained by subtracting the unavoidable C content from the C component content (atomic ratio) contained in the composite nitride or composite carbonitride layer obtained when 2 H 4 is intentionally supplied. As sought.
　また、透過型電子顕微鏡を用いて、加速電圧２００ｋＶの条件において複合窒化物または複合炭窒化物層の微小領域の観察を行い、エネルギー分散型Ｘ線分光法（ＥＤＳ）を用いて、断面側から面分析を行うことによって、前記立方晶構造を有する結晶粒内に、組成式：（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）におけるＴｉとＡｌの周期的な濃度変化が存在するか否かを確認し、本発明濃度変化の方向を有する結晶粒の面積割合を求めた。
　表７、表８にその結果を示す。さらに、上記周期的な濃度変化の方向について、工具基体表面に平行な面となす角度を次のようにして測定した。
　透過型電子顕微鏡を用いて、前記ＮａＣｌ型の面心立方構造を有する結晶粒内における基体と垂直な任意の断面から任意の１μｍ×１μｍの領域において観察を行い、ＴｉとＡｌの周期的な濃度変化が存在し、前記断面におけるＴｉとＡｌの周期的な濃度変化の周期が最小になる方向と工具基体表面のなす角を測定することにより、求めることが出来る。そして、測定された「周期的な濃度変化の周期が最小になる方向と工具基体表面のなす角」のうちで、最小の角度を、周期的濃度変化の方向（度）として、この周期的な濃度変化の方向が３０度以内であるかを判定した。この周期的な濃度変化の方向が３０度以内である場合を「有」、３０度を超える場合を「無」として表７、表８に示す。 In addition, a transmission electron microscope was used to observe a minute region of the composite nitride or composite carbonitride layer under the condition of an acceleration voltage of 200 kV, and from the cross-sectional side using energy dispersive X-ray spectroscopy (EDS). By performing surface analysis, periodic concentration changes of Ti and Al in the composition formula: (Ti 1-x Al x ) (C y N 1-y ) exist in the crystal grains having the cubic structure. Whether or not, and the area ratio of the crystal grains having the direction of concentration change of the present invention was determined.
Tables 7 and 8 show the results. Furthermore, with respect to the direction of the periodic density change, the angle formed with the plane parallel to the tool base surface was measured as follows.
Using a transmission electron microscope, observation is performed in an arbitrary area of 1 μm × 1 μm from an arbitrary cross section perpendicular to the substrate in the crystal grains having the NaCl-type face-centered cubic structure, and a periodic concentration of Ti and Al There is a change, and it can be obtained by measuring the angle between the direction of the periodic concentration change of Ti and Al in the cross section and the tool substrate surface. Of the measured “angle between the direction in which the periodic concentration change period is minimized and the angle formed by the tool base surface”, the minimum angle is defined as the periodic concentration change direction (degrees). It was determined whether the direction of density change was within 30 degrees. Tables 7 and 8 show the case where the direction of the periodic density change is within 30 degrees as “Yes” and the case where it exceeds 30 degrees as “No”.
　また、該周期的な濃度変化が存在する前記立方晶構造を有する結晶粒について、透過型電子顕微鏡を用いた微小領域の観察と、エネルギー分散型Ｘ線分光法（ＥＤＳ）を用いた断面側からの面分析により、ＴｉとＡｌの濃度変化の周期を求めた。
　周期の測定方法としては、該結晶粒について、前記面分析の結果に基づいて組成の濃淡から１０周期分程度の濃度変化が測定範囲に入る様に倍率を設定した上で、工具基体表面の周期的な濃度変化の方向に沿ってＥＤＳによる線分析による周期測定を少なくとも５周期分の範囲で行い、その平均値をＴｉとＡｌの周期的な濃度変化の周期として求めた。
　さらに、周期的な濃度変化におけるＡｌの含有割合ｘの極大値の平均および極小値の平均の差Δｘを求めた。
　具体的な測定手法は以下のとおりである。
　該結晶粒について、前記面分析の結果に基づいて組成の濃淡から１０周期分程度の濃度変化が測定範囲に入る様に倍率を設定した上で、工具基体表面の周期的な濃度変化の方向に沿ってＥＤＳによる線分析を少なくとも５周期分の範囲で行い、ＴｉとＡｌの周期的な濃度変化の極大値と極小値のそれぞれの平均値の差をΔｘとして求めた。
　前記「周期的な濃度変化の周期が最小になる方向と工具基体表面のなす角」のうちで、最小の測定値が得られた結晶粒について、その周期とΔｘを表７、表８に示す。 In addition, for the crystal grains having the cubic structure in which the periodic concentration change exists, observation of a minute region using a transmission electron microscope and from a cross-sectional side using energy dispersive X-ray spectroscopy (EDS) From the surface analysis, the period of Ti and Al concentration change was determined.
As a method of measuring the cycle, the crystal grains are set to a magnification so that a change in concentration of about 10 cycles from the density of the composition enters the measurement range based on the result of the surface analysis, and then the cycle of the tool base surface is set. Periodic measurement by line analysis by EDS was performed in the range of at least 5 periods along the direction of typical concentration change, and the average value was obtained as the period of periodic concentration change of Ti and Al.
Furthermore, the difference Δx between the average of the maximum value and the average of the minimum value of the Al content ratio x in the periodic concentration change was obtained.
The specific measurement method is as follows.
For the crystal grains, the magnification is set so that the concentration change of about 10 cycles from the density of the composition enters the measurement range based on the result of the surface analysis, and then in the direction of the periodic concentration change on the tool base surface. Accordingly, line analysis by EDS was performed in a range of at least 5 cycles, and the difference between the average values of the maximum and minimum values of the periodic concentration change of Ti and Al was determined as Δx.
Table 7 and Table 8 show the period and Δx of the crystal grains for which the minimum measured value is obtained out of the “angle between the direction in which the period of periodic concentration change is minimized and the surface of the tool base”. .
　また、前記複合窒化物または複合炭窒化物層について、透過型電子顕微鏡を用いて複数視野に亘って観察し、ＮａＣｌ型の面心立方構造を有する結晶粒の粒界部に六方晶構造の微粒結晶粒が存在する面積割合および六方晶構造の微粒結晶粒の平均粒径Ｒを測定した。
　なお、粒界に存在する微粒六方晶の同定は透過型電子顕微鏡を用いて電子線回折図形を解析することにより同定した。微粒六方晶の平均粒子径は粒界を含んだ１μｍ×１μｍの測定範囲内に存在する粒子について、粒径を測定し、微粒六方晶の総面積を算出した値から面積割合を求めた。また、粒径は六方晶と同定した粒に対して外接円を作成し、その外接円の半径を求め、その平均値を粒径とした。
　表７、表８に、得られた結果を示す。 Further, the composite nitride or the composite carbonitride layer is observed over a plurality of fields of view using a transmission electron microscope, and a hexagonal structure fine grain is formed at a grain boundary portion of a crystal grain having an NaCl type face centered cubic structure. The area ratio of the crystal grains and the average grain size R of the hexagonal crystal grains were measured.
Incidentally, the identification of the fine hexagonal crystal existing at the grain boundary was carried out by analyzing the electron diffraction pattern using a transmission electron microscope. The average particle size of the fine hexagonal crystals was determined by measuring the particle size of particles present in the measurement range of 1 μm × 1 μm including the grain boundaries and calculating the total area of the fine hexagonal crystals. For the grain size, a circumscribed circle was created for the grains identified as hexagonal crystals, the radius of the circumscribed circle was determined, and the average value was taken as the grain size.
Tables 7 and 8 show the obtained results.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
　つぎに、前記各種の被覆工具をいずれもカッタ径１２５ｍｍの工具鋼製カッタ先端部に固定治具にてクランプした状態で、本発明被覆工具１～１０、比較被覆工具１～１０について、以下に示す、合金鋼の高速断続切削の一種である湿式高速正面フライス、センターカット切削加工試験を実施し、切刃の逃げ面摩耗幅を測定した。
その結果を表９に示す。 Next, the coated tools 1 to 10 of the present invention and the comparative coated tools 1 to 10 are clamped at the tip of a tool steel cutter having a cutter diameter of 125 mm with a fixing jig. A wet high-speed face milling, which is a kind of high-speed interrupted cutting of alloy steel, and a center-cut cutting test were performed, and the flank wear width of the cutting edge was measured.
The results are shown in Table 9.
　工具基体：炭化タングステン基超硬合金、炭窒化チタン基サーメット、
　切削試験：　湿式高速正面フライス、センターカット切削加工、
　カッタ径：　１２５　ｍｍ、
　被削材：　　ＪＩＳ・ＳＣＭ４４０幅１００ｍｍ、長さ４００ｍｍのブロック材、
　回転速度：　９９４　ｍｉｎ－１、
　切削速度：　３９０　ｍ／ｍｉｎ、
　切り込み：　３．０　ｍｍ、
　一刃送り量：　０．２　ｍｍ／刃、
　切削時間：　６分、
（通常の切削速度は、２２０ｍ／ｍｉｎ）、 Tool substrate: Tungsten carbide-based cemented carbide, titanium carbonitride-based cermet,
Cutting test: wet high speed face milling, center cut cutting,
Cutter diameter: 125 mm,
Work material: JIS / SCM440 block material with a width of 100 mm and a length of 400 mm,
Rotational speed: 994 min-1,
Cutting speed: 390 m / min,
Cutting depth: 3.0 mm,
Single blade feed rate: 0.2 mm / tooth,
Cutting time: 6 minutes,
(Normal cutting speed is 220 m / min),
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
　原料粉末として、いずれも１～３μｍの平均粒径を有するＷＣ粉末、ＴｉＣ粉末、ＺｒＣ粉末、ＴａＣ粉末、ＮｂＣ粉末、Ｃｒ3Ｃ2粉末、ＴｉＮ粉末およびＣｏ粉末を用意し、これら原料粉末を、表１０に示される配合組成に配合し、さらにワックスを加えてアセトン中で２４時間ボールミル混合し、減圧乾燥した後、９８ＭＰａの圧力で所定形状の圧粉体にプレス成形し、この圧粉体を５Ｐａの真空中、１３７０～１４７０℃の範囲内の所定の温度に１時間保持の条件で真空焼結し、焼結後、切刃部にＲ：０．０７ｍｍのホーニング加工を施すことによりＩＳＯ規格ＣＮＭＧ１２０４１２のインサート形状をもったＷＣ基超硬合金製の工具基体Ｅ～Ｇをそれぞれ製造した。 As raw material powders, WC powder, TiC powder, ZrC powder, TaC powder, NbC powder, Cr 3 C 2 powder, TiN powder and Co powder each having an average particle diameter of 1 to 3 μm are prepared. Compounded in the formulation shown in Table 10, added with wax, ball mill mixed in acetone for 24 hours, dried under reduced pressure, press-molded into a green compact of a predetermined shape at a pressure of 98 MPa. In a 5 Pa vacuum, vacuum sintering is performed at a predetermined temperature within a range of 1370 to 1470 ° C. for 1 hour, and after sintering, the cutting edge is subjected to a honing process of R: 0.07 mm. Tool bases E to G made of WC-base cemented carbide having an insert shape of CNMG120212 were produced.
　また、原料粉末として、いずれも０．５～２μｍの平均粒径を有するＴｉＣＮ（質量比でＴｉＣ／ＴｉＮ＝５０／５０）粉末、ＮｂＣ粉末、ＷＣ粉末、Ｃｏ粉末、およびＮｉ粉末を用意し、これら原料粉末を、表１１に示される配合組成に配合し、ボールミルで２４時間湿式混合し、乾燥した後、９８ＭＰａの圧力で圧粉体にプレス成形し、この圧粉体を１．３ｋＰａの窒素雰囲気中、温度：１５００℃に１時間保持の条件で焼結し、焼結後、切刃部分にＲ：０．０９ｍｍのホーニング加工を施すことによりＩＳＯ規格・ＣＮＭＧ１２０４１２のインサート形状をもったＴｉＣＮ基サーメット製の工具基体Ｈを形成した。 In addition, as raw material powders, TiCN (TiC / TiN = 50/50 by mass ratio) powder, NbC powder, WC powder, Co powder, and Ni powder each having an average particle diameter of 0.5 to 2 μm are prepared, These raw material powders were blended into the composition shown in Table 11, wet mixed with a ball mill for 24 hours, dried, and then pressed into a green compact at a pressure of 98 MPa. Sintered in an atmosphere at a temperature of 1500 ° C. for 1 hour, and after sintering, the cutting edge part is subjected to a honing process of R: 0.09 mm so that the TiCN base has an insert shape of ISO standard / CNMG120212 A tool substrate H made of cermet was formed.
　つぎに、これらの工具基体Ｅ～Ｇおよび工具基体Ｈの表面に、通常の化学蒸着装置を用い、表４、表５に示される形成条件Ａ～Ｊにより、所定時間、熱ＣＶＤ法を行い、表１３に示される（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）層を成膜することによりことにより本発明被覆工具１１～２０を製造した。
　なお、本発明被覆工具１１～２０については、表３に示される形成条件で、表１２に示される下部層、上部層を形成した。 Next, on the surfaces of the tool bases E to G and the tool base H, a thermal chemical vapor deposition method is performed for a predetermined time according to the formation conditions A to J shown in Tables 4 and 5 using a normal chemical vapor deposition apparatus. By coating the (Ti 1-x Al x ) (C y N 1-y ) layer shown in Table 13, the coated tools 11 to 20 of the present invention were manufactured.
For the inventive coated tools 11 to 20, the lower layer and the upper layer shown in Table 12 were formed under the formation conditions shown in Table 3.
　また、比較の目的で、同じく工具基体Ｅ～Ｇおよび工具基体Ｈの表面に、通常の化学蒸着装置を用い、表４、表５に示される条件かつ目標層厚で本発明被覆工具と同様に硬質被覆層を蒸着形成することにより、表１４に示される比較被覆工具１１～２０を製造した。
　なお、本発明被覆工具１１～２０と同様に、比較被覆工具１１～２０については、表３に示される形成条件で、表１２に示される下部層、上部層を形成した。 Further, for the purpose of comparison, a normal chemical vapor deposition apparatus is used on the surfaces of the tool bases E to G and the tool base H, and the conditions and target layer thicknesses shown in Tables 4 and 5 are used in the same manner as the coated tool of the present invention. Comparative coating tools 11 to 20 shown in Table 14 were manufactured by vapor-depositing a hard coating layer.
Similar to the coated tools 11 to 20 of the present invention, the comparative coated tools 11 to 20 were formed with the lower layer and the upper layer shown in Table 12 under the formation conditions shown in Table 3.
　また、本発明被覆工具１１～２０、比較被覆工具１１～２０の各構成層の断面を、走査電子顕微鏡（倍率５０００倍）を用いて測定し、観察視野内の５点の層厚を測って平均して平均層厚を求めたところ、いずれも表１３および表１４に示される目標層厚と実質的に同じ平均層厚を示した。
　また、前記本発明被覆工具１１～２０、比較被覆工具１１～２０の硬質被覆層について、実施例１に示される方法と同様の方法を用いて、平均Ａｌ含有割合Ｘａｖｇ、平均Ｃ含有割合Ｙａｖｇを測定した。
　その結果を、表１３および表１４に示す。 In addition, the cross-sections of the constituent layers of the inventive coated tools 11 to 20 and comparative coated tools 11 to 20 were measured using a scanning electron microscope (5000 times magnification), and the layer thicknesses at five points in the observation field were measured. When the average layer thickness was obtained by averaging, all showed the same average layer thickness as the target layer thickness shown in Table 13 and Table 14.
For the hard coating layers of the inventive coated tools 11-20 and comparative coated tools 11-20 , the average Al content ratio X avg , the average C content ratio Y was determined using the same method as shown in Example 1. avg was measured.
The results are shown in Table 13 and Table 14.
　前記本発明被覆工具１１～２０の硬質被覆層を構成するＴｉとＡｌの複合窒化物または複合炭窒化物の立方晶結晶粒内に、ＴｉとＡｌの周期的な組成分布が存在していることを透過型電子顕微鏡（倍率２０００００倍）を用いて、エネルギー分散型Ｘ線分光法（ＥＤＳ）による面分析により確認し、さらに、ｘの極大値の平均と極小値の平均の差Δｘを求めた。
　さらに、周期的な濃度変化が存在する前記立方晶構造を有する結晶粒について、同じく透過型電子顕微鏡を用いた微小領域の観察と、エネルギー分散型Ｘ線分光法（ＥＤＳ）を用いた断面側からの面分析により、ＴｉとＡｌの濃度変化の周期を求めた。 A periodic composition distribution of Ti and Al exists in the cubic crystal grains of the composite nitride of Ti and Al or the composite carbonitride constituting the hard coating layer of the inventive coated tools 11 to 20. Was confirmed by surface analysis using energy dispersive X-ray spectroscopy (EDS) using a transmission electron microscope (magnification: 200,000 times), and the difference Δx between the average of the maximum value of x and the average of the minimum value was obtained. .
Furthermore, for the crystal grains having the cubic structure in which the periodic concentration change exists, the microscopic region is observed using the transmission electron microscope and the cross section side using the energy dispersive X-ray spectroscopy (EDS) is used. From the surface analysis, the period of Ti and Al concentration change was determined.
　また、前記複合窒化物または複合炭窒化物層について、透過型電子顕微鏡と電子線後方散乱回折装置を用いて、ＮａＣｌ型の面心立方構造を有する結晶粒の粒界部に存在する六方晶の微粒結晶粒の結晶構造、平均粒径Ｒおよび面積割合を測定した。
　これらの結果を、表１３および表１４に示す。 Further, for the composite nitride or composite carbonitride layer, using a transmission electron microscope and an electron beam backscatter diffractometer, hexagonal crystals existing in the grain boundary part of the crystal grains having the NaCl type face centered cubic structure are used. The crystal structure, average particle diameter R and area ratio of the fine crystal grains were measured.
These results are shown in Table 13 and Table 14.
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000014
Figure JPOXMLDOC01-appb-T000014
　つぎに、前記各種の被覆工具をいずれも工具鋼製バイトの先端部に固定治具にてネジ止めした状態で、本発明被覆工具１１～２０、比較被覆工具１１～２０について、以下に示す、ステンレス鋼の湿式高速断続切削試験、鋳鉄の湿式高速断続切削試験を実施し、いずれも切刃の逃げ面摩耗幅を測定した。
　切削条件１：
　被削材：ＪＩＳ・ＳＵＳ３０４の長さ方向等間隔４本縦溝入り丸棒、
　切削速度：３００　ｍ／ｍｉｎ、
　切り込み：１．５　ｍｍ、
　送り：０．２　ｍｍ／ｒｅｖ、
　切削時間：２　分、
（通常の切削速度は、１５０ｍ／ｍｉｎ）、
　切削条件２：
　被削材：ＪＩＳ・ＦＣＤ８００の長さ方向等間隔４本縦溝入り丸棒、
　切削速度：３５０　ｍ／ｍｉｎ、
　切り込み：２．０　ｍｍ、
　送り：０．３　ｍｍ／ｒｅｖ、
　切削時間：３　分、
（通常の切削速度は、２００ｍ／ｍｉｎ）、
　表１５に、前記切削試験の結果を示す。 Next, the present coated tools 11 to 20 and the comparative coated tools 11 to 20 are shown below with all of the various coated tools screwed to the tip of the tool steel tool with a fixing jig. A wet high-speed intermittent cutting test for stainless steel and a wet high-speed intermittent cutting test for cast iron were performed, and the flank wear width of the cutting edge was measured for both.
Cutting condition 1:
Work material: JIS / SUS304 lengthwise equidistant four round grooved round bars,
Cutting speed: 300 m / min,
Cutting depth: 1.5 mm,
Feed: 0.2 mm / rev,
Cutting time: 2 minutes,
(Normal cutting speed is 150 m / min),
Cutting condition 2:
Work material: JIS / FCD800 lengthwise equidistant 4 round bars with vertical grooves,
Cutting speed: 350 m / min,
Cutting depth: 2.0 mm,
Feed: 0.3 mm / rev,
Cutting time: 3 minutes,
(Normal cutting speed is 200 m / min),
Table 15 shows the results of the cutting test.
Figure JPOXMLDOC01-appb-T000015
Figure JPOXMLDOC01-appb-T000015
　原料粉末として、いずれも０．５～４μｍの範囲内の平均粒径を有するｃＢＮ粉末、ＴｉＮ粉末、ＴｉＣ粉末、Ａｌ粉末、Ａｌ２Ｏ３粉末を用意し、これら原料粉末を表１６に示される配合組成に配合し、ボールミルで８０時間湿式混合し、乾燥した後、１２０ＭＰａの圧力で直径：５０ｍｍ×厚さ：１．５ｍｍの寸法をもった圧粉体にプレス成形し、ついでこの圧粉体を、圧力：１Ｐａの真空雰囲気中、９００～１３００℃の範囲内の所定温度に６０分間保持の条件で焼結して切刃片用予備焼結体とし、この予備焼結体を、別途用意した、Ｃｏ：８質量％、ＷＣ：残りの組成、並びに直径：５０ｍｍ×厚さ：２ｍｍの寸法をもったＷＣ基超硬合金製支持片と重ね合わせた状態で、通常の超高圧焼結装置に装入し、通常の条件である圧力：４ＧＰａ、温度：１２００～１４００℃の範囲内の所定温度に保持時間：０．８時間の条件で超高圧焼結し、焼結後上下面をダイヤモンド砥石を用いて研磨し、ワイヤー放電加工装置にて所定の寸法に分割し、さらにＣｏ：５質量％、ＴａＣ：５質量％、ＷＣ：残りの組成およびＪＩＳ規格ＣＮＧＡ１２０４０８の形状（厚さ：４．７６mm×内接円直径：１２．７mmの８０°菱形）をもったＷＣ基超硬合金製インサート本体のろう付け部（コーナー部）に、質量％で、Ｚｒ：３７．５％、Ｃｕ：２５％、Ｔｉ：残りからなる組成を有するＴｉ－Ｚｒ－Ｃｕ合金のろう材を用いてろう付けし、所定寸法に外周加工した後、切刃部に幅：０．１３ｍｍ、角度：２５°のホーニング加工を施し、さらに仕上げ研摩を施すことによりＩＳＯ規格ＣＮＧＡ１２０４０８のインサート形状をもった工具基体イ、ロをそれぞれ製造した。 As the raw material powder, cBN powder, TiN powder, TiC powder, Al powder, and Al 2 O 3 powder each having an average particle diameter in the range of 0.5 to 4 μm were prepared. These raw material powders are shown in Table 16. After blending into the blended composition, wet mixing with a ball mill for 80 hours, drying, and press-molding into a green compact with a diameter of 50 mm × thickness: 1.5 mm at a pressure of 120 MPa, and then this green compact Is sintered in a vacuum atmosphere at a pressure of 1 Pa at a predetermined temperature in the range of 900 to 1300 ° C. for 60 minutes to obtain a presintered body for a cutting edge piece, and this presintered body is separately prepared. A normal ultra high pressure sintering apparatus in a state of being superposed on a support piece made of WC base cemented carbide having Co: 8 mass%, WC: remaining composition, and diameter: 50 mm × thickness: 2 mm Normal pressure: 4 Pa, temperature: Presence at a predetermined temperature in the range of 1200 to 1400 ° C. Holding time: 0.8 hours under high pressure sintering, and after sintering, the upper and lower surfaces are polished with a diamond grindstone, and used in a wire electric discharge machine. And further divided into predetermined dimensions, Co: 5 mass%, TaC: 5 mass%, WC: remaining composition and shape of JIS standard CNGA120408 (thickness: 4.76 mm × inscribed circle diameter: 12.7 mm, 80 The brazing part (corner part) of the insert body made of a WC-base cemented carbide having a diamond) is Ti- having a composition consisting of Zr: 37.5%, Cu: 25%, Ti: the remainder in mass%. After brazing using a brazing material of Zr-Cu alloy and processing the outer periphery to a predetermined size, the cutting edge is subjected to honing processing with a width of 0.13 mm and an angle of 25 °, and further subjected to final polishing to achieve ISO. Standard CNGA12 Tool substrate b having a 408 insert shape, The filtrate was produced, respectively.
Figure JPOXMLDOC01-appb-T000016
Figure JPOXMLDOC01-appb-T000016
　つぎに、これらの工具基体イ、ロの表面に、通常の化学蒸着装置を用い、実施例１と同様の方法により表４、表５に示される条件で、少なくとも（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）層を含む硬質被覆層を目標層厚で蒸着形成することにより、表１８に示される本発明被覆工具２１～２６を製造した。
　なお、本発明被覆工具２１～３０については、表３に示される形成条件で、表１７に示すような下部層、上部層を形成した。 Next, at least (Ti 1-x Al x ) under the conditions shown in Tables 4 and 5 by the same method as in Example 1 using a normal chemical vapor deposition apparatus on the surfaces of these tool substrates A and B. The coated tools 21 to 26 of the present invention shown in Table 18 were manufactured by vapor-depositing a hard coating layer including a (C y N 1-y ) layer with a target layer thickness.
For the coated tools 21 to 30 of the present invention, the lower layer and the upper layer as shown in Table 17 were formed under the formation conditions shown in Table 3.
　また、比較の目的で、同じく工具基体イ、ロの表面に、通常の化学蒸着装置を用い、表４、表５に示される条件で、少なくとも（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）層を含む硬質被覆層を目標層厚で蒸着形成することにより、表１９に示される比較被覆工具２１～２６を製造した。
　なお、本発明被覆工具２１～３０と同様に、比較被覆工具２１～３０については、表３に示される形成条件で、表１７に示すような下部層、上部層を形成した。 Further, for the purpose of comparison, a normal chemical vapor deposition apparatus was used on the surfaces of the tool bases a and b, and at least (Ti 1-x Al x ) (C y N 1 ) under the conditions shown in Tables 4 and 5. Comparative coating tools 21 to 26 shown in Table 19 were manufactured by vapor-depositing a hard coating layer including a -y ) layer at a target layer thickness.
As with the inventive coated tools 21 to 30, the comparative coated tools 21 to 30 were formed with the lower layer and the upper layer as shown in Table 17 under the formation conditions shown in Table 3.
　また、本発明被覆工具２１～３０、比較被覆工具２１～３０の各構成層の断面を、走査電子顕微鏡（倍率５０００倍）を用いて測定し、観察視野内の５点の層厚を測って平均して平均層厚を求めたところ、いずれも表１８および表１９に示される目標層厚と実質的に同じ平均層厚を示した。 In addition, the cross-sections of the constituent layers of the inventive coated tool 21 to 30 and comparative coated tool 21 to 30 are measured using a scanning electron microscope (5000 times magnification), and the layer thickness at five points in the observation field is measured. When the average layer thickness was obtained by averaging, all showed the same average layer thickness as the target layer thickness shown in Table 18 and Table 19.
　また、前記本発明被覆工具２１～３０、比較被覆工具２１～３０の硬質被覆層について、実施例１に示される方法と同様の方法を用いて、平均Ａｌ含有割合Ｘａｖｇ、平均Ｃ含有割合Ｙａｖｇを測定した。
さらに、実施例１に示される方法と同様な方法を用いて、立方晶結晶粒内に存在するＴｉとＡｌの周期的な濃度変化の周期、濃度変化におけるｘの極大値の平均と極小値の平均の差Δｘ、また、ＮａＣｌ型の面心立方構造を有する個々の結晶粒の粒界部に存在する六方晶の微粒結晶粒の結晶構造、平均粒径Ｒおよび面積割合を測定した。
　その結果を、表１８および表１９に示す。 For the hard coating layers of the inventive coated tools 21-30 and comparative coated tools 21-30 , the average Al content ratio X avg , the average C content ratio Y was determined using the same method as shown in Example 1. avg was measured.
Further, using a method similar to the method shown in Example 1, the period of periodic concentration change of Ti and Al existing in the cubic crystal grains, the average of the maximum value of x and the minimum value of the concentration change The average difference Δx, and the crystal structure, average grain size R, and area ratio of the hexagonal fine crystal grains present at the grain boundaries of the individual crystal grains having the NaCl-type face-centered cubic structure were measured.
The results are shown in Table 18 and Table 19.
Figure JPOXMLDOC01-appb-T000017
Figure JPOXMLDOC01-appb-T000017
Figure JPOXMLDOC01-appb-T000018
Figure JPOXMLDOC01-appb-T000018
Figure JPOXMLDOC01-appb-T000019
Figure JPOXMLDOC01-appb-T000019
　つぎに、各種の被覆工具をいずれも工具鋼製バイトの先端部に固定治具にてネジ止めした状態で、本発明被覆工具２１～３０、比較被覆工具２１～３０について、以下に示す、鋳鉄の乾式高速断続切削加工試験を実施し、切刃の逃げ面摩耗幅を測定した。
　工具基体：立方晶窒化ホウ素基超高圧焼結体、
　切削試験：　鋳鉄の乾式高速断続切削加工、
　被削材：　　ＪＩＳ・ＦＣＤ８００の長さ方向等間隔８本縦溝入り丸棒、
　切削速度：　３００ ｍ／ｍｉｎ、
　切り込み：　０．１　ｍｍ、
　送り：　０．２　ｍｍ／ｒｅｖ、
　切削時間：　３分、
　表２０に、前記切削試験の結果を示す。 Next, the cast irons shown below for the inventive coated tools 21 to 30 and the comparative coated tools 21 to 30 with all the various coated tools screwed to the tip of the tool steel tool with a fixing jig. A dry high-speed intermittent cutting test was conducted, and the flank wear width of the cutting edge was measured.
Tool substrate: Cubic boron nitride-based ultra-high pressure sintered body,
Cutting test: Dry high speed intermittent cutting of cast iron,
Work material: JIS / FCD800 lengthwise equally spaced round bars with 8 vertical grooves,
Cutting speed: 300 m / min,
Cutting depth: 0.1 mm,
Feed: 0.2 mm / rev,
Cutting time: 3 minutes
Table 20 shows the results of the cutting test.
Figure JPOXMLDOC01-appb-T000020
Figure JPOXMLDOC01-appb-T000020
　表９、表１５および表２０に示される結果から、本発明の被覆工具は、硬質被覆層を構成するＡｌとＴｉの複合窒化物または複合炭窒化物層を構成するＮａＣｌ型の面心立方構造の結晶粒内において、工具基体表面に平行な面となす角度が３０度以内の方向に、該ＴｉとＡｌの周期的濃度変化が存在することで、切削加工時の剪断力に対する緩衝作用が働くために、クラックの伝播・進展が抑制されて、靱性が向上する。
　したがって、切れ刃に断続的・衝撃的高負荷が作用する高速断続切削加工に用いた場合でも、耐チッピング性、耐欠損性にすぐれ、その結果、長期の使用に亘ってすぐれた耐摩耗性が発揮される。 From the results shown in Table 9, Table 15, and Table 20, the coated tool of the present invention has a face-centered cubic structure of NaCl type that constitutes a composite nitride of Al and Ti or a composite carbonitride layer that constitutes a hard coating layer. In the crystal grains, a periodic concentration change of Ti and Al is present in a direction within 30 degrees with respect to the plane parallel to the tool base surface, so that a buffering action against a shearing force during cutting works. For this reason, propagation and progress of cracks are suppressed, and toughness is improved.
Therefore, even when used for high-speed intermittent cutting where intermittent and impactful high loads act on the cutting edge, it has excellent chipping resistance and chipping resistance, resulting in excellent wear resistance over a long period of use. Demonstrated.
　これに対して、硬質被覆層を構成するＡｌとＴｉの複合窒化物または複合炭窒化物層を構成するＮａＣｌ型の面心立方構造の結晶粒内に、本発明で規定する周期的な濃度変化が存在していない比較被覆工具については、高熱発生を伴い、しかも、切れ刃に断続的・衝撃的高負荷が作用する高速断続切削加工に用いた場合、チッピング、欠損等の発生により短時間で寿命にいたることが明らかである。 On the other hand, in the crystal grains of the NaCl-type face-centered cubic structure constituting the composite nitride of Al and Ti or the composite carbonitride layer constituting the hard coating layer, the periodic concentration change defined in the present invention In comparison coated tools that do not exist, high heat generation occurs, and when used for high-speed intermittent cutting where intermittent and impactful high loads act on the cutting edge, chipping, chipping, etc. can cause a short time. It is clear that it has reached the end of its life.
　前述のように、本発明の被覆工具は、合金鋼、鋳鉄、ステンレス鋼等の高速断続切削加工ばかりでなく、各種の被削材の被覆工具として用いることができ、しかも、長期の使用に亘ってすぐれた耐チッピング性を発揮するものであるから、切削装置の高性能化並びに切削加工の省力化および省エネ化、さらに低コスト化に十分満足に対応できるものである。 As described above, the coated tool of the present invention can be used as a coated tool for various work materials as well as high-speed intermittent cutting of alloy steel, cast iron, stainless steel, etc. Since it exhibits excellent chipping resistance, it can satisfactorily meet the demands for higher performance of the cutting device, labor saving and energy saving of cutting, and cost reduction.

Claims (7)

  1. 　炭化タングステン基超硬合金、炭窒化チタン基サーメットまたは立方晶窒化ホウ素基超高圧焼結体のいずれかで構成された工具基体の表面に、硬質被覆層が設けられた表面被覆切削工具において、
    （ａ）前記硬質被覆層は、平均層厚１～２０μｍのＴｉとＡｌの複合窒化物または複合炭窒化物層を少なくとも含み、
    （ｂ）前記複合窒化物または複合炭窒化物層は、ＮａＣｌ型の面心立方構造を有する複合窒化物または複合炭窒化物の結晶粒を少なくとも含み、
    （ｃ）前記複合窒化物または複合炭窒化物層を、工具基体の表面と垂直な任意の断面から分析した場合、前記ＮａＣｌ型の面心立方構造を有する結晶粒内には、ＴｉとＡｌの周期的な濃度変化が存在し、該ＴｉとＡｌの周期的な濃度変化のうちで濃度変化の周期が最小になる方向を求めたとき、該濃度変化の周期が最小になる方向と工具基体表面とのなす角が３０度以内であるようなＮａＣｌ型の面心立方構造を有する結晶粒が少なくとも存在することを特徴とする表面被覆切削工具。     In a surface-coated cutting tool in which a hard coating layer is provided on the surface of a tool base composed of any of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, or cubic boron nitride-based ultrahigh-pressure sintered body,
    (A) The hard coating layer includes at least a composite nitride or composite carbonitride layer of Ti and Al having an average layer thickness of 1 to 20 μm,
    (B) The composite nitride or composite carbonitride layer includes at least crystal grains of composite nitride or composite carbonitride having a NaCl type face-centered cubic structure,
    (C) When the composite nitride or composite carbonitride layer is analyzed from an arbitrary cross section perpendicular to the surface of the tool base, the crystal grains having the NaCl-type face-centered cubic structure include Ti and Al. When there is a periodic concentration change, and the direction in which the concentration change cycle is minimized among the periodic concentration changes of Ti and Al, the direction in which the concentration change cycle is minimized and the tool base surface A surface-coated cutting tool characterized in that at least crystal grains having an NaCl-type face-centered cubic structure with an angle of 30 degrees or less are present.
  2. 　前記複合窒化物または複合炭窒化物層は、その組成を、
    　組成式：（Ｔｉ１－ｘＡｌｘ）（ＣｙＮ１－ｙ）
    　で表した場合、ＡｌのＴｉとＡｌの合量に占める平均含有割合ＸａｖｇおよびＣのＣとＮの合量に占める平均含有割合Ｙａｖｇ（但し、Ｘａｖｇ、Ｙａｖｇはいずれも原子比）が、それぞれ、０．４０≦Ｘａｖｇ≦０．９５、０≦Ｙａｖｇ≦０．００５を満足であることを特徴とする請求項１に記載の表面被覆切削工具。     The composite nitride or composite carbonitride layer has its composition
    Composition formula: (Ti 1-x Al x ) (C y N 1-y )
    The average content ratio X avg in the total amount of Ti and Al in Al and the average content ratio Y avg in the total amount of C and N in C (where X avg and Y avg are both atomic ratios) Satisfying 0.40 ≦ X avg ≦ 0.95 and 0 ≦ Y avg ≦ 0.005, respectively.
  3. 　前記複合窒化物または複合炭窒化物層の前記断面からの観察において、前記ＴｉとＡｌの周期的な濃度変化が存在し、かつ、ＴｉとＡｌの周期的な濃度変化のうちで濃度変化の周期が最小になる方向と工具基体表面とのなす角が３０度以内であるようなＮａＣｌ型の面心立方構造を有する結晶粒が、前記複合窒化物または複合炭窒化物層の面積に占める割合は、４０面積％以上であることを特徴とする請求項１または請求項２に記載の表面被覆切削工具。 In the observation of the composite nitride or composite carbonitride layer from the cross section, there is a periodic concentration change of Ti and Al, and among the periodic concentration changes of Ti and Al, the concentration change period The ratio of the crystal grains having a NaCl-type face-centered cubic structure in which the angle formed between the direction in which the angle is minimum and the tool base surface is within 30 degrees to the area of the composite nitride or composite carbonitride layer is The surface-coated cutting tool according to claim 1, wherein the surface-coated cutting tool is 40 area% or more.
  4. 　前記複合窒化物または複合炭窒化物層中のＴｉとＡｌの周期的な濃度変化が存在し、かつ、ＴｉとＡｌの周期的な濃度変化のうちで濃度変化の周期が最小になる方向と工具基体表面とのなす角が３０度以内であるようなＮａＣｌ型の面心立方構造を有する結晶粒において、ＴｉとＡｌの周期的な濃度変化の周期は１～１０ｎｍであり、かつ、周期的に変化するＡｌの含有割合ｘの極大値の平均と極小値の平均の差は０．０１～０．１であることを特徴とする請求項１乃至請求項３のいずれか一項に記載の表面被覆切削工具。 A tool and a direction in which a periodic concentration change of Ti and Al in the composite nitride or composite carbonitride layer exists, and a periodicity of the concentration change among the periodic concentration changes of Ti and Al is minimized. In crystal grains having an NaCl type face-centered cubic structure where the angle formed with the substrate surface is within 30 degrees, the periodic concentration change period of Ti and Al is 1 to 10 nm, and periodically The surface according to any one of claims 1 to 3, wherein the difference between the average of the maximum value and the average of the minimum value of the changing Al content ratio x is 0.01 to 0.1. Coated cutting tool.
  5. 　前記複合窒化物または複合炭窒化物層について、該層の前記断面方向から観察した場合に、複合窒化物または複合炭窒化物層内のＮａＣｌ型の面心立方構造を有する個々の結晶粒の粒界部に、六方晶構造を有する微粒結晶粒が存在し、該微粒結晶粒の存在する面積割合が５面積％以下であり、該微粒結晶粒の平均粒径Ｒが０．０１～０．３μｍであることを特徴とする請求項１乃至請求項４のいずれか一項に記載の表面被覆切削工具。 When the composite nitride or composite carbonitride layer is observed from the cross-sectional direction of the layer, grains of individual crystal grains having a NaCl-type face-centered cubic structure in the composite nitride or composite carbonitride layer There are fine crystal grains having a hexagonal crystal structure at the boundary, the area ratio of the fine crystal grains is 5% by area or less, and the average grain size R of the fine crystal grains is 0.01 to 0.3 μm. The surface-coated cutting tool according to any one of claims 1 to 4, wherein
  6. 　前記工具基体と前記ＴｉとＡｌの複合窒化物または複合炭窒化物層の間に、Ｔｉの炭化物層、窒化物層、炭窒化物層、炭酸化物層および炭窒酸化物層のうちの１層または２層以上のＴｉ化合物層からなり、０．１～２０μｍの合計平均層厚を有する下部層が存在することを特徴とする請求項１乃至請求項５のいずれか一項に記載の表面被覆切削工具。 One layer of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride oxide layer between the tool base and the composite nitride or composite carbonitride layer of Ti and Al The surface coating according to any one of claims 1 to 5, wherein there is a lower layer comprising two or more Ti compound layers and having a total average layer thickness of 0.1 to 20 µm. Cutting tools.
  7. 　前記複合窒化物または複合炭窒化物層の上部に、少なくとも酸化アルミニウム層を含む上部層が１～２５μｍの合計平均層厚で形成されていることを特徴とする請求項１乃至請求項６のいずれか一項に記載の表面被覆切削工具。  7. The upper layer including at least an aluminum oxide layer is formed on the composite nitride or composite carbonitride layer at a total average layer thickness of 1 to 25 μm. The surface-coated cutting tool according to claim 1.
PCT/JP2016/065396 2015-05-26 2016-05-25 Surface-coated cutting tool with rigid coating layer exhibiting excellent chipping resistance WO2016190332A1 (en)

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KR1020177035979A KR20180011148A (en) 2015-05-26 2016-05-25 Surface-coated cutting tool with rigid coating layer exhibiting excellent chipping resistance
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