JP2018034237A

JP2018034237A - Surface-coated cutting tool

Info

Publication number: JP2018034237A
Application number: JP2016168782A
Authority: JP
Inventors: 田中　耕一; Koichi Tanaka; 耕一田中; 峻佐藤; Shun Sato; 強大上; Tsutomu Ogami; 一宮　夏樹; Natsuki Ichinomiya; 夏樹一宮; 達生橋本; Tatsuo Hashimoto
Original assignee: Mitsubishi Materials Corp
Current assignee: Mitsubishi Materials Corp
Priority date: 2016-08-31
Filing date: 2016-08-31
Publication date: 2018-03-08

Abstract

PROBLEM TO BE SOLVED: To provide a surface-coated cutting tool simultaneously exerting excellent crack resistance and wear resistance in high-speed intermittent cutting of a hardened steel.SOLUTION: In an objective surface-coated cutting tool, a composition-modulated structure in which the component concentrations of Cr, Ni and Zr change periodically along a layer thickness direction is formed in the (Al,Cr,Si,Ni,Zr)N layer having an average composition satisfying a compositional formula: (AlCrSiNiZr)N (here, in an atomic ratio, 0.15≤a≤0.40, 0.05≤b≤0.20, 0.002≤c≤0.02 and 0≤d≤0.02). The Cr concentration, Crmax at the maximum content point of a Cr component is a<Crmax≤1.30a, and that concentration, Crmin at the minimum content point of the Cr component is 0.50a≤Crmin<a. Besides, (c/a)/(c/a) is 0.7 or more but 1.3 or less in a whole layer thickness direction when defining the compositions of Ni and Cr at an optional measurement point z along the layer thickness direction as cand a, respectively.SELECTED DRAWING: Figure 2

Description

この発明は、焼き入れ鋼等の高硬度鋼の高速断続切削加工において、硬質被覆層がすぐれた耐摩耗性と耐クラック性を発揮し、長期の使用にわた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。 This invention is a surface-coated cutting that exhibits excellent wear resistance and crack resistance in high-speed intermittent cutting of hardened steel such as hardened steel, and exhibits excellent cutting performance over a long period of use. The present invention relates to a tool (hereinafter referred to as a coated tool).

一般に、被覆工具として、各種の鋼や鋳鉄などの被削材の旋削加工や平削り加工にバイトの先端部に着脱自在に取り付けて用いられるスローアウエイチップ、前記被削材の穴あけ切削加工などに用いられるドリルやミニチュアドリル、前記被削材の面削加工や溝加工、肩加工などに用いられるエンドミル、前記被削材の歯形の歯切加工などに用いられるソリッドホブ、ピニオンカッタなどが知られている。
そして、被覆工具の切削性能改善を目的として、従来から、数多くの提案がなされている。 In general, as a coated tool, for throwing inserts that can be used detachably attached to the tip of a cutting tool for turning and planing of various materials such as steel and cast iron, and for drilling and cutting the work material Known drills and miniature drills, end mills used for chamfering and grooving, shoulder processing, etc. of the work material, solid hob, pinion cutter used for gear cutting of the tooth profile of the work material, etc. Yes.
Many proposals have been made for the purpose of improving the cutting performance of the coated tool.

例えば、特許文献１に示すように、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）基サーメット等の工具基体の表面に、Ｃｒ、Ａｌ及びＳｉを主成分とする金属成分と、Ｃ、Ｎ、Ｏ、Ｂから選択される少なくとも１種以上の元素とから構成される立方晶構造の硬質層を１層以上被覆することにより、耐欠損性、耐摩耗性を改善した被覆工具が提案されている。 For example, as shown in Patent Document 1, Cr, Al, and Si are formed on the surface of a tool base such as tungsten carbide (hereinafter referred to as WC) -based cemented carbide, titanium carbonitride (hereinafter referred to as TiCN) -based cermet. By covering one or more hard layers having a cubic structure composed of a metal component as a main component and at least one element selected from C, N, O, and B, chipping resistance, Coated tools with improved wear have been proposed.

また、特許文献２には、Ｃｒ_1-x-y-zＡｌ_x（Ｎｉ_1-aＺｒ_a）_yＭ_zで表される組成（但し、Ｍは、Ｔｉ、Ｎｂ、Ｓｉ、Ｂ、Ｗ及びＶから選ばれる少なくとも１種の元素、０．５≦ｘ≦０．８、０．０１≦ｙ≦０．３５、０≦ｚ≦０．２、０．５１≦ｘ＋ｙ＋ｚ＜１、０．２≦ａ≦０．５）を有し、相対密度が９５％以上であるターゲットを用いて、窒化物、炭化物又は炭窒化物を含む硬質被膜を形成することにより、被覆工具の耐摩耗性及び密着性を改善することが提案されている。 Patent Document 2 discloses _a composition represented by Cr _1-xyz Al _x (Ni _1-a Zr _a ) _y M _z (where M is selected from Ti, Nb, Si, B, W, and V). At least one element, 0.5 ≦ x ≦ 0.8, 0.01 ≦ y ≦ 0.35, 0 ≦ z ≦ 0.2, 0.51 ≦ x + y + z <1, 0.2 ≦ a ≦ 0. 5) and improving the wear resistance and adhesion of the coated tool by forming a hard film containing nitride, carbide or carbonitride using a target having a relative density of 95% or more. Has been proposed.

さらに、特許文献３には、工具基体表面に、ＣｒとＡｌの複合窒化物からなる硬質被覆層を物理蒸着してなる被覆工具において、硬質被覆層を、層厚方向にそって、Ａｌ最高含有点とＡｌ最低含有点とが所定間隔をおいて交互に繰り返し存在し、かつ前記両点間でＡｌ含有量が連続的に変化する成分濃度分布構造を有し、さらに、上記Ａｌ最高含有点が、組成式：（Ｃｒ_１−ＸＡｌ_Ｘ）Ｎ（ただし、原子比で、Ｘは０．４０〜０．６０を示す）を満足し、また、上記Ａｌ最低含有点が、組成式：（Ｃｒ_１−ＹＡｌ_Ｙ）Ｎ（ただし、原子比で、Ｙは０．０５〜０．３０を示す）を満足し、かつ、隣り合う上記Ａｌ最高含有点とＡｌ最低含有点の間隔が、０．０１〜０．１μｍである硬質被覆層とすることにより、重切削加工条件で硬質被覆層がすぐれた耐チッピング性を発揮すると記載されている。 Furthermore, in Patent Document 3, in a coated tool formed by physically vapor-depositing a hard coating layer made of a composite nitride of Cr and Al on the surface of a tool base, the hard coating layer contains the highest Al along the layer thickness direction. Points and Al minimum content points are alternately present repeatedly at a predetermined interval, and the Al content is continuously varied between the two points, and the Al maximum content point is , Composition formula: (Cr _1-X Al _X ) N (wherein X is 0.40 to 0.60 in atomic ratio), and the above-mentioned Al minimum content point is the composition formula: (Cr _1-Y Al _Y ) N (wherein Y represents 0.05 to 0.30 in atomic ratio), and the distance between the adjacent Al highest content point and Al minimum content point adjacent to each other is 0. Hard coating under heavy cutting conditions by using a hard coating layer of 01-0.1 μm It is described that the layer exhibits excellent chipping resistance.

特許第３７８１３７４号公報Japanese Patent No. 3781374 特開２０１３−３２５７８号公報JP 2013-32578 A 特開２００４−５０３８１号公報JP 2004-50381A

近年の切削加工装置の高性能化はめざましく、一方で切削加工に対する省力化および省エネ化、さらに低コスト化の要求は強く、これに伴い、切削加工はますます高速化・高能率化の傾向にあるが、上記従来の被覆工具においては、これを鋼や鋳鉄などの通常の切削条件での切削加工に用いた場合には、特段の問題は生じないが、これを、例えば、ＳＫＤ１１やＳＫＤ５１等の焼き入れ鋼の高速ミーリング加工のような、高熱発生を伴い、しかも、切刃に対して衝撃的・断続的な高負荷がかかる高速断続切削加工に用いた場合には、クラックの発生・伝播を抑制することができず、また、摩耗進行も促進されるため、比較的短時間で使用寿命に至るのが現状である。 In recent years, the performance of cutting machines has been dramatically improved, while there is a strong demand for labor saving, energy saving, and cost reduction for cutting, and as a result, cutting has become a trend toward higher speed and higher efficiency. However, in the above-described conventional coated tool, when this is used for cutting under normal cutting conditions such as steel or cast iron, no particular problem occurs. For example, SKD11, SKD51, etc. Crack generation and propagation when used in high-speed intermittent cutting that involves high heat generation, such as high-speed milling of hardened steel, and that also imposes a shocking and intermittent high load on the cutting edge. In the present situation, it is impossible to suppress the wear and the progress of wear is promoted, so that the service life is reached in a relatively short time.

例えば、特許文献１に示される従来被覆工具においては、硬質被覆層を構成する（Ａｌ，Ｃｒ，Ｓｉ）Ｎ層のＡｌ成分は高温硬さ、同Ｃｒ成分は高温靭性、高温強度を向上させると共に、ＡｌおよびＣｒが共存含有した状態で高温耐酸化性を向上させ、さらに同Ｓｉ成分は耐熱塑性変形性を向上させる作用があるが、高熱発生を伴い、しかも、切刃に対して衝撃的・断続的な高負荷がかかる切削条件においては、チッピング、欠損等の発生を避けることはできず、例えば、Ｃｒ含有割合を増加することにより高温靭性、高温強度の改善を図ろうとしても、相対的なＡｌ含有割合の減少によって、耐摩耗性が低下してしまうため、（Ａｌ，Ｃｒ，Ｓｉ）Ｎ層からなる硬質被覆層における耐摩耗性と耐クラック性の両立を図るには自ずから限界がある。
また、特許文献２に示される従来被覆工具においては、耐摩耗性が向上、工具基体に対する硬質被覆層の密着性の改善はあるものの、切刃に対して衝撃的・断続的な高負荷がかかる高速断続切削加工条件においては、硬質被覆層の発生したクラックが層を貫通して進展するため、クラックの発生を原因とするチッピング、欠損が発生しやすく、工具寿命は短命である。
さらに、特許文献３に示される従来被覆工具においては、硬質被覆層中に繰り返し成分濃度が変化する組成変調構造を形成し、高温硬さと耐熱性はＡｌ最高含有点（Ｃｒ最低含有点に相当）で担保し、一方、硬質被覆層の強度は、Ａｌ最高含有点（Ｃｒ最低含有点に相当）に隣接するＡｌ最低含有点（Ｃｒ最低含有点に相当）で確保することにより、耐チッピング性と耐摩耗性を確保しているが、通常の鋼や合金鋼、鋳鉄の切削加工ではある程度の効果は得られるものの、高硬度材（例えば、ＨＲＣ６０以上）の切削加工においては、切れ刃に作用する衝撃的・断続的な高負荷により、耐摩耗性、耐クラック性が十分であるとはいえない。 For example, in the conventional coated tool disclosed in Patent Document 1, the Al component of the (Al, Cr, Si) N layer constituting the hard coating layer improves high-temperature hardness, and the Cr component improves high-temperature toughness and high-temperature strength. In the coexistence of Al and Cr, the high-temperature oxidation resistance is improved, and further, the Si component has the effect of improving the heat-resistant plastic deformation property. Under cutting conditions that require intermittent high loads, chipping, chipping, etc. cannot be avoided. For example, by increasing the Cr content ratio, even if trying to improve high temperature toughness and high temperature strength, relative Since the wear resistance decreases due to a significant decrease in the Al content ratio, there is a limit to achieving both wear resistance and crack resistance in a hard coating layer made of an (Al, Cr, Si) N layer. That.
Further, in the conventional coated tool disclosed in Patent Document 2, although wear resistance is improved and adhesion of the hard coating layer to the tool base is improved, impact and intermittent high loads are applied to the cutting edge. Under high-speed interrupted cutting conditions, the crack generated by the hard coating layer propagates through the layer, so that chipping and chipping due to the occurrence of the crack are likely to occur, and the tool life is short.
Furthermore, in the conventional coated tool shown in Patent Document 3, a composition modulation structure in which the component concentration is repeatedly changed is formed in the hard coating layer, and the high temperature hardness and heat resistance are the highest Al content point (corresponding to the lowest Cr content point). On the other hand, by ensuring the strength of the hard coating layer at the Al minimum content point (corresponding to the Cr minimum content point) adjacent to the Al maximum content point (corresponding to the Cr minimum content point), Abrasion resistance is ensured, but some effects can be obtained by cutting ordinary steel, alloy steel, and cast iron, but it works on the cutting edge in cutting hard materials (for example, HRC 60 or higher). It cannot be said that the wear resistance and crack resistance are sufficient due to impact and intermittent high loads.

そこで、本発明者等は、上述の観点から、焼き入れ鋼の高速ミーリング加工のような、高熱発生を伴い、しかも、切刃に対して衝撃的・断続的な高負荷が作用する断続切削加工条件下で、硬質被覆層がすぐれた耐摩耗性と耐クラック性を両立し得る被覆工具を開発すべく、硬質被覆層を構成する成分および層構造に着目し研究を行った結果、以下のような知見を得た。 In view of the above, the present inventors, from the above-mentioned viewpoint, are accompanied by high heat generation, such as high-speed milling of hardened steel, and in addition, an intermittent cutting process in which a shocking and intermittent high load acts on the cutting blade. In order to develop a coated tool that can achieve both wear resistance and crack resistance with excellent hard coating layer under the conditions, as a result of research focusing on the components and layer structure that make up the hard coating layer, the following results were obtained. I got a good knowledge.

即ち、本発明者は、（Ａｌ，Ｃｒ）Ｎ層からなる硬質被覆層の成分として、Ｎｉを含有させることによって、切削負荷応力低減効果を図り、また、Ｚｒを含有させることによって、硬度の向上を図り、さらに、Ｓｉを含有させることによって耐酸化性の向上を図るとともに、硬質被覆層を構成する成分の濃度（特に、Ｃｒ成分の濃度）が層の層厚方向に沿って周期的に変化する組成変調構造をもち、さらにＣｒ成分の濃度とＮｉ成分の濃度の周期的な変化が同位相である特徴をもった層として構成することによって、硬質被覆層は、耐クラック性と耐摩耗性の両特性を相兼ね備えるようになることを見出した。さらに、Ｃｒ成分の濃度とＮｉ成分の濃度とＺｒ成分の濃度の周期的な変化が同位相である特徴をもった層として構成することによって、硬質被覆層は、更なる耐クラック性と耐摩耗性の両特性を相兼ね備えるようになることを見出した。
そして、前記硬質被覆層を備えた被覆工具は、高熱発生を伴い、しかも、切刃に対して衝撃的・断続的な高負荷が作用する高速断続切削加工（例えば、例えば、焼き入れ鋼の高速ミーリング加工）に供した場合であっても、すぐれた耐クラック性とともに、長期の使用にわたって、すぐれた耐摩耗性を発揮することを見出したのである。 That is, the present inventor can reduce the cutting load stress by adding Ni as a component of the hard coating layer composed of the (Al, Cr) N layer, and improve the hardness by adding Zr. Furthermore, by adding Si, the oxidation resistance is improved, and the concentration of the components constituting the hard coating layer (especially the concentration of the Cr component) periodically changes along the layer thickness direction of the layer. The hard coating layer has a crack resistance and wear resistance by being composed as a layer having a composition modulation structure that has the same phase of the cyclic change of the Cr component concentration and the Ni component concentration. It has been found that both of these characteristics are combined. Furthermore, the hard coating layer is further improved in crack resistance and wear resistance by constituting as a layer having the characteristics that the cyclic change of the Cr component concentration, the Ni component concentration and the Zr component concentration are in phase. It has been found that both characteristics of sex are combined.
And the coated tool provided with the said hard coating layer is accompanied by high heat generation, and also the high-speed intermittent cutting process (for example, high-speed of hardened steel, for example) that an impact and intermittent high load acts on a cutting blade. It has been found that even when it is subjected to milling, it exhibits excellent wear resistance over a long period of use as well as excellent crack resistance.

この発明は、上記の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あるいは立方晶窒化硼素焼結体のいずれかからなる工具基体の表面に、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０．５〜８．０μｍの立方晶構造のＡｌとＣｒとＳｉとＮｉとＺｒの複合窒化物層を少なくとも含み、
（ｂ）前記複合窒化物層は、
組成式：（Ａｌ_{１−ａ−ｂ−ｃ−ｄ}Ｃｒ_ａＳｉ_ｂＮｉ_ｃＺｒ_ｄ）Ｎで表した場合、
０．１５≦ａ≦０．４０、０．０５≦ｂ≦０．２０、０．００２≦ｃ≦０．０２、０≦ｄ≦０．０２（ただし、ａ、ｂ、ｃ、ｄはいずれも原子比）を満足する平均組成を有し、
（ｃ）前記複合窒化物層は、層厚方向に沿ってＣｒ成分濃度が周期的に変化する組成変調構造とＮｉ成分濃度が周期的に変化する組成変調構造を有し、
（ｄ）前記組成変調構造におけるＣｒ成分濃度の周期的な変化は、Ｃｒ成分の最高含有点とＣｒ成分の最低含有点が５ｎｍ〜１００ｎｍの間隔で繰り返され、
（ｅ）前記Ｃｒ成分の最高含有点におけるＣｒ成分の濃度Ｃｒｍａｘは、
ａ＜Ｃｒｍａｘ≦１．３０ａの範囲内であり、
一方、前記Ｃｒ成分の最低含有点におけるＣｒ成分の濃度Ｃｒｍｉｎは、
０．５０ａ≦Ｃｒｍｉｎ＜ａの範囲内であり(ただし、ａは、前記（ｂ）の組成式におけるＣｒの平均組成ａを示す)、
（ｆ）前記組成変調構造におけるＮｉ成分濃度の周期的な変化は、Ｎｉ成分の最高含有点とＮｉ成分の最低含有点が５ｎｍ〜１００ｎｍの間隔で繰り返され、
（ｇ）層厚方向に沿った任意の測定点ｚにおけるＮｉの組成をｃ_ｚ、Ｃｒの組成をａ_ｚとした時、ａ_ｚに対するｃ_ｚの比の値（ｃ_ｚ／ａ_ｚ）を、前記複合窒化物層におけるＣｒの平均組成ａに対するＮｉの平均組成ｃの比の値（ｃ／ａ）で除した値（ｃ_ｚ／ａ_ｚ）／（ｃ／ａ）が、層厚方向全体にわたって０．７≦（ｃ_ｚ／ａ_ｚ）／（ｃ／ａ）≦１．３の範囲に存在することを特徴とする表面被覆切削工具。
（２）前記（１）に記載の表面被覆切削工具において、前記複合窒化物層中のＺｒの含有割合ｄは、０．００２≦ｄ≦０．０２を満足し、
（ａ）前記複合窒化物層は、層厚方向に沿ってＺｒ成分濃度が周期的に変化する組成変調構造を有し、
（ｂ）前記組成変調構造におけるＺｒ成分濃度の周期的な変化は、Ｚｒ成分の最高含有点とＺｒ成分の最低含有点が５ｎｍ〜１００ｎｍの間隔で繰り返され、
（ｃ）層厚方向に沿った任意の測定点ｚにおけるＺｒの組成をｄ_ｚ、Ｃｒの組成をａ_ｚとした時、ａ_ｚに対するｄ_ｚの比の値（ｄ_ｚ／ａ_ｚ）を、前記複合窒化物層におけるＣｒの平均組成ａに対するＺｒの平均組成ｄの比の値（ｄ／ａ）で除した値（ｄ_ｚ／ａ_ｚ）／（ｄ／ａ）が、層厚方向全体にわたって０．７≦（ｄ_ｚ／ａ_ｚ）／（ｄ／ａ）≦１．３の範囲に存在することを特徴とする前記（１）に記載の表面被覆切削工具。」
を特徴とするものである。 This invention has been made based on the above findings,
“(1) In a surface-coated cutting tool 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 sintered body,
(A) The hard coating layer includes at least a composite nitride layer of Al, Cr, Si, Ni, and Zr having a cubic structure with an average layer thickness of 0.5 to 8.0 μm,
(B) The composite nitride layer is
_Formula: when expressed in _{(Al 1-a-b-} c-d Cr a Si b Ni c Zr d) N,
0.15 ≦ a ≦ 0.40, 0.05 ≦ b ≦ 0.20, 0.002 ≦ c ≦ 0.02, 0 ≦ d ≦ 0.02 (where a, b, c, and d are all Having an average composition satisfying (atomic ratio),
(C) The composite nitride layer has a composition modulation structure in which the Cr component concentration periodically changes along the layer thickness direction and a composition modulation structure in which the Ni component concentration periodically changes.
(D) The periodic change of the Cr component concentration in the composition modulation structure is repeated at intervals of 5 nm to 100 nm between the highest content point of the Cr component and the lowest content point of the Cr component,
(E) The concentration Crmax of the Cr component at the highest content point of the Cr component is:
a <Crmax ≦ 1.30a.
On the other hand, the concentration Crmin of the Cr component at the minimum content point of the Cr component is
0.50a ≦ Crmin <a (where a represents the average composition a of Cr in the composition formula (b)),
(F) The periodic change of the Ni component concentration in the composition modulation structure is repeated at intervals of 5 nm to 100 nm between the highest content point of the Ni component and the lowest content point of the Ni component,
(G) a composition of Ni at any measuring point z along the thickness direction _c z, when a composition of Cr was _{a z,} the ratio of _{c z} for _{a z} value _(c _z / _a z), The value (c _z / a _z ) / (c / a) obtained by dividing the ratio (c / a) of the average composition c of Ni to the average composition a of Cr in the composite nitride layer over the entire layer thickness direction. A surface-coated cutting tool characterized by being in a range of 0.7 ≦ (c _z / a _z ) / (c / a) ≦ 1.3.
(2) In the surface-coated cutting tool according to (1), the content ratio d of Zr in the composite nitride layer satisfies 0.002 ≦ d ≦ 0.02.
(A) The composite nitride layer has a composition modulation structure in which the Zr component concentration changes periodically along the layer thickness direction,
(B) The periodic change in the Zr component concentration in the composition modulation structure is repeated at intervals of 5 nm to 100 nm between the highest content point of the Zr component and the lowest content point of the Zr component,
The composition of Zr at any measuring point z along the (c) layer thickness direction _d z, when a composition of Cr was _{a z,} the ratio of _{d z} for _{a z} value _(d _z / _a z), The value (d _z / a _z ) / (d / a) divided by the value (d / a) of the ratio of the average composition d of Zr to the average composition a of Cr in the composite nitride layer is the entire layer thickness direction. It exists in the range of 0.7 <= ( _dz / _az ) / (d / a) <= 1.3, The surface-coated cutting tool as described in said (1) characterized by the above-mentioned. "
It is characterized by.

つぎに、この発明の被覆工具について、詳細に説明する。 Next, the coated tool of the present invention will be described in detail.

硬質被覆層：
本発明では、硬質被覆層として、少なくとも、ＡｌとＣｒとＳｉとＮｉとＺｒの複合窒化物層（以下、「（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層」で示す場合もある。）を備えるが、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層におけるＡｌ成分には高温硬さ、同Ｃｒ成分には高温靭性、高温強度を向上させると共に、ＡｌおよびＣｒが共存含有した状態で高温耐酸化性を向上させ、さらに同Ｓｉ成分には耐熱塑性変形性性を向上させる作用があり、また、Ｎｉ成分には、切削負荷抵抗低減作用があり、さらに、Ｚｒ成分には、硬度向上効果がある。 Hard coating layer:
In the present invention, as the hard coating layer, at least a composite nitride layer of Al, Cr, Si, Ni and Zr (hereinafter also referred to as “(Al, Cr, Si, Ni, Zr) N layer”). In the (Al, Cr, Si, Ni, Zr) N layer, the Al component improves high-temperature hardness, the Cr component improves high-temperature toughness and high-temperature strength, and contains Al and Cr together. The Si component has the effect of improving the high-temperature oxidation resistance, and the heat resistance plastic deformation property of the same Si component, the Ni component has the effect of reducing the cutting load resistance, and the Zr component has improved hardness. effective.

（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の平均組成：
前記（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層におけるＣｒの平均組成を示すａ値（原子比）がＡｌとＳｉとＮｉとＺｒの合量に占める割合で０．１５未満では、最低限必要とされる高温靭性、高温強度を確保することができないため、チッピング、欠損等の原因となるクラックの発生を抑制することができず、一方、同ａ値が０．４０を超えると、相対的なＡｌ含有割合の減少により、摩耗進行が促進することから、ａ値を０．１５〜０．４０と定めた。
また、Ｓｉの平均組成を示すｂ値（原子比）がＡｌとＣｒとＮｉとＺｒの合量に占める割合で０．０５未満では、耐酸化性の改善による耐摩耗性向上を期待することはできず、一方、同ｂ値が０．２０を超えると、耐摩耗性向上効果に低下傾向がみられるようになることから、ｂ値を０．０５〜０．２０と定めた。
また、Ｎｉの平均組成を示すｃ値（原子比）がＡｌとＣｒとＳｉとＺｒの合量に占める割合で０．００２未満では、切削負荷応力低減効果を期待することができず、一方、同ｃ値が０．０２を超えると、アークイオンプレーティング（以下、「ＡＩＰ」で示す。）装置によって（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層を成膜する際にパーティクルが発生しやすくなり、大きな衝撃的・機械的負荷がかかる切削加工において耐クラック性が低下することから、ｃ値を０．００２〜０．０２と定めた。
さらに、Ｚｒは、層中の成分として含有させた場合、硬度向上効果を有し、耐摩耗性を高めるが、ＡｌとＣｒとＳｉとＮｉの合量に占める割合で０．０２を超えると耐クラック性を低下させることになるので、Ｚｒの平均組成を示すｄ値（原子比）は０≦ｄ≦０．０２とする。
上記ａ、ｂ、ｃ、ｄについて、好ましい範囲は、それぞれ、０．１５≦ａ≦０．２５、０．０５≦ｂ≦０．１５、０．００５≦ｃ≦０．０１５、０．００２≦ｄ≦０．０２である。
なお、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層を構成する成分の総量に対するＮ成分の含有割合は、化学量論比である０．５０には限定されず、これと同等な効果が得られる範囲である０．４５以上０．６５以下の範囲であればよい。 Average composition of (Al, Cr, Si, Ni, Zr) N layer:
If the a value (atomic ratio) indicating the average composition of Cr in the (Al, Cr, Si, Ni, Zr) N layer is less than 0.15 in terms of the total amount of Al, Si, Ni and Zr, the minimum Since the required high-temperature toughness and high-temperature strength cannot be ensured, the occurrence of cracks that cause chipping, chipping, etc. cannot be suppressed. On the other hand, if the value a exceeds 0.40, The a value was determined to be 0.15 to 0.40 because the progress of wear was promoted by a decrease in the Al content.
Further, if the b value (atomic ratio) indicating the average composition of Si is less than 0.05 in the ratio of the total amount of Al, Cr, Ni, and Zr, it is expected to improve wear resistance by improving oxidation resistance. On the other hand, when the b value exceeds 0.20, the wear resistance improving effect tends to decrease, so the b value was set to 0.05 to 0.20.
Further, if the c value (atomic ratio) indicating the average composition of Ni is less than 0.002 in the proportion of the total amount of Al, Cr, Si and Zr, the cutting load stress reduction effect cannot be expected, When the c value exceeds 0.02, particles are generated when an (Al, Cr, Si, Ni, Zr) N layer is formed by an arc ion plating (hereinafter referred to as “AIP”) apparatus. The c value was determined to be 0.002 to 0.02 because the crack resistance is reduced in the cutting process that is easy and requires a large impact / mechanical load.
Further, when Zr is contained as a component in the layer, it has an effect of improving hardness and enhances wear resistance. However, if Zr exceeds 0.02 as a proportion of the total amount of Al, Cr, Si, and Ni, it is resistant. Since the cracking property is lowered, the d value (atomic ratio) indicating the average composition of Zr is set to 0 ≦ d ≦ 0.02.
Regarding a, b, c, and d, preferable ranges are 0.15 ≦ a ≦ 0.25, 0.05 ≦ b ≦ 0.15, 0.005 ≦ c ≦ 0.015, and 0.002 ≦, respectively. d ≦ 0.02.
Note that the content ratio of the N component to the total amount of the components constituting the (Al, Cr, Si, Ni, Zr) N layer is not limited to the stoichiometric ratio of 0.50, and an equivalent effect is obtained. What is necessary is just the range of 0.45 or more and 0.65 or less which is the range obtained.

（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の平均層厚：
前記（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層は、その平均層厚が０．５μｍ未満では、長期の使用にわたってすぐれた耐摩耗性を発揮することはできず、一方、その平均層厚が８．０μｍを超えると、チッピング、欠損等の原因となるクラックを発生しやすくなるので、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の平均層厚は、０．５〜８．０μｍと定めた。 Average layer thickness of (Al, Cr, Si, Ni, Zr) N layer:
The (Al, Cr, Si, Ni, Zr) N layer has an average layer thickness of less than 0.5 μm and cannot exhibit excellent wear resistance over a long period of use. When the thickness exceeds 8.0 μm, cracks that cause chipping, defects, etc. are likely to occur. Therefore, the average layer thickness of the (Al, Cr, Si, Ni, Zr) N layer is 0.5 to 8.0 μm. It was determined.

図１に、本発明の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層に形成される各成分の組成変調構造の一例を示すが、図１の（ａ）、（ｂ）のいずれにおいても、各成分の濃度は、層厚方向に沿って、最高含有点−最低含有点−最高含有点−最低含有点・・・と、所定の間隔を保って周期的な濃度変化を示している。ここでいう最高含有点、最低含有点について説明する。例としてＣｒについて説明するが、他の成分についても同様である。ここでいうＣｒの最高含有点とは、層厚方向に沿って測定した各測定点における各組成成分の濃度が、層全体の組成式（Ａｌ_{１−ａ−ｂ−ｃ−ｄ}Ｃｒ_ａＳｉ_ｂＮｉ_ｃＺｒ_ｄ）ＮにおけるＣｒ成分の濃度割合ａの値を連続して超えている部分における最大値を言い、ａの値を連続して超えている部分が複数ある場合は、それぞれの部分における最大値をそれぞれの部分における最高含有点と定義する。同様に、ここでいう最低含有点とは、層厚方向に沿って測定した各測定点における各組成成分の濃度が、層全体の組成式（Ａｌ_{１−ａ−ｂ−ｃ−ｄ}Ｃｒ_ａＳｉ_ｂＮｉ_ｃＺｒ_ｄ）Ｎにおけるａの値以下となる連続した部分における最小値を言い、連続してａの値以下となる部分が複数ある場合は、それぞれの部分における最小値をそれぞれの部分における最小含有点と定義する。この定義によれば、ａの値近傍での周期的な変化において、図１（ａ）に示すように、最高含有点と最低含有点が交互に出現する。
図１（ａ）には、本発明の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の、層厚方向に沿うＣｒ成分濃度、Ｎｉ成分濃度及びＺｒ成分濃度が周期的に変化する様子を示し、また、図１（ｂ）には、本発明の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の、層厚方向に沿うＡｌ成分濃度及びＳｉ成分濃度が周期的に変化する様子を示す。
図１の（ａ）、（ｂ）からもわかるように、Ｃｒ成分、Ｎｉ成分およびＺｒ成分は、同じ位相で周期的な濃度変化を示し、また、Ａｌ成分とＳｉ成分は、同じ位相で周期的な濃度変化を示す。謂うならば、Ｃｒ成分、Ｎｉ成分とＺｒ成分、また、Ａｌ成分とＳｉ成分は、それぞれ、ペアを組んで濃度変化し、組成変調構造を形成していることがわかる。 FIG. 1 shows an example of the composition modulation structure of each component formed in the (Al, Cr, Si, Ni, Zr) N layer of the present invention. In either of FIG. 1 (a) or (b) The concentration of each component indicates a periodic concentration change at a predetermined interval in the layer thickness direction, with a predetermined interval of highest content point-lowest content point-highest content point-lowest content point. Here, the maximum content point and the minimum content point will be described. Although Cr will be described as an example, the same applies to other components. The highest content point of Cr here means that the concentration of each composition component at each measurement point measured along the layer thickness direction is the composition formula of the entire layer (Al _1-a-b-cd Cr _a Si _b Ni _c Zr _d ) Indicates the maximum value in a portion that continuously exceeds the value of the concentration ratio a of the Cr component in N, and when there are a plurality of portions that continuously exceed the value of a, The maximum value is defined as the highest content point in each part. Similarly, the term “minimum content point” as used herein means that the concentration of each composition component at each measurement point measured along the layer thickness direction is the composition formula of the entire layer (Al _1-abbcd Cr _a Si _b Ni _c Zr _d ) N refers to the minimum value in a continuous portion that is less than or equal to the value of a. When there are a plurality of portions that are successively less than or equal to the value of a, the minimum value in each portion is It is defined as the minimum content point. According to this definition, in a periodic change in the vicinity of the value a, as shown in FIG. 1A, the highest content point and the lowest content point appear alternately.
FIG. 1A shows a state in which the Cr component concentration, the Ni component concentration, and the Zr component concentration along the thickness direction of the (Al, Cr, Si, Ni, Zr) N layer of the present invention periodically change. FIG. 1 (b) shows how the Al component concentration and the Si component concentration along the thickness direction of the (Al, Cr, Si, Ni, Zr) N layer of the present invention periodically change. Show.
As can be seen from FIGS. 1A and 1B, the Cr component, the Ni component, and the Zr component show periodic concentration changes in the same phase, and the Al component and the Si component have a period in the same phase. Concentration change. In other words, it can be seen that the Cr component, the Ni component and the Zr component, and the Al component and the Si component change in concentration in pairs to form a composition modulation structure.

Ｃｒ成分の組成変調におけるＣｒ最高含有点におけるＣｒ濃度：
図１（ａ）に示されたＣｒ成分の周期的な組成変調において、Ｃｒ最高含有点の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層におけるＣｒ成分は、層自体の強度を向上させ、耐クラック性を向上させる作用をもつが、Ｃｒ最高含有点におけるＣｒの含有割合を示すＣｒｍａｘが、１．３０ａ（ただし、ａの値は、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の組成式：（Ａｌ_{１−ａ−ｂ−ｃ−ｄ}Ｃｒ_ａＳｉ_ｂＮｉ_ｃＺｒ_ｄ）ＮにおけるＣｒの平均組成ａを示す）より大きくなると、相対的に、Ａｌ、Ｓｉ、Ｎｉ、Ｚｒの含有割合が減少するため、高硬度を有するＣｒ最低含有点が隣接して存在しても層全体としての耐熱性、耐摩耗性の低下は避けられず、一方、各Ｃｒ最高含有点における平均のＣｒの含有割合を示すＣｒｍａｘは、その定義により、ａ以下の値を取らないことから、各Ｃｒ最高含有点における平均Ｃｒ濃度を示すＣｒｍａｘの値は、ａを超え１．３０ａ以下と定めた。なお、Ｃｒｍａｘの値は、１．０３ａ≦Ｃｒｍａｘ≦１．２５ａを満足することが望ましい。 Cr concentration at the highest Cr content point in compositional modulation of Cr component:
In the periodic compositional modulation of the Cr component shown in FIG. 1 (a), the Cr component in the (Al, Cr, Si, Ni, Zr) N layer at the highest Cr content point improves the strength of the layer itself, Although it has the effect of improving crack resistance, the Crmax indicating the Cr content at the highest Cr content point is 1.30a (where the value of a is (Al, Cr, Si, Ni, Zr) N layer) Composition formula: (Al _1- abc _cd Cr _a Si _b Ni _c Zr _d ) The average composition a of Cr in N indicates a relatively larger content of Al, Si, Ni, Zr Since the ratio decreases, even if there are adjacent Cr minimum content points having high hardness, the heat resistance and wear resistance of the entire layer are inevitably lowered. On the other hand, the average Cr at each Cr maximum content point is unavoidable. Crmax indicating the content ratio of Therefore, since a value of a or less was not taken, the value of Crmax indicating the average Cr concentration at each Cr highest content point was determined to be greater than a and 1.30 a or less. The value of Crmax desirably satisfies 1.03a ≦ Crmax ≦ 1.25a.

Ｃｒ成分の組成変調におけるＣｒ最低含有点におけるＣｒ濃度：
前記のとおり、Ｃｒ最高含有点は相対的に高強度を有し、耐クラック性を向上させるが、その反面、相対的に硬度が小さく耐摩耗性に劣り、また耐熱性にも劣るものであるため、このＣｒ最高含有点の耐摩耗性不足、耐熱性不足を補うため、Ｃｒ含有割合を相対的に小さくし、これによって層全体としての耐摩耗性、耐熱性を向上させるＣｒ最低含有点を厚さ方向に交互に周期的に形成する。
したがって、Ｃｒ最低含有点におけるＣｒの含有割合を示すＣｒｍｉｎが、０．５０ａ（ただし、ａの値は、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の組成式：（Ａｌ_{１−ａ−ｂ−ｃ−ｄ}Ｃｒ_ａＳｉ_ｂＮｉ_ｃＺｒ_ｄ）ＮにおけるＣｒの平均組成ａを示す）より小さくなると、高強度を有するＣｒ最高含有点が隣接して存在しても層全体としての耐クラック性の低下は避けられず、一方、Ｃｒ最低含有点におけるＣｒの含有割合を示すＣｒｍｉｎは、その定義により、ａ以上の数値とならないことから、Ｃｒ最低含有点におけるＣｒ濃度を示すＣｒｍｉｎの値は、０．５０ａ以上ａ未満と定めた。なお、Ｃｒｍｉｎの値は、０．６５ａ≦Ｃｒｍｉｎ≦０．９５ａを満足することが望ましい。 Cr concentration at the lowest Cr content point in the compositional modulation of the Cr component:
As described above, the highest Cr content point has relatively high strength and improves crack resistance, but on the other hand, it has relatively small hardness and poor wear resistance, and also has poor heat resistance. Therefore, in order to make up for the lack of wear resistance and heat resistance of the highest Cr content point, the Cr content ratio is made relatively small, thereby improving the wear resistance and heat resistance of the entire layer. They are alternately and periodically formed in the thickness direction.
Therefore, Crmin indicating the Cr content at the lowest Cr content point is 0.50a (where the value of a is the composition formula of the (Al, Cr, Si, Ni, Zr) N layer: (Al _{1-a- bcd} Cr _a Si _b Ni _c Zr _d ) If the average composition of Cr is smaller than N), the crack resistance of the entire layer is reduced even if the highest Cr content point having high strength exists adjacently On the other hand, the Crmin indicating the content ratio of Cr at the Cr minimum content point is not a numerical value of a or more according to the definition, so the value of Crmin indicating the Cr concentration at the Cr minimum content point is 0.50a or more and less than a. The value of Crmin desirably satisfies 0.65a ≦ Crmin ≦ 0.95a.

Ｃｒ成分の組成変調におけるＣｒ最高含有点とＣｒ最低含有点の間隔：
Ｃｒ最高含有点とＣｒ最低含有点の間隔が５ｎｍ未満では、それぞれの点を明確に区別して形成することが困難であり、その結果、層に所望の高強度、高温硬さと耐熱性を確保することができなくなり、また、その間隔が１００ｎｍを越えるとそれぞれの点がもつ欠点、すなわちＣｒ最低含有点であれば強度不足、Ｃｒ最高含有点であれば高温硬さと耐熱性不足が層内に局部的に現れ、これが原因で切刃にクラックが発生し易くなり、また、摩耗進行が促進されるようになることから、Ｃｒ最高含有点とＣｒ最低含有点の間隔は５ｎｍ以上１００ｎｍ以下と定めた。 Interval between the highest Cr content point and the lowest Cr content point in the compositional modulation of the Cr component:
If the distance between the highest Cr content point and the lowest Cr content point is less than 5 nm, it is difficult to clearly distinguish each point and form the desired high strength, high temperature hardness and heat resistance for the layer. In addition, when the distance exceeds 100 nm, the defects of the respective points, that is, if the Cr minimum content point is insufficient in strength, if the Cr maximum content point is high temperature hardness and insufficient heat resistance are localized in the layer. As a result, cracks are likely to occur in the cutting edge and the progress of wear is promoted. Therefore, the interval between the highest Cr content point and the lowest Cr content point is determined to be 5 nm or more and 100 nm or less. .

Ｎｉ成分の組成変調構造：
前述のとおり、Ｎｉ成分は、Ｃｒ成分と同じ位相の組成変調を示し、Ｎｉ最高含有点とＮｉ最低含有点の間隔は５ｎｍ以上１００ｎｍ以下であるが、Ｎｉ成分の組成変調とＣｒ成分の組成変調は、位相、周期が同じであるということに加えて、さらに、Ｎｉ成分濃度とＣｒ成分濃度の間に、所定の関係が維持される。
即ち、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の層厚方向の任意の点ｚにおけるＮｉの組成をｃ_ｚ、Ｃｒの組成をａ_ｚとし、また、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層のＮｉの平均組成をｃ、Ｃｒの平均組成をａとした時、ａ_ｚに対するｃ_ｚの比の値（ｃ_ｚ／ａ_ｚ）を、ａに対するｃの比の値（ｃ／ａ）で除した値（ｃ_ｚ／ａ_ｚ）／（ｃ／ａ）は、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の層厚方向全体にわたって０．７≦（ｃ_ｚ／ａ_ｚ）／（ｃ／ａ）≦１．３の関係が維持される。
図２（ａ）には、本発明の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の層厚方向の各位置と、該位置について求めた（ｃ_ｚ／ａ_ｚ）／（ｃ／ａ）の値の関係を示す。
図２（ａ）からも、（ｃ_ｚ／ａ_ｚ）／（ｃ／ａ）の値は、層厚方向全体にわたって、０．７≦（ｃ_ｚ／ａ_ｚ）／（ｃ／ａ）≦１．３の関係が満足されていることがわかる。 Compositional modulation structure of Ni component:
As described above, the Ni component exhibits the same phase composition modulation as the Cr component, and the interval between the Ni highest content point and the Ni lowest content point is 5 nm or more and 100 nm or less, but the Ni component composition modulation and the Cr component composition modulation. In addition to having the same phase and period, a predetermined relationship is maintained between the Ni component concentration and the Cr component concentration.
That is, the composition of Ni at an arbitrary point z in the layer thickness direction of the (Al, Cr, Si, Ni, Zr) N layer is c _z , the composition of Cr is a _z, and (Al, Cr, Si, Ni , Zr) when the average composition of Ni in N layer c, and average composition of Cr was a, the ratio of the values of _{c z} for _{a z} a _(c _z / _a z), the ratio of the values of c for a (c The value (c _z / a _z ) / (c / a) divided by / a) is 0.7 ≦ (c _z / a) over the entire layer thickness direction of the (Al, Cr, Si, Ni, Zr) N layer. _z ) / (c / a) ≦ 1.3 is maintained.
FIG. 2A shows each position in the layer thickness direction of the (Al, Cr, Si, Ni, Zr) N layer of the present invention, and (c _z / a _z ) / (c / a) obtained for the position. ) Value relationship.
Also from FIG. 2A, the value of (c _z / a _z ) / (c / a) is 0.7 ≦ (c _z / a _z ) / (c / a) ≦ 1 over the entire layer thickness direction. It can be seen that the relationship .3 is satisfied.

Ｚｒ成分の組成変調構造：
（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層にＺｒ成分を含有させた場合、Ｚｒ成分は、Ｎｉ成分、Ｃｒ成分と同じ位相の組成変調を示し、Ｚｒ最高含有点とＺｒ最低含有点の間隔は５ｎｍ以上１００ｎｍ以下である。
また、Ｎｉ成分の場合と同様に、Ｚｒ成分濃度とＣｒ成分濃度の間に、次の関係が維持されることが望ましい。
即ち、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の層厚方向の任意の点ｚにおけるＺｒの組成をｄ_ｚ、Ｃｒの組成をａ_ｚとし、また、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層のＺｒの平均組成をｄ、Ｃｒの平均組成をａとした時、ａ_ｚに対するｄ_ｚの比の値（ｄ_ｚ／ａ_ｚ）を、ａに対するｄの比の値（ｄ／ａ）で除した値（ｄ_ｚ／ａ_ｚ）／（ｄ／ａ）は、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の層厚方向全体にわたって０．７≦（ｄ_ｚ／ａ_ｚ）／（ｄ／ａ）≦１．３の関係が維持されることが望ましい。
図２（ｂ）には、本発明の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の層厚方向の各位置と、該位置について求めた（ｄ_ｚ／ａ_ｚ）／（ｄ／ａ）の値の関係を示す。
図２（ｂ）からも、（ｄ_ｚ／ａ_ｚ）／（ｄ／ａ）の値は、層厚方向全体にわたって、０．７≦（ｄ_ｚ／ａ_ｚ）／（ｄ／ａ）≦１．３の関係が満足されていることがわかる。 Composition modulation structure of Zr component:
(Al, Cr, Si, Ni, Zr) When the Zr component is contained in the N layer, the Zr component exhibits compositional modulation having the same phase as the Ni component and the Cr component, and the Zr highest content point and the Zr lowest content point The interval is 5 nm or more and 100 nm or less.
Further, as in the case of the Ni component, it is desirable to maintain the following relationship between the Zr component concentration and the Cr component concentration.
That is, the composition of Zr at an arbitrary point z in the layer thickness direction of the (Al, Cr, Si, Ni, Zr) N layer is d _z , the composition of Cr is a _z, and (Al, Cr, Si, Ni , Zr) when the average composition of Zr N layer was d, the average composition of Cr and a, the ratio of the value of _{d z} for _{a z} a _(d _z / _a z), the ratio of the value of d for a (d The value (d _z / a _z ) / (d / a) divided by / a) is 0.7 ≦ (d _z / a) over the entire layer thickness direction of the (Al, Cr, Si, Ni, Zr) N layer. It is desirable to maintain the relationship of _z ) / (d / a) ≦ 1.3.
FIG. 2B shows each position in the layer thickness direction of the (Al, Cr, Si, Ni, Zr) N layer of the present invention and (d _z / a _z ) / (d / a) obtained for the position. ) Value relationship.
Also from FIG. 2B, the value of (d _z / a _z ) / (d / a) is 0.7 ≦ (d _z / a _z ) / (d / a) ≦ 1 over the entire layer thickness direction. It can be seen that the relationship .3 is satisfied.

本発明の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層は、イオン半径の近いＣｒとＮｉ（およびＺｒ）の比率を所定の範囲内に保つことで、ナノメーターオーダーの組成変調構造を形成し、立方晶の結晶構造を保持しつつも、格子歪を顕著に変調することができる。
したがって、本発明の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層においては、特に、格子歪の変調とＮｉ成分による切削負荷応力緩和効果によって、高速断続切削時に発生したクラックが硬質被覆層の層厚方向に伝播・進展するのではなく、面内方向（工具基体表面とほぼ平行な方向）に誘導されることによって、クラックの伝播・進展を原因とするチッピング、欠損の発生を抑制することができる。 The (Al, Cr, Si, Ni, Zr) N layer of the present invention forms a composition modulation structure on the order of nanometers by keeping the ratio of Cr and Ni (and Zr) having a close ionic radius within a predetermined range. In addition, the lattice strain can be significantly modulated while maintaining the cubic crystal structure.
Therefore, in the (Al, Cr, Si, Ni, Zr) N layer of the present invention, cracks generated during high-speed interrupted cutting are caused in the hard coating layer by the lattice strain modulation and the cutting load stress relaxation effect due to the Ni component. Rather than propagating / developing in the layer thickness direction, it is induced in the in-plane direction (direction almost parallel to the tool base surface) to suppress chipping and chipping caused by crack propagation / development. Can do.

本発明の組成変調構造を有する（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層は、例えば、図３に示すアークイオンプレーティング(以下、「ＡＩＰ」と記す)装置を用いて成膜するに当たり、工具基体をＡＩＰ装置に装入し、回転テーブル上で自転しながら回転する工具基体とＣｒとＮｉとＺｒの最高含有点（言い換えれば、ＡｌとＳｉの最低含有点）形成用ターゲットとの間にアーク放電を発生させて成膜すると同時に、回転テーブル上で自転しながら回転する工具基体とＣｒとＮｉとＺｒの最低含有点（言い換えれば、ＡｌとＳｉの最高含有点）形成用ターゲットとの間にもアーク放電を発生させて成膜することによって、組成変調構造を有する（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層を形成することができる。 The (Al, Cr, Si, Ni, Zr) N layer having the composition modulation structure of the present invention is formed by using, for example, an arc ion plating (hereinafter referred to as “AIP”) apparatus shown in FIG. The tool base is inserted into the AIP apparatus, and rotates between the tool base and the target for forming the highest content point of Cr, Ni and Zr (in other words, the lowest content point of Al and Si) while rotating on the rotary table. In addition to forming a film by generating arc discharge at the same time, a tool base that rotates while rotating on a rotary table and a target for forming the lowest content point of Cr, Ni, and Zr (in other words, the highest content point of Al and Si) are formed. An (Al, Cr, Si, Ni, Zr) N layer having a composition modulation structure can be formed by forming a film by generating arc discharge in the meantime.

本発明の被覆工具は、硬質被覆層が、少なくとも、立方晶結晶構造を主体とする所定の平均組成の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層からなる層を含み、また、該（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層において層を構成する各成分の組成が層厚方向に沿って周期的に変化し、特に、層厚方向の任意の測定点ｚにおけるＮｉの組成をｃ_ｚ、Ｃｒの組成をａ_ｚとし、また、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層のＮｉの平均組成をｃ、Ｃｒの平均組成をａとした時、ａ_ｚに対するｃ_ｚの比の値（ｃ_ｚ／ａ_ｚ）を、ａに対するｃの比の値（ｃ／ａ）で除した値（ｃ_ｚ／ａ_ｚ）／（ｃ／ａ）は、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の層厚方向全体にわたって０．７≦（ｃ_ｚ／ａ_ｚ）／（ｃ／ａ）≦１．３の関係が満足されることから、耐クラック性と耐摩耗性の双方が同時に向上する。
また、好ましくは、層厚方向の任意の測定点ｚにおけるＺｒの組成をｄ_ｚ、Ｃｒの組成をａ_ｚとし、また、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層のＺｒの平均組成をｄ、Ｃｒの平均組成をａとした時、ａ_ｚに対するｄ_ｚの比の値（ｄ_ｚ／ａ_ｚ）を、ａに対するｄの比の値（ｄ／ａ）で除した値（ｄ_ｚ／ａ_ｚ）／（ｄ／ａ）は、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の層厚方向全体にわたって０．７≦（ｄ_ｚ／ａ_ｚ）／（ｄ／ａ）≦１．３の関係が満足される場合に、より一層、すぐれた耐クラック性と耐摩耗性の双方が同時に発揮される。 In the coated tool of the present invention, the hard coating layer includes at least a layer composed of an (Al, Cr, Si, Ni, Zr) N layer having a predetermined average composition mainly composed of a cubic crystal structure, The composition of each component constituting the layer in the Al, Cr, Si, Ni, Zr) N layer periodically changes along the layer thickness direction, and in particular, the composition of Ni at an arbitrary measurement point z in the layer thickness direction. When the composition of c _z and Cr is a _z , the average composition of Ni in the (Al, Cr, Si, Ni, Zr) N layer is c, and the average composition of Cr is a, the ratio of c _{z to} a _z the ratio of the values _(c _z / _a z), the value obtained by dividing the ratio of the values of c for _{a (c / a) (c} z / a z) / (c / a) is, (Al, Cr, Si, Ni, Zr) relationship 0.7 ≦ throughout the layer thickness direction of the N layer _{_{(c z / a z) /}} (c / a) ≦ 1.3 is satisfied From both crack resistance and wear resistance is improved at the same time.
Preferably, the composition of Zr at an arbitrary measurement point z in the layer thickness direction is d _z , the composition of Cr is a _z, and the average composition of Zr of the (Al, Cr, Si, Ni, Zr) N layer the d, when the average composition of Cr was a, the value of the ratio of _{d z} for _{a z} a _(d _z / _a z), divided by the ratio of the values of d for a (d / a) value _{(d z} / A _z ) / (d / a) is 0.7 ≦ (d _z / a _z ) / (d / a) ≦ 1 over the entire thickness direction of the (Al, Cr, Si, Ni, Zr) N layer. When the relationship of .3 is satisfied, both excellent crack resistance and wear resistance are exhibited at the same time.

したがって、本発明の被覆工具は、高熱発生を伴い、かつ、切刃に対して大きな衝撃的・機械的負荷がかかる焼き入れ鋼の高速ミーリング加工等の高速断続切削加工においても、すぐれた耐クラック性と耐摩耗性を長期に亘って発揮するものである。 Therefore, the coated tool of the present invention has excellent crack resistance even in high-speed intermittent cutting processing such as high-speed milling processing of hardened steel that is accompanied by high heat generation and a large impact and mechanical load on the cutting edge. And exhibits wear resistance over a long period of time.

本発明被覆工具の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層における組成変調の様子を示し、（ａ）は、Ｃｒ成分とＮｉ成分とＺｒ成分の組成変調の様子を、（ｂ）は、Ａｌ成分とＳｉ成分の組成変調の様子を示す。The mode of composition modulation in the (Al, Cr, Si, Ni, Zr) N layer of the coated tool of the present invention is shown, (a) shows the mode of composition modulation of Cr component, Ni component and Zr component, (b) The state of composition modulation of the Al component and the Si component is shown. （ａ）は、本発明の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の層厚方向の各位置と、該位置について求めた（ｃ_ｚ／ａ_ｚ）／（ｃ／ａ）の値の関係の一例を示し、（ｂ）は、本発明の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の層厚方向の各位置と、該位置について求めた（ｄ_ｚ／ａ_ｚ）／（ｄ／ａ）の値の関係の一例を示す。(A) is each position of the (Al, Cr, Si, Ni, Zr) N layer of the present invention in the layer thickness direction, and the value of (c _z / a _z ) / (c / a) obtained for the position. (B) shows each position in the layer thickness direction of the (Al, Cr, Si, Ni, Zr) N layer of the present invention, and (d _z / a _z ) / An example of the relationship of the value of (d / a) is shown. 本発明被覆工具の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層を形成するのに用いたアークイオンプレーティング（ＡＩＰ）装置を示し、（ａ）は概略平面図、（ｂ）は概略正面図である。The arc ion plating (AIP) apparatus used to form the (Al, Cr, Si, Ni, Zr) N layer of the coated tool of the present invention is shown, (a) is a schematic plan view, and (b) is a schematic front view. FIG.

つぎに、この発明の被覆工具を実施例により具体的に説明する。
なお、以下の実施例では、炭化タングステン基超硬合金を工具基体とする被覆工具について説明するが、工具基体として、炭窒化チタン基サーメットあるいは立方晶窒化硼素焼結体を用いた場合も同様である。 Next, the coated tool of the present invention will be specifically described with reference to examples.
In the following examples, a coated tool using a tungsten carbide base cemented carbide as a tool base will be described. However, the same applies when a titanium carbonitride based cermet or a cubic boron nitride sintered body is used as the tool base. is there.

原料粉末として、平均粒径：５．５μｍを有する中粗粒ＷＣ粉末、同０．８μｍの微粒ＷＣ粉末、同１．３μｍのＴａＣ粉末、同１．２μｍのＮｂＣ粉末、同１．２μｍのＺｒＣ粉末、同２．３μｍのＣｒ_３Ｃ_２粉末、同１．５μｍのＶＣ粉末、同１．０μｍの（Ｔｉ，Ｗ）Ｃ［質量比で、ＴｉＣ／ＷＣ＝５０／５０］粉末、および同１．８μｍのＣｏ粉末を用意し、これら原料粉末をそれぞれ表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、１００ＭＰａの圧力で所定形状の各種の圧粉体に押出しプレス成形し、これらの圧粉体を、６Ｐａの真空雰囲気中、７℃／分の昇温速度で１３７０〜１４７０℃の範囲内の所定の温度に昇温し、この温度に１時間保持後、炉冷の条件で焼結して、直径が１０ｍｍの工具基体形成用丸棒焼結体を形成し、さらに前記丸棒焼結体から、研削加工にて、切刃部の直径×長さが６ｍｍ×１２ｍｍの寸法で、ねじれ角３０度の２枚刃ボール形状をもったＷＣ基超硬合金製の工具基体（エンドミル）１〜３をそれぞれ製造した。 As raw material powders, medium coarse WC powder having an average particle diameter of 5.5 μm, fine WC powder of 0.8 μm, TaC powder of 1.3 μm, NbC powder of 1.2 μm, ZrC of 1.2 μm Powder, 2.3 μm Cr ₃ C ₂ powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C [by mass ratio, TiC / WC = 50/50] powder, and 1 .8 μm Co powder was prepared, each of these raw material powders was blended in the blending composition shown in Table 1, added with wax, ball milled in acetone for 24 hours, dried under reduced pressure, and then pressed into a predetermined shape at a pressure of 100 MPa. Extruded and pressed into various types of green compacts, and these green compacts were heated to a predetermined temperature in the range of 1370 to 1470 ° C. at a temperature increase rate of 7 ° C./min in a 6 Pa vacuum atmosphere. Conditions for furnace cooling after holding at this temperature for 1 hour Sintered to form a round tool sintered body for forming a tool base having a diameter of 10 mm, and further, from the round bar sintered body, a diameter x length of a cutting edge portion is 6 mm x 12 mm by grinding. Thus, tool bases (end mills) 1 to 3 made of a WC-base cemented carbide having a two-blade ball shape with a twist angle of 30 degrees were manufactured.

（ａ）上記の工具基体１〜３のそれぞれを、アセトン中で超音波洗浄し、乾燥した状態で、図３に示すＡＩＰ装置の回転テーブル上の中心軸から半径方向に所定距離離れた位置に外周部にそって装着し、ＡＩＰ装置内にボンバード洗浄用のＴｉカソード電極(図示せず)、所定組成のＣｒとＮｉとＺｒの最高含有点形成用Ａｌ−Ｃｒ−Ｓｉ−Ｎｉ−Ｚｒ合金ターゲット（カソード電極）および所定組成のＣｒとＮｉとＺｒの最低含有点形成用Ａｌ−Ｃｒ−Ｓｉ−Ｎｉ−Ｚｒ合金ターゲット（カソード電極）を装置内に相対向して配置し、
（ｂ）まず、装置内を排気して真空に保持しながら、ヒータで工具基体を４００℃に加熱した後、前記回転テーブル上で自転しながら回転する工具基体に−１０００Ｖの直流バイアス電圧を印加し、かつ、Ｔｉカソード電極とアノード電極との間に１００Ａの電流を流してアーク放電を発生させ、もって工具基体表面をボンバード洗浄し、
（ｃ）ついで、装置内に反応ガスとして窒素ガスを導入して表２に示す窒素圧とすると共に、前記回転テーブル上で自転しながら回転する工具基体の温度を表２に示す温度範囲内に維持するとともに表２に示す直流バイアス電圧を印加し、かつ前記ＣｒとＮｉとＺｒの最高含有点形成用Ａｌ−Ｃｒ−Ｓｉ−Ｎｉ−Ｚｒ合金ターゲット（カソード電極）とアノード電極、さらに、ＣｒとＮｉとＺｒの最低含有点形成用Ａｌ−Ｃｒ−Ｓｉ−Ｎｉ−Ｚｒ合金ターゲット（カソード電極）とアノード電極との間に、それぞれ１００Ａの電流を流してアーク放電を同時に発生させ、もって前記工具基体の表面に、表４に示される所定の組成、目標平均層厚、組成変調の周期、Ｃｒｍａｘ、Ｎｉｍａｘ、Ｚｒｍａｘ、Ｃｒｍｉｎ、Ｎｉｍｉｎ、Ｚｒｍｉｎからなる各成分濃度の変化を有する（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層からなる硬質被覆層を蒸着形成することにより、
表４に示す本発明被覆工具としての表面被覆エンドミル１〜１０（以下、本発明１〜１０という）をそれぞれ製造した。 (A) Each of the tool bases 1 to 3 is ultrasonically cleaned in acetone and dried, at a position spaced apart from the central axis on the rotary table of the AIP apparatus shown in FIG. 3 by a predetermined distance in the radial direction. Attached along the outer periphery, Ti cathode electrode for bombard cleaning (not shown) in the AIP apparatus, Al-Cr-Si-Ni-Zr alloy target for forming the highest content point of Cr, Ni and Zr with a predetermined composition (Cathode electrode) and an Al—Cr—Si—Ni—Zr alloy target (cathode electrode) for forming the lowest content point of Cr, Ni and Zr having a predetermined composition are arranged opposite to each other in the apparatus,
(B) First, the tool base is heated to 400 ° C. with a heater while the inside of the apparatus is evacuated and kept in vacuum, and then a DC bias voltage of −1000 V is applied to the tool base that rotates while rotating on the rotary table. And an arc discharge is caused by flowing a current of 100 A between the Ti cathode electrode and the anode electrode, thereby bombarding the surface of the tool substrate,
(C) Next, nitrogen gas is introduced as a reactive gas into the apparatus to obtain the nitrogen pressure shown in Table 2, and the temperature of the tool base rotating while rotating on the rotary table is within the temperature range shown in Table 2. And applying the DC bias voltage shown in Table 2, and forming the highest content point of Cr, Ni, and Zr, the Al—Cr—Si—Ni—Zr alloy target (cathode electrode), the anode electrode, and Cr A current of 100 A is passed between the Al-Cr-Si-Ni-Zr alloy target (cathode electrode) for forming the minimum content point of Ni and Zr and the anode electrode to simultaneously generate an arc discharge, whereby the tool base On the surface, the predetermined composition shown in Table 4, target average layer thickness, composition modulation period, Crmax, Nimax, Zrmax, Crmin, Nimin, Zrmin Ranaru with the change in concentration of each component (Al, Cr, Si, Ni, Zr) by depositing form a hard coating layer consisting of N layers,
Surface coated end mills 1 to 10 (hereinafter referred to as the present invention 1 to 10) as the present invention coated tools shown in Table 4 were produced.

［比較例］
比較の目的で、上記実施例における（ｃ）の工程を、表３に示す条件（即ち、窒素圧、工具基体の温度、直流バイアス電圧）で行い、その他は実施例と同一の条件で成膜することにより、表５に示す比較例被覆工具としての表面被覆エンドミル１〜１０（以下、比較例１〜１０という）をそれぞれ製造した。
すなわち、比較例１〜１０の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層は、いずれも、本発明で規定する要件を備えていないものである。
さらに、参考のため、一種類の組成を有するＡｌ−Ｃｒ−Ｓｉ−Ｎｉ−Ｚｒ合金ターゲット（カソード電極）を用いて、表３に示す条件（即ち、窒素圧、工具基体の温度、直流バイアス電圧）で（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層を成膜することにより、表５に示す参考例被覆工具としての表面被覆エンドミル１〜３（以下、参考例１〜３という）を製造した。 [Comparative example]
For the purpose of comparison, the step (c) in the above example was performed under the conditions shown in Table 3 (that is, the nitrogen pressure, the temperature of the tool base, and the DC bias voltage), and the other conditions were the same as in the example. Thus, surface-coated end mills 1 to 10 (hereinafter referred to as Comparative Examples 1 to 10) as comparative example-coated tools shown in Table 5 were produced.
That is, none of the (Al, Cr, Si, Ni, Zr) N layers of Comparative Examples 1 to 10 has the requirements defined in the present invention.
Further, for reference, using an Al—Cr—Si—Ni—Zr alloy target (cathode electrode) having one kind of composition, the conditions shown in Table 3 (ie, nitrogen pressure, tool substrate temperature, DC bias voltage) ) To produce surface-coated end mills 1 to 3 (hereinafter referred to as Reference Examples 1 to 3) as reference example-coated tools shown in Table 5 by forming (Al, Cr, Si, Ni, Zr) N layers. did.

上記で作製した本発明１〜１０、比較例１〜１０および参考例１〜３の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の組成を、その層厚方向に沿って、走査型電子顕微鏡（ＳＥＭ）を用いたエネルギー分散型Ｘ線分析法（ＥＤＳ）により測定し、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層全体の平均組成を求めた。
また、その層厚を、走査型電子顕微鏡を用いて断面測定し、５ヶ所の測定値の平均値から、平均層厚を算出した。 The composition of the (Al, Cr, Si, Ni, Zr) N layers of the present invention 1 to 10, the comparative examples 1 to 10 and the reference examples 1 to 3 manufactured as described above is scanned along the layer thickness direction. The average composition of the entire (Al, Cr, Si, Ni, Zr) N layer was determined by energy dispersive X-ray analysis (EDS) using a microscope (SEM).
Further, the layer thickness was measured by a cross-section using a scanning electron microscope, and the average layer thickness was calculated from the average value of the five measured values.

さらに、本発明１〜１０および比較例１〜１０の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層について、走査型電子顕微鏡（ＳＥＭ）、透過型電子顕微鏡（ＴＥＭ）およびエネルギー分散型Ｘ線分析法（ＥＤＳ）を用いた層厚方向に沿った測定により、ＣｒとＮｉとＺｒの最高含有点におけるＣｒ濃度Ｃｒｍａｘの値、Ｎｉ濃度Ｎｉ最高含有点とＮｉ最低含有点の値、Ｚｒ濃度Ｚｒｍａｘの値、ＣｒとＮｉとＺｒの最低含有点におけるＣｒ濃度Ｃｒｍｉｎの値、Ｎｉ濃度Ｎｉｍｉｎの値、Ｚｒ濃度Ｚｒｍｉｎの値、Ｃｒ最高含有点とＣｒ最低含有点の間隔、Ｎｉ最高含有点とＮｉ最低含有点の間隔、Ｚｒ最高含有点とＺｒ最低含有点の間隔を測定した。
前記の平均組成、Ｃｒｍａｘの値、Ｎｉｍａｘの値、Ｚｒｍａｘの値、Ｃｒｍｉｎの値、Ｎｉｍｉｎの値、Ｚｒｍｉｎの値、Ｃｒ最高含有点とＣｒ最低含有点の間隔、Ｎｉ最高含有点とＮｉ最低含有点の間隔、Ｚｒ最高含有点とＺｒ最低含有点の間隔は、いずれも複数個所の測定値の平均値として求めたものである。
なお、Ｎｉ最高含有点とＮｉ最低含有点の間隔、Ｚｒ最高含有点とＺｒ最低含有点の間隔は、実質的に、Ｃｒ最高含有点とＣｒ最低含有点の間隔と同一であった。 Further, for the (Al, Cr, Si, Ni, Zr) N layers of the present invention 1-10 and Comparative Examples 1-10, a scanning electron microscope (SEM), a transmission electron microscope (TEM), and an energy dispersive X-ray By the measurement along the layer thickness direction using the analysis method (EDS), the Cr concentration Crmax value at the highest content point of Cr, Ni and Zr, the Ni concentration Ni highest content point and the Ni lowest content point value, Zr concentration Zrmax Value, Cr concentration Crmin value at the minimum content point of Cr, Ni and Zr, Ni concentration Nimin value, Zr concentration Zrmin value, interval between Cr highest content point and Cr lowest content point, Ni highest content point and Ni lowest value The interval between the content points and the distance between the highest Zr content point and the lowest Zr content point were measured.
The above average composition, Crmax value, Nimax value, Zrmax value, Crmin value, Nimin value, Zrmin value, the interval between the highest Cr content point and the lowest Cr content point, the highest Ni content point and the lowest Ni content point , And the interval between the highest Zr content point and the lowest Zr content point are determined as average values of measured values at a plurality of locations.
The distance between the highest Ni content point and the lowest Ni content point, and the distance between the highest Zr content point and the lowest Zr content point were substantially the same as the distance between the highest Cr content point and the lowest Cr content point.

また、本発明１〜１０および比較例１〜１０の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層について、層厚方向に沿った任意の１０箇所の測定点ｚｎ（ｎ＝１，２，３，・・１０）において、Ｃｒの濃度ａ_ｚｎ、Ｃｕの濃度ｃ_ｚｎ、Ｚｒの濃度ｄ_ｚｎを測定して（ｃ_ｚｎ／ａ_ｚｎ）／（ｃ／ａ）、（ｄ_ｚｎ／ａ_ｚｎ）／（ｄ／ａ）を算出し、これらの値の最大値と最小値を求めた。
さらに、本発明１〜１０、比較例１〜１０および参考例１〜３の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層について、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層のＸ線回折を行い、いずれの場合においても、立方晶構造または六方晶構造を有する結晶が存在することを確認した。
なお、Ｘ線回折は、測定条件:Ｃｕ管球、測定範囲（２θ）：３０〜８０度、スキャンステップ：０．０１３度、１ステップ辺り測定時間：０．４８ｓｅｃ／ｓｔｅｐという条件で測定した。
表４、表５に、測定・算出したそれぞれの値を示す。 For the (Al, Cr, Si, Ni, Zr) N layers of the present invention 1 to 10 and comparative examples 1 to 10, arbitrary 10 measurement points zn (n = 1, 2, 3... 10), the Cr concentration a _zn , the Cu concentration c _zn , and the Zr concentration d _zn are measured to obtain (c _zn / a _zn ) / (c / a), (d _zn / a _zn ). / (D / a) was calculated, and the maximum and minimum values of these values were obtained.
Further, for the (Al, Cr, Si, Ni, Zr) N layer of the present invention 1-10, Comparative Examples 1-10 and Reference Examples 1-3, the (Al, Cr, Si, Ni, Zr) N layer X Line diffraction was performed, and in each case, it was confirmed that crystals having a cubic structure or a hexagonal structure existed.
X-ray diffraction was measured under the conditions of measurement conditions: Cu tube, measurement range (2θ): 30 to 80 degrees, scan step: 0.013 degrees, measurement time per step: 0.48 sec / step.
Tables 4 and 5 show the measured and calculated values.

つぎに、上記本発明１〜１０、比較例１〜１０および参考例１〜３のエンドミルについて、下記の切削条件Ａ、Ｂによる焼き入れ鋼の側面切削加工試験を実施した。
≪切削条件Ａ≫
被削材−平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＫＤ１１（６０ＨＲＣ）の板材、
切削速度：１０７ｍ／ｍｉｎ、
回転速度：６０００ｍｉｎ．^−１、
切り込み：ae ０．２５ｍｍ、ap ２．０ｍｍ、
送り速度（１刃当り）：０．０４ｍｍ／ｔｏｏｔｈ、
切削長：３２ｍ、
≪切削条件Ｂ≫
被削材−平面寸法：１００ｍｍ×２５０ｍｍ、厚さ：５０ｍｍのＪＩＳ・ＳＫＤ５１（６４ＨＲＣ）の板材、
切削速度：１０７ｍ／ｍｉｎ、
回転速度：６０００ｍｉｎ．^−１、
切り込み：ae ０．２５ｍｍ、ap ０．０６ｍｍ、
送り速度（１刃当り）：０．０４ｍｍ／ｔｏｏｔｈ、
切削長：１８ｍ、
いずれの側面切削加工試験でも切刃の逃げ面摩耗幅を測定した。
この測定結果を表６に示した。 Next, the side milling test of the hardened steel by the following cutting conditions A and B was implemented about the end mills of the present inventions 1 to 10, Comparative Examples 1 to 10, and Reference Examples 1 to 3.
≪Cutting condition A≫
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SKD11 (60HRC) plate material,
Cutting speed: 107 m / min,
Rotational speed: 6000 min. ^-1 ,
Incision: ae 0.25mm, ap 2.0mm,
Feed rate (per tooth): 0.04 mm / tooth,
Cutting length: 32 m
≪Cutting condition B≫
Work material-Plane dimension: 100 mm x 250 mm, thickness: 50 mm JIS / SKD51 (64HRC) plate material,
Cutting speed: 107 m / min,
Rotational speed: 6000 min. ^-1 ,
Incision: ae 0.25mm, ap 0.06mm,
Feed rate (per tooth): 0.04 mm / tooth,
Cutting length: 18 m
In any side cutting test, the flank wear width of the cutting edge was measured.
The measurement results are shown in Table 6.

表６に示される結果から、本発明の被覆工具は、硬質被覆層として、少なくとも所定の平均組成の（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層を含み、かつ、該層中には、Ｃｒ成分、Ｎｉ成分及びＺｒ成分の組成変調構造が形成されていることによって、（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層は、耐クラック性と耐摩耗性の両特性を兼ね備えるため、焼き入れ鋼等の高速断続切削加工において、長期の使用にわたってすぐれた切削性能を発揮するものである。
これに対して、硬質被覆層を構成する（Ａｌ，Ｃｒ，Ｓｉ，Ｎｉ，Ｚｒ）Ｎ層の平均組成、あるいはＣｒ成分、Ｎｉ成分及びＺｒ成分の組成変調構造が本発明の規定を外れる比較例の被覆工具、参考例の被覆工具では、クラックの発生・伝播、あるいは、摩耗進行によって、比較的短時間で使用寿命に至ることが明らかである。 From the results shown in Table 6, the coated tool of the present invention includes at least a (Al, Cr, Si, Ni, Zr) N layer having a predetermined average composition as the hard coating layer, and in the layer, Since the composition modulation structure of the Cr component, Ni component and Zr component is formed, the (Al, Cr, Si, Ni, Zr) N layer has both crack resistance and wear resistance characteristics. In high-speed intermittent cutting such as cast steel, it exhibits excellent cutting performance over a long period of use.
On the other hand, the average composition of the (Al, Cr, Si, Ni, Zr) N layer constituting the hard coating layer, or the comparative example in which the composition modulation structure of the Cr component, Ni component and Zr component deviates from the definition of the present invention. It is apparent that the coated tool of No. 1 and the coated tool of the reference example reach the service life in a relatively short time due to generation / propagation of cracks or progress of wear.

この発明の被覆工具は、焼き入れ鋼等の高速断続切削加工に供した場合に、すぐれた耐クラック性とともに長期の使用に亘ってすぐれた耐摩耗性を発揮するものであるから、切削加工装置のＦＡ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。
The coated tool of this invention exhibits excellent wear resistance over a long period of use as well as excellent crack resistance when subjected to high-speed intermittent cutting processing such as hardened steel. It is possible to sufficiently satisfactorily cope with the shift to FA, labor saving and energy saving of cutting, and cost reduction.

Claims

In a surface-coated cutting tool in which a hard coating layer is provided on the surface of a tool substrate made of any of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, or cubic boron nitride sintered body,
(A) The hard coating layer includes at least a composite nitride layer of Al, Cr, Si, Ni, and Zr having a cubic structure with an average layer thickness of 0.5 to 8.0 μm,
(B) The composite nitride layer is
_Formula: when expressed in _{(Al 1-a-b-} c-d Cr a Si b Ni c Zr d) N,
0.15 ≦ a ≦ 0.40, 0.05 ≦ b ≦ 0.20, 0.002 ≦ c ≦ 0.02, 0 ≦ d ≦ 0.02 (where a, b, c, and d are all Having an average composition satisfying (atomic ratio),
(C) The composite nitride layer has a composition modulation structure in which the Cr component concentration periodically changes along the layer thickness direction and a composition modulation structure in which the Ni component concentration periodically changes.
(D) The periodic change of the Cr component concentration in the composition modulation structure is repeated at intervals of 5 nm to 100 nm between the highest content point of the Cr component and the lowest content point of the Cr component,
(E) The concentration Crmax of the Cr component at the highest content point of the Cr component is:
a <Crmax ≦ 1.30a.
On the other hand, the concentration Crmin of the Cr component at the minimum content point of the Cr component is
0.50a ≦ Crmin <a (where a represents the average composition a of Cr in the composition formula (b)),
(F) The periodic change of the Ni component concentration in the composition modulation structure is repeated at intervals of 5 nm to 100 nm between the highest content point of the Ni component and the lowest content point of the Ni component,
(G) a composition of Ni at any measuring point z along the thickness direction _c z, when a composition of Cr was _{a z,} the ratio of _{c z} for _{a z} value _(c _z / _a z), The value (c _z / a _z ) / (c / a) obtained by dividing the ratio (c / a) of the average composition c of Ni to the average composition a of Cr in the composite nitride layer over the entire layer thickness direction. A surface-coated cutting tool characterized by being in a range of 0.7 ≦ (c _z / a _z ) / (c / a) ≦ 1.3.

The surface-coated cutting tool according to claim 1, wherein the content ratio d of Zr in the composite nitride layer satisfies 0.002 ≦ d ≦ 0.02.
(A) The composite nitride layer has a composition modulation structure in which the Zr component concentration changes periodically along the layer thickness direction,
(B) The periodic change in the Zr component concentration in the composition modulation structure is repeated at intervals of 5 nm to 100 nm between the highest content point of the Zr component and the lowest content point of the Zr component,
The composition of Zr at any measuring point z along the (c) layer thickness direction _d z, when a composition of Cr was _{a z,} the ratio of _{d z} for _{a z} value _(d _z / _a z), The value (d _z / a _z ) / (d / a) divided by the value (d / a) of the ratio of the average composition d of Zr to the average composition a of Cr in the composite nitride layer is the entire layer thickness direction. It exists in the range of 0.7 <= ( _dz / _az ) / (d / a) <= 1.3, The surface-coated cutting tool of Claim 1 characterized by the above-mentioned.