JP2004176085A

JP2004176085A - Hard film

Info

Publication number: JP2004176085A
Application number: JP2002340796A
Authority: JP
Inventors: Takashi Ishikawa; 剛史石川
Original assignee: Hitachi Tool Engineering Ltd
Current assignee: Moldino Tool Engineering Ltd
Priority date: 2002-11-25
Filing date: 2002-11-25
Publication date: 2004-06-24
Anticipated expiration: 2022-11-25
Also published as: JP3640310B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hard film which is obtained by improving the adhesion, hot oxidation resistance characteristics and wear resistance of an (AlCr)N based film, and which particularly has high hardness. <P>SOLUTION: The hard film formed by an arc-discharge ion- plating method is represented by (Al<SB>x</SB>Cr<SB>1-x-y</SB>Si<SB>y</SB>) (N<SB>1-α-β-γ</SB>B<SB>α</SB>C<SB>β</SB>O<SB>γ</SB>), wherein x, y, α, β and γ are respectively atomic ratios meeting 0.45<x<0.75, 0<y<0.20, 0≤α<0.12, 0≤β<0.20, and 0<γ<0.25, and has binding energy of at least Cr, Al and/or Si with oxygen in the range of 525 to 535 eV in X-ray photoelectron spectroscopic analysis. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明が属する技術分野】
本発明は、切削工具の表面に被覆する硬質皮膜、或いは金型、軸受け、ダイス、ロールなど高硬度が要求される耐摩耗部材の表面に被覆する硬質皮膜、もしくは内燃機関部品等の耐熱部材の表面に被覆する硬質皮膜に関する。
【０００２】
【従来の技術】
ＡｌＣｒ系皮膜は、耐高温酸化特性に優れた硬質皮膜材として、特許第３０２７５０２号公報、特許第３０３９３８１号公報及び特開２００２−１６０１２９号公報に開示されている。特許第３０２７５０２号公報は金属成分としてＡｌＣｒとＣ、Ｎ、Ｏの１種より選択されるＡｌＣｒ系硬質膜において、高硬度を有する非晶質膜に関する事例が開示されている。しかしこの非晶質膜の硬度は最大でもヌープ硬さ２１ＧＰａ程度であり、耐摩耗効果は期待できず、密着性に関しても十分ではない。特許第３０３９３８１号公報及び特開平２００２−１６０１２９号公報に開示されている硬質皮膜はＡｌＣｒの窒化物であり、約１０００℃の耐高温酸化特性を有しているが、１０００℃以上の耐酸化特性の検討は行われていない。硬度はＨＶ２１ＧＰａ程度で硬度の改善が不十分であり耐摩耗性に乏しい。
【０００３】
【発明が解決しようとする課題】
本発明はこうした事情に着目してなされたものであって、耐高温酸化特性に優れ、高硬度を有し、基体との密着性に極めて優れる硬質皮膜を提供することを目的とする。
【０００４】
【課題を解決するために手段】
上記目的を達成し得た本発明に係る硬質皮膜とは、アーク放電式イオンプレーティング法により被覆される硬質皮膜であって、該硬質皮膜は（Ａｌ_ｘＣｒ_{１−ｘ−ｙ}Ｓｉ_ｙ）（Ｎ_{１−α−β−γ}Ｂ_αＣ_βＯ_γ）、但し、ｘ、ｙ、α、β、γは夫々原子比率を示し、０．４５＜Ｘ＜０．７５、０＜ｙ＜０．２０、０≦α＜０．１２、０≦β＜０．２０、０＜γ＜０．２５からなり、Ｘ線光電子分光分析における５２５ｅＶから５３５ｅＶの範囲に少なくともＣｒ、Ａｌ及び／又はＳｉと酸素との結合エネルギーを有することを特徴とする硬質皮膜である。これにより、基体との密着性、耐高温酸化性が改善されることを突き止め、本発明を完成させた。
【０００５】
更に、本発明の硬質皮膜において、該硬質皮膜のＳｉの化学結合状態は、Ｘ線光電子分光分析により、少なくとも窒化物、酸化物及び金属の各状態が存在し、Ｓｉの窒化物の強度比率をＩ（Ｓｉ−Ｎ）、Ｓｉの酸化物の強度比率をＩ（Ｓｉ−Ｏ）、Ｓｉの金属の強度比率をＩ（Ｓｉ）、但し、Ｉ（Ｓｉ−Ｎ）＋Ｉ（Ｓｉ−Ｏ）＋Ｉ（Ｓｉ）＝１００％を示し、Ｉ（Ｓｉ−Ｎ）が５２％以上とすることにより硬質皮膜の高硬度化に有効であり好ましい。該硬質皮膜はナノインデンテーションによる硬度測定法において荷重除去曲線の接触剛性より算出される接触深さと、最大荷重時の最大変化量が求められる（Ｗ．Ｃ．Ｏｌｉｖｅｒａｎｄ、Ｇ．Ｍ．Ｐｈａｒｒ：Ｊ．Ｍａｔｅｒ．Ｒｅｓ．，Ｖｏｌ．７，Ｎｏ．６，Ｊｕｎｅ１９９２１５６４−１５８３）。この数値を用いて、Ｅ＝１００−｛（接触深さ）／（最大荷重時の最大変位量）｝
の数式で、弾性回復率Ｅを定義し、３２％≦Ｅ＜４２％とすることにより、耐摩耗性と密着性のバランスが最適となり好ましい。該硬質皮膜はＸ線回折における最強回折強度が（２００）面又は（１１１）面に有する結晶質からなることを特徴とする硬質皮膜である。
【０００６】
【発明の実施の形態】
本発明者は、基体との密着性、耐高温酸化特性に優れ高硬度を有した硬質皮膜を得ることを目的として研究した結果、硬質皮膜の組成並びに成膜条件であるバイアス電圧、反応ガス圧やその分圧比、成膜時の基体温度の検討によって目的を達成する本発明の硬質皮膜を完成した。本発明の硬質皮膜をアーク放電式イオンプレーティングにより被覆することにより、過酷な摩耗環境下において問題となる耐塑性変形性能である靭性が著しく改善される。これより、例えば金型、工具、耐摩耗部材及び耐熱部材の基体表面に適用した場合も剥離等の問題が生じず、硬質皮膜の耐高温酸化特性並びに耐摩耗性を十分発揮する。
【０００７】
本発明の硬質皮膜を構成する金属元素の組成は、（Ａｌ_ｘＣｒ_{１−ｘ−ｙ}Ｓｉ_ｙ）においてｘが０．４５＜ｘ＜０．７５、ｙが０＜ｙ＜０．２０を満足する必要がある。ｘの値が０．４５以下、ｙの値が０では、皮膜硬度並びに耐高温酸化特性の改善効果が十分ではなく、ｘの値が０．７５以上、ｙの値が０．２０以上では、残留圧縮応力が過大になり、被覆直後に自己破壊を誘発する場合がある。また同時に六方晶が確認される場合もあり、強度が急激に低下する。（Ｎ_{１−α−β−γ}Ｂ_αＣ_βＯ_γ）の非金属元素のαは、０．１２以上で皮膜の脆化が確認された。好ましいαの上限値としては０．０８である。硼素の添加は被加工物との耐溶着性と高温環境下における摩擦係数を低減させる効果があり好ましい。βは、０．２０以上で皮膜の脆化が確認された。好ましいβの上限値は０．１６である。炭素の添加は硬質皮膜の硬度を高め、室温における摩擦係数の低減に効果的である。γは、０を超えて大きく０．２５未満とする必要がある。γが０．２５以上では、皮膜硬度が著しく低下し、耐摩耗性に乏しくなる。好ましいγの値は、０．０２以上０．２０以下である。金属元素のＡｌ、Ｃｒ、Ｓｉに対する非金属元素のＮ、Ｂ、Ｃ、Ｏの比は、化学量論的に（Ｎ、Ｂ、Ｃ、Ｏ）／（Ａｌ、Ｃｒ、Ｓｉ）＞１．１がより好ましい。
【０００８】
Ｘ線光電子分光分析において、５２５ｅＶから５３５ｅＶにＣｒ、Ａｌ及び／又はＳｉと酸素との結合エネルギーを有することが必要である。高温酸化雰囲気においては酸素の拡散経路となる結晶粒界を不明瞭とすることにより、酸素の内向拡散を著しく抑制することが可能となった。高温酸化環境下において、硬質皮膜の最表面に極めて緻密なＳｉを含有したＡｌとＣｒの酸化保護層を形成することも酸化抑制に大きく貢献している。これは極最表面で形成される酸化物が、例えばＡｌＴｉ系硬質皮膜又はＡｌＣｒ系硬質皮膜で形成されるＴｉＯ_２、Ａｌ_２Ｏ_３、Ｃｒ_２Ｏ_３よりも、層分離が起こり難いためである。皮膜の硬度に関しては、Ｃｒ、Ａｌ及び／又はＳｉが窒化物、酸化物又は酸窒化物の状態で存在し、皮膜が緻密化されているため高硬度を有する。これらの理由から、高温環境下における動的な摩耗環境においても優れた耐摩耗性を発揮できる。
【０００９】
本発明の硬質皮膜のＳｉにおける化学結合状態は、Ｘ線光電子分光分析により、少なくとも窒化物、酸化物及び金属の各状態が存在し、そのうちＳｉの窒化物の強度比率Ｉ（Ｓｉ−Ｎ）が５２％以上であることが好ましい。この条件を満足する硬質皮膜はＡｌＣｒＳｉ系硬質皮膜の硬度を高めることが可能となり、耐摩耗性に優れ好ましい。本発明の硬質皮膜はナノインデンテーションによる硬度測定法における弾性回復率Ｅが３２％≦Ｅ＜４２％であることが好ましく、皮膜の成膜条件であるバイアス電圧、反応ガス圧やその分圧比、成膜時の基体温度を最適に制御することにより達成できる。Ｅが４２％以上の場合、硬質皮膜の残留圧縮応力が高くなり過ぎてしまい靭性に乏しく、密着性を劣化させる場合があり好ましくない。３２％未満の場合、苛酷な使用環境下において強度不足による異常摩耗が発生し、耐摩耗性が十分でないため、あり好ましくない。好ましいＥの値は３３％から３９％である。本発明の硬質皮膜が優れた密着性、耐高温酸化特性並びに耐摩耗性を発揮する更なる理由は、Ｓｉの添加とＸ線回折における最強回折強度が（２００）面又は（１１１）面に有する結晶質からなることによる。Ｓｉの添加により高硬度化による耐摩耗性の大幅改善が成される。Ｘ線回折における最強回折強度が（２００）面又は（１１１）面に有する結晶質からなることにより、硬質皮膜の剥離や異常摩耗を伴わない密着性の改善、硬質皮膜に靭性を持たせることにも効果的である。
【００１０】
本発明の硬質皮膜は、優れた密着性を有し、例えば金型、工具、耐摩耗部材及び耐熱部材の基体表面に適用した場合も剥離等の問題が生じず、硬質皮膜の耐高温酸化特性並びに耐摩耗性を十分発揮することができる。これは本発明の硬質皮膜と、例えばＦｅ、Ｎｉ、Ｃｏの１種以上を含む基体との組合せ場合、基体上に硬質皮膜がエピタキシャルに成長する為である。好ましい基体は、高速度鋼、ダイス鋼、耐熱鋼、軸受け鋼、オーステナイト系ステンレス、超硬合金、サーメット等が挙げられる。
【００１１】
本発明の硬質皮膜を基体表面に形成する方法としては、アーク放電式イオンプレーティング法がある。硬質皮膜はアーク放電により蒸発源であるカソードからイオン化させたＡｌＣｒＳｉ及び、必要に応じ硼素を目的とする組成となるような各種気体、例えばＮ_２、Ｏ_２、Ｃ_２Ｈ_２等の活性ガス雰囲気中でイオンプレーティングすることによって得ることができ、目的とする皮膜組成より構成されるターゲットを使用すれば、安定した組成の皮膜が得られ易い。ターゲット内に酸素を含有させることによっても、皮膜内に酸素を添加することも可能である。基体にバイアス電圧を印加すると、皮膜と基体の密着性を一段と高めることができる。本発明皮膜の被覆条件は下記に示す条件が好ましく被覆基体により使い分けることが可能である。即ち、ガス圧を１．５〜５．０Ｐａ、被覆基体温度を４５０〜７００℃、バイアス電圧を−１５〜−３００Ｖの低バイアス電圧が好ましく、この範囲であれば密着性、耐高温酸化特性並びに耐摩耗性の優れた緻密な硬質皮膜が得られる。
【００１２】
本発明硬質皮膜の金属成分の４原子％未満を４ａ、５ａ、６ａ族の金属成分の１種以上で置き換えた場合、また本発明に関わる上記組成範囲内での複層構造のおいても同様な効果が確認され好ましく、本発明の技術的範囲に含まれるものである。以下、実施例について説明するが、本発明は下記の実施例に限定されるものではなく、前後の趣旨に沿って適宜変更することは本発明の技術的範囲に含まれるものである。
【００１３】
【実施例】
（実施例１）
本発明に係る硬質皮膜を被覆する被覆条件を検討した結果、Ｘ線光電子分光分析結果及びＸ線回折結果について述べる。被覆基体は鏡面加工したＣｏ含有量１３．５重量％の微粒超硬合金を用い、アーク放電式イオンプレーティング法により成膜した。目標とした組成となるよう粉末法により作成した酸素を含有したＡｌＣｒＳｉ合金ターゲット、ＡｌＣｒＳｉＢ合金ターゲットを用い、窒素ガス、酸素ガス必要に応じアセチレンガスからなる活性ガスを真空装置内に導入しながら全体のガス圧を３．０Ｐａ、バイアス電圧を−１００Ｖ、被覆温度を４５０℃とし、全体の厚みを約５μｍとした。
【００１４】
Ｘ線光電子分光分析は、ＰＨＩ社製１６００Ｓ型Ｘ線光電子分光分析装置を用い、Ｘ線源はＭｇＫαを用い４００Ｗとし、分析領域を直径０．４ｍｍの円内部を分析した。分析前に、硬質皮膜表面に付着した汚染物質等を除去するために５分間Ａｒイオンガンを用いて表面をエッチングした後、ワイドスペクトルを測定し、更に３０秒間エッチングした後、ナロースペクトルを測定した。ＡｒイオンガンによるエッチングレートはＳｉＯ_２換算で１．９ｎｍ／分であった。また、得られた硬質皮膜の組成は電子プローブＸ線マイクロアナリシスおよびオージェ電子分光法により決定した。
上記の条件で（Ａｌ_０．６０Ｃｒ_０．３６Ｓｉ_０．０４）（Ｎ_０．８Ｃ_０．１Ｏ_０．１）を成膜し、本発明例１とした。本発明例１のＸ線光電子分光分析結果によるワイドスペクトルを図１に示す。図１より本発明皮膜にはＳｉとＯのスペクトルの存在が認められ、Ｓｉ−Ｏの結合エネルギーの存在を示す。また、本発明例１のＸ線回折結果を図２に示すが、（２００）面に最も強く配向した結晶質であることが認められる。また、被覆条件は同一でもターゲットに含有される酸素含有量が１８００ｐｐｍであった比較例２の試料には、５３０ｅＶ近傍に酸素との結合を示すピークは確認されなかった。
【００１５】
（実施例２）
試料は、鏡面加工したＣｏ含有量１３．５重量％の微粒超硬合金の基体を用い、アーク放電式イオンプレーティング法により成膜した。Ｘ線光電子分光分析によりＳｉ窒化物、Ｓｉ酸化物、Ｓｉ金属の各強度比率を算出した結果を表１に示す。
【００１６】
【表１】

【００１７】
強度比率は、表１に示す各硬質皮膜のＳｉ２ｐスペクトルのピーク分離を行うことにより算出した。ピーク分離は、Ｓｉ窒化物成分のピーク位置を１０１．２±０．２ｅＶ、Ｓｉ酸化物成分のピーク位置を１０３．３±０．２ｅＶ、Ｓｉ金属成分のピーク位置を９９．３±０．２ｅＶとして、ピークフィッティング法を用いた。本発明例４のＳｉ２ｐのナロースペクトルを図３、本発明例８のＳｉ２ｐのナロースペクトルを図４に示す。表１よりＩ（Ｓｉ−Ｎ）の強度比率が５２％以上となる好ましい被覆条件は、ガス圧が２．０〜５．０Ｐａ程度、バイアス電圧は−１００〜−３００Ｖ、被覆温度が３５０〜５００℃である。Ｉ（Ｓｉ−Ｎ）の強度比率は、被覆条件のみから決定されるものではなく、皮膜組成によっても変動するものである。
【００１８】
（実施例３）
皮膜の耐高温酸化特性を調べるために、Ｃｏ含有量が１３．５重量％からなるＳＮＭＮ４３２の超硬合金基体を用い、表２に示す種々の組成からなる硬質皮膜を被覆した。被覆条件は実施例１と同一条件で被覆した試料を用いた。酸化試験は大気中で１１００℃に保持し、その保持時間を夫々変化させて行い、所定時間経過後の硬質皮膜の酸化層厚さを測定した。即ち酸化層の厚さが厚い程硬質皮膜への酸素の内向拡散が著しいことを示し、耐高温酸化特性に劣ることを意味する。酸化条件並びに各条件下における各硬質皮膜の酸化層の厚さを表２に併記する。表２より、従来例１９は時間経過に伴い酸化が著しく硬質皮膜はすべて酸化物となり酸素の内向拡散が基体まで達していることが確認されるが、本発明例は大幅な酸化進行は確認されず、耐高温酸化特性に優れていることは明らかである。また比較例１６はＡｌ含有量が２０原子％の場合であるが、本発明例に比較して酸化が著しく耐高温酸化特性に劣る。
【００１９】
【表２】

【００２０】
（実施例４）
鏡面加工したＣｏ含有量が１３．５重量％からなるＳＮＭＮ４３２の超硬基体表面に実施例１と同一な被覆条件で硬質皮膜を被覆した試料を用いて、皮膜の硬度測定を行った。試験機は市販の微小押し込み硬さ試験機を用い、圧子はダイヤモンド製の対稜角１１５°のＢｅｒｋｏｖｉｃｈ型三角錐圧子を用い、そのときの最大荷重を４９ｍＮ、荷重負荷ステップ４．９ｍＮ／ｓｅｃ、最大荷重時における保持時間を１ｓｅｃとした。試料は被覆後硬質皮膜断面を斜め５度に０．１μｍのダイヤモンド砥粒により研磨を行い、鏡面加工した硬質皮膜表面の膜厚が３．５μｍの位置で硬度測定を実施した。また硬度ばらつきの影響を考慮して各試料に付き１０点測定しその平均値を測定値とした。本硬度測定では、全被覆層の厚みＫが、荷重に対する最大押し込み深さＬに対して、Ｋ／Ｌ≧１０であるので、被覆基材の影響は受けず、硬質皮膜そのものの硬度であると考えられる。測定結果を表２に併記する。また、同時に薄板の変形量より算出した硬質皮膜の残留圧縮応力を測定した結果についても表２に併記する。
【００２１】
表２より、本発明例は残留応力が従来例１９である（Ａｌ_０．５Ｃｒ_０．５）Ｎ皮膜より低く、従来例１９よりも高硬度を有している。比較例１６はＡｌ含有量が２０原子％の場合であるが、本発明例に比べ皮膜硬度が低いことに加えて、耐高温酸化特性に関しても本発明例に比べ劣る。比較例１７はＳｉ含有量が３０原子％の場合であるが、耐高温酸化特性の改善効果は認められるものの、本発明例に比べ皮膜硬度の改善が十分ではなく耐摩耗性が劣る。比較例１８はＡｌ含有量が８５原子％の場合の比較例であるが、皮膜硬度が低く耐摩耗性が十分ではない。
【００２２】
（実施例５）
実施例１と同一な被覆条件で（Ａｌ_ｘＣｒ_１−ｘＳｉ_０．０５）（ＮＯ）系の皮膜を成膜し、比較例２０、ｘ＝０．２０、比較例２１、ｘ＝０．３０、本発明例２２、ｘ＝０．５０、本発明例２３、ｘ＝０．６０、本発明例２４、ｘ＝０．７０、比較例２５、ｘ＝０．８０、及び（ＡｌｘＣｒ１−ｘ）Ｎ系の従来例２６、ｘ＝０．２０、従来例２７、ｘ＝０．５０、従来例２８、ｘ＝０．７０、を製作し押し込み硬さを測定した。測定方法は、実施例４と同じである。
【００２３】
図５より本発明例２２〜２４、Ａｌ添加量、４５〜７５原子％の範囲でＳｉ及び酸素を含有しない系よりも高硬度を示した。本発明の硬質皮膜は、Ｓｉ及び酸素を含有することにより高硬度となり、４０ＧＰａ以上を得ることが出来る。より好ましい硬度は４５から５５ＧＰａである。これによって密着性並びに耐摩耗性に優れた硬質皮膜が得られる。
【００２４】
（実施例６）
本発明皮膜の密着性を評価するために、研削加工したＣｏ含有量が１３．５重量％からなるＳＮＭＮ４３２の超硬合金の基体表面に実施例１と同一な被覆条件で硬質皮膜を被覆した試料を用いて、硬質皮膜表面からロックウェル硬度計により荷重１４７０Ｎで硬度測定を行い、その圧痕周辺部の剥離状態を光学顕微鏡により観察した。表２に剥離状況を併記する。表２より、従来例１９は被覆基体の塑性変形に追従することができず、何れも圧痕周辺部に膜剥離が発生した。特に被覆基体の硬度低下により、基体の塑性変形量が大きくなるため、その傾向は著しい。一方、本発明例は、何れの被覆基体においても優れた密着性を示した。
【００２５】
（実施例７）
本発明皮膜の耐塑性変形性能特性を調べるためにナノインデンテーション法による硬度測定を実施した。例えば、切削工具における被覆工具材料においては、切削加工時、切刃近傍で切削応力方向に微視的な切刃の塑性変形を伴う。切刃に塑性変形が生じると被覆される硬質皮膜にも応力が作用し、微視的な塑性変形を伴う。この変形に耐えられない硬質皮膜は剥離やクラックを伴い、その部分から異常摩耗や切刃の欠損が生じる。即ち、塑性変形を伴う動的環境下においては硬質皮膜の耐塑性変形性能が重要となる。試料の被覆条件は実施例１と同じ、硬度測定条件に関しては実施例４と同じである。
【００２６】
得られた荷重変位曲線から解析を行った。測定例を以下に示す。本発明皮膜である表２の本発明例１１及び従来例１９の荷重変位曲線を図６に示す。図６より本発明例１１は、最大荷重時における最大変位量が大きく、永久ひずみである塑性変形量が小さく、同一応力が硬質皮膜に作用した際、弾性回復する割合が大きく塑性変形し難いことを示す。この荷重変位曲線から弾性回復率Ｅを求めた。弾性回復率Ｅが大きくなるほど、全変形量に対する弾性回復の寄与する割合が大きくなり、弾性回復特性に優れることを意味する。この値を表２に併記する。表２より、本発明例は従来例に比べて、弾性回復特性に優れていることが明らかであり、摩耗等の応力場が作用する動的環境下においても硬質皮膜の剥離やクラックの発生を低減することが可能となり、密着性に優れた硬質皮膜を得ることができる。本発明例より、より好ましい弾性回復率Ｅとしては３３％から３９％であると言える。
【００２７】
（実施例８）
本発明皮膜の高温安定性を調べるために、実施例１と同一方法で作成した試料を用い、真空中における高温軟化特性の評価を行った。評価方法は１１００℃、１２００℃で夫々４時間保持した後の皮膜硬度を測定した。硬度測定方法は実施例４と同一方法で測定を行った。結果を表２に併記する。
従来例１９は１１００℃で４時間保持した後の皮膜硬度は３５．５ＧＰａ程度であり、ＴｉＮ皮膜とほぼ同等の硬度まで硬度低下が確認された。処理後のＸ線回折結果から、これらは何れもＴｉＮ皮膜に相変態していることを確認した。従来例１９においては、１２００℃で４時間保持したものは被覆基体からＣやＣｏの硬質皮膜内への拡散も確認された。従来例１９に比べ、本発明例は高温環境下においても著しい硬度低下は確認されず、高温環境下においても優れた特性を維持することが可能であった。
【００２８】
【発明の効果】
本発明を適用することにより、皮膜の硬さを向上させることが出来、エンドミル、ドリル等の切削工具や耐摩耗工具に用いても十分な耐摩耗性を有し、密着性、耐高温酸化特性を改善した硬質皮膜を提供できる。これにより近年の切削加工の高能率化に対しても切削寿命を低下させることなく、性能を著しく改善することが可能となり、また高温環境下において耐摩耗性の要求される用途においても飛躍的にその耐久性を向上させることが可能となった。これらの改善により、上記特性が要求される産業上の各分野において大幅な製造コスト低減が可能となった。
【図面の簡単な説明】
【図１】図１は、本発明例のＸ線光電子分光分析結果によるワイドスペクトルプロファイルを示す。
【図２】図２、は本発明例のＸ線回折結果を示す。
【図３】図３は、本発明例のＸ線光電子分光分析によるナロースペクトルプロファイルを示す。
【図４】図４は、本発明例のＸ線光電子分光分析によるナロースペクトルプロファイルを示す。
【図５】図５は、本発明例と従来例とのＡｌ添加量と皮膜硬度の関係を示す。
【図６】図６は、本発明例及び従来例との荷重変位曲線を示す。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a hard coating for coating the surface of a cutting tool, or a hard coating for coating a surface of a wear-resistant member requiring high hardness such as a mold, a bearing, a die, a roll, or a heat-resistant member such as an internal combustion engine part. The present invention relates to a hard coating that covers the surface.
[0002]
[Prior art]
AlCr-based coatings are disclosed in Japanese Patent No. 3027502, Japanese Patent No. 3039381 and Japanese Patent Application Laid-Open No. 2002-160129 as hard coating materials having excellent resistance to high-temperature oxidation. Japanese Patent No. 3027502 discloses a case relating to an amorphous film having high hardness among AlCr-based hard films selected from AlCr and one of C, N, and O as a metal component. However, the hardness of this amorphous film is at most about 21 GPa, the Knoop hardness, and abrasion resistance cannot be expected, and adhesion is not sufficient. The hard coating disclosed in Japanese Patent No. 3039381 and JP-A-2002-160129 is a nitride of AlCr, and has a high-temperature oxidation resistance of about 1000 ° C., but has an oxidation resistance of 1000 ° C. or more. Has not been considered. The hardness is about HV21 GPa and the improvement of the hardness is insufficient and the wear resistance is poor.
[0003]
[Problems to be solved by the invention]
The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a hard coating having excellent high-temperature oxidation resistance, high hardness, and extremely excellent adhesion to a substrate.
[0004]
[Means for solving the problem]
The hard film according to the present invention were able to achieve the above object, a hard film is coated by arc discharge type ion plating method, the rigid coating _{_{(Al x Cr 1-x-}} y Si y) ( _{N 1-α-β-γ} B α C β O γ), where, x, y, α, β , γ represents a respective atomic ratio, 0.45 <X <0.75,0 <y <0. 20, 0 ≦ α <0.12, 0 ≦ β <0.20, 0 <γ <0.25, and at least Cr, Al and / or Si and oxygen in the range of 525 eV to 535 eV in X-ray photoelectron spectroscopy. A hard coating characterized by having binding energy with As a result, it was found that the adhesion to the substrate and the high-temperature oxidation resistance were improved, and the present invention was completed.
[0005]
Further, in the hard coating of the present invention, the chemical bonding state of Si in the hard coating is determined by X-ray photoelectron spectroscopy at least in the states of nitride, oxide and metal, and the strength ratio of nitride of Si is determined. I (Si-N), the intensity ratio of the oxide of Si is I (Si-O), and the intensity ratio of the metal of Si is I (Si), where I (Si-N) + I (Si-O) + I ( Si) = 100%, and I (Si—N) of 52% or more is effective for increasing the hardness of the hard coating and is preferable. For the hard coating, a contact depth calculated from a contact stiffness of a load removal curve and a maximum change amount at a maximum load are obtained by a hardness measurement method using nanoindentation (WC Oliverland, GM Phar: J). Mater Res., Vol.7, No. 6, June 1992 1565-1584). Using this numerical value, E = 100 − {(contact depth) / (maximum displacement at maximum load)}
By defining the elastic recovery ratio E by the following formula, and satisfying 32% ≦ E <42%, the balance between abrasion resistance and adhesion is optimized, which is preferable. The hard coating is a hard coating characterized by having the strongest diffraction intensity in X-ray diffraction on the (200) plane or the (111) plane.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
The present inventor has conducted research with the aim of obtaining a hard film having excellent adhesion to a substrate and excellent high-temperature oxidation resistance and high hardness. As a result, the composition of the hard film and the film forming conditions such as bias voltage and reaction gas pressure were investigated. The hard coating of the present invention, which achieves the object, was completed by examining the pressure ratio and the substrate temperature during film formation. By coating the hard coating of the present invention with an arc discharge ion plating, the toughness, which is a plastic deformation resistance, which is a problem in a severe wear environment, is remarkably improved. Thus, even when applied to the substrate surface of, for example, a mold, a tool, a wear-resistant member, and a heat-resistant member, there is no problem such as peeling, and the high-temperature oxidation resistance and wear resistance of the hard coating are sufficiently exhibited.
[0007]
The composition of the metal elements constituting the hard coating of the present _invention, satisfying the _{(Al x Cr 1-x-} y Si y) x 0.45 in <x <0.75, y is 0 <y <0.20 There is a need to. When the value of x is 0.45 or less and the value of y is 0, the effect of improving the film hardness and the high-temperature oxidation resistance is not sufficient. When the value of x is 0.75 or more and the value of y is 0.20 or more, In some cases, the residual compressive stress becomes excessive and induces self-destruction immediately after coating. At the same time, a hexagonal crystal may be observed at the same time, and the strength rapidly decreases. The alpha of the nonmetallic element of _{(N 1-α-β-} γ B α C β O γ), embrittlement of the film was confirmed by 0.12 or more. A preferable upper limit of α is 0.08. The addition of boron is preferred because it has the effect of reducing the adhesion to the workpiece and the coefficient of friction in a high-temperature environment. When β was 0.20 or more, embrittlement of the film was confirmed. The preferred upper limit of β is 0.16. The addition of carbon increases the hardness of the hard coating and is effective in reducing the coefficient of friction at room temperature. γ must be greater than 0 and less than 0.25. When γ is 0.25 or more, the hardness of the film is remarkably reduced, and the wear resistance is poor. A preferred value of γ is 0.02 or more and 0.20 or less. The ratio of N, B, C, O of the nonmetallic element to Al, Cr, Si of the metal element is stoichiometrically ((N, B, C, O) / (Al, Cr, Si)> 1.1) Is more preferred.
[0008]
In X-ray photoelectron spectroscopy, it is necessary to have a binding energy between Cr, Al and / or Si and oxygen between 525 eV and 535 eV. In a high-temperature oxidizing atmosphere, the inward diffusion of oxygen can be remarkably suppressed by obscuring a crystal grain boundary serving as a diffusion path of oxygen. In a high-temperature oxidizing environment, formation of an Al and Cr oxidation protective layer containing extremely dense Si on the outermost surface of the hard coating also greatly contributes to suppression of oxidation. This is because the oxide formed on the very outermost surface is less likely to cause layer separation than, for example, TiO ₂ , Al ₂ O ₃ , and Cr ₂ O ₃ formed of an AlTi-based hard film or an AlCr-based hard film. . Regarding the hardness of the coating, Cr, Al and / or Si are present in a state of nitride, oxide or oxynitride, and have high hardness because the coating is densified. For these reasons, excellent wear resistance can be exhibited even in a dynamic wear environment under a high temperature environment.
[0009]
According to the X-ray photoelectron spectroscopy, the chemical bonding state of Si in the hard coating of the present invention includes at least each state of nitride, oxide, and metal, and among them, the intensity ratio I (Si-N) of the nitride of Si is It is preferably at least 52%. A hard coating that satisfies this condition can increase the hardness of the AlCrSi-based hard coating, and is preferred because it has excellent wear resistance. The hard coating of the present invention preferably has an elastic recovery rate E in a hardness measurement method by nanoindentation of 32% ≦ E <42%, and includes a bias voltage, a reaction gas pressure and a partial pressure ratio thereof, which are the film forming conditions. This can be achieved by optimally controlling the substrate temperature during film formation. If E is at least 42%, the residual compressive stress of the hard coating will be too high, resulting in poor toughness and poor adhesion, which is not preferable. If it is less than 32%, abnormal wear occurs due to insufficient strength in a severe use environment, and the wear resistance is not sufficient, which is not preferable. Preferred values of E are from 33% to 39%. A further reason why the hard coating of the present invention exhibits excellent adhesion, high-temperature oxidation resistance and abrasion resistance is that the addition of Si and the strongest diffraction intensity in X-ray diffraction are in the (200) plane or the (111) plane. Due to being crystalline. By the addition of Si, the wear resistance is greatly improved by increasing the hardness. By using a crystalline material having the strongest diffraction intensity in the (200) plane or (111) plane in X-ray diffraction, it is possible to improve the adhesion without peeling or abnormal wear of the hard film and to impart toughness to the hard film. Is also effective.
[0010]
The hard coating of the present invention has excellent adhesion, for example, when applied to the substrate surface of a mold, a tool, a wear-resistant member and a heat-resistant member, does not cause problems such as peeling, and the high-temperature oxidation resistance of the hard coating. In addition, the wear resistance can be sufficiently exhibited. This is because when the hard film of the present invention is combined with a substrate containing, for example, one or more of Fe, Ni, and Co, the hard film grows epitaxially on the substrate. Preferred substrates include high-speed steel, die steel, heat-resistant steel, bearing steel, austenitic stainless steel, cemented carbide, cermet, and the like.
[0011]
As a method for forming the hard coating of the present invention on the surface of the substrate, there is an arc discharge type ion plating method. The hard film is made of AlCrSi ionized from a cathode serving as an evaporation source by arc discharge and, if necessary, an atmosphere of an active gas such as N ₂ , O ₂ , C ₂ H ₂ such as N ₂ , O ₂ , C ₂ H ₂ or the like. It can be obtained by ion plating in the inside, and if a target composed of a target film composition is used, a film having a stable composition can be easily obtained. It is also possible to add oxygen to the film by containing oxygen in the target. When a bias voltage is applied to the substrate, the adhesion between the film and the substrate can be further enhanced. The coating conditions of the coating of the present invention are preferably the following conditions, and can be properly selected depending on the coated substrate. That is, the gas pressure is preferably 1.5 to 5.0 Pa, the coated substrate temperature is 450 to 700 ° C., and the bias voltage is preferably a low bias voltage of −15 to −300 V. A dense hard film with excellent wear resistance can be obtained.
[0012]
The same applies when less than 4 atomic% of the metal component of the hard coating of the present invention is replaced by one or more of the metal components of groups 4a, 5a and 6a, and also in the case of a multilayer structure within the above composition range according to the present invention. These effects are confirmed and preferred, and are included in the technical scope of the present invention. Hereinafter, although an Example is described, the present invention is not limited to the following Examples, and it is included in the technical scope of the present invention to change appropriately according to the meaning before and after.
[0013]
【Example】
(Example 1)
As a result of examining the coating conditions for coating the hard coating according to the present invention, the results of X-ray photoelectron spectroscopy and the results of X-ray diffraction will be described. The coated substrate was formed by arc discharge ion plating using a fine-grained cemented carbide having a Co content of 13.5% by weight which was mirror-finished. Using an oxygen-containing AlCrSi alloy target and an AlCrSiB alloy target prepared by a powder method so as to have a target composition, nitrogen gas and oxygen gas are introduced into the vacuum apparatus as needed while introducing an active gas comprising acetylene gas into the vacuum apparatus. The gas pressure was 3.0 Pa, the bias voltage was -100 V, the coating temperature was 450 ° C., and the total thickness was about 5 μm.
[0014]
The X-ray photoelectron spectroscopy analysis was performed using a 1600S type X-ray photoelectron spectrometer manufactured by PHI, the X-ray source was 400 W using MgKα, and the analysis area was analyzed inside a circle having a diameter of 0.4 mm. Before the analysis, the surface was etched using an Ar ion gun for 5 minutes to remove contaminants and the like adhering to the hard film surface, a wide spectrum was measured, and after further etching for 30 seconds, a narrow spectrum was measured. The etching rate by the Ar ion gun was 1.9 nm / min in terms of SiO ₂ . The composition of the obtained hard coating was determined by electron probe X-ray microanalysis and Auger electron spectroscopy.
In the above conditions the _{_{_{_{(Al 0.6 0Cr 0.36 Si 0.04)}}}} (N 0.8 C 0.1 O 0.1) was deposited, and the present invention Example 1. FIG. 1 shows a wide spectrum according to the result of X-ray photoelectron spectroscopy of Example 1 of the present invention. FIG. 1 shows that the film of the present invention has the spectra of Si and O, indicating the presence of the binding energy of Si—O. FIG. 2 shows the result of X-ray diffraction of Example 1 of the present invention, and it is confirmed that the crystalline material was most strongly oriented on the (200) plane. Further, in the sample of Comparative Example 2 in which the oxygen content contained in the target was 1800 ppm even under the same coating conditions, no peak indicating binding to oxygen was observed at around 530 eV.
[0015]
(Example 2)
The sample was formed by an arc discharge ion plating method using a mirror-finished substrate of a fine-grained cemented carbide having a Co content of 13.5% by weight. Table 1 shows the results of calculating the respective intensity ratios of Si nitride, Si oxide, and Si metal by X-ray photoelectron spectroscopy.
[0016]
[Table 1]

[0017]
The intensity ratio was calculated by performing peak separation of the Si2p spectrum of each hard coating shown in Table 1. The peak separation was as follows: the peak position of the Si nitride component was 101.2 ± 0.2 eV, the peak position of the Si oxide component was 103.3 ± 0.2 eV, and the peak position of the Si metal component was 99.3 ± 0.2 eV. The peak fitting method was used. FIG. 3 shows the narrow spectrum of Si2p of Example 4 of the present invention, and FIG. 4 shows the narrow spectrum of Si2p of Example 8 of the present invention. As shown in Table 1, preferred coating conditions under which the intensity ratio of I (Si-N) is 52% or more are as follows: gas pressure is about 2.0 to 5.0 Pa, bias voltage is -100 to -300 V, and coating temperature is 350 to 500. ° C. The intensity ratio of I (Si-N) is not determined only by the coating conditions, but also varies depending on the coating composition.
[0018]
(Example 3)
In order to examine the high-temperature oxidation resistance of the coating, a hard coating having various compositions shown in Table 2 was coated using a cemented carbide substrate of SNMN432 having a Co content of 13.5% by weight. A sample coated under the same conditions as in Example 1 was used. The oxidation test was carried out at 1100 ° C. in the air and the holding time was varied, and the thickness of the oxidized layer of the hard coating after a predetermined time was measured. That is, as the thickness of the oxide layer is larger, the inward diffusion of oxygen into the hard coating is more remarkable, which means that the high-temperature oxidation resistance is inferior. Table 2 also shows the oxidation conditions and the thickness of the oxide layer of each hard coating under each condition. From Table 2, it can be confirmed that, in the conventional example 19, the hard coating was remarkably oxidized with the lapse of time, and all the hard films became oxides, and the inward diffusion of oxygen reached the substrate. Thus, it is clear that the high-temperature oxidation resistance is excellent. Comparative Example 16 was a case where the Al content was 20 atomic%, but was significantly oxidized and inferior in high-temperature oxidation resistance as compared with the present invention.
[0019]
[Table 2]

[0020]
(Example 4)
The hardness of the coating was measured using a sample obtained by coating a hard coating of SNMN432 having a Co content of 13.5% by weight and having a mirror-finished surface under the same coating conditions as in Example 1. The tester used was a commercially available microindentation hardness tester, and the indenter used was a Berkovich-type triangular pyramid indenter made of diamond with a 115 ° conical angle, with a maximum load of 49 mN and a load step of 4.9 mN / sec. The holding time under load was set to 1 sec. After coating the sample, the cross section of the hard coating was polished obliquely at 5 degrees with diamond abrasive grains of 0.1 μm, and the hardness was measured at a position where the thickness of the mirror-finished hard coating surface was 3.5 μm. Also, considering the influence of hardness variation, 10 points were measured for each sample, and the average value was used as the measured value. In this hardness measurement, since the thickness K of all the coating layers is K / L ≧ 10 with respect to the maximum indentation depth L with respect to the load, the hardness K is not affected by the coating base material and is the hardness of the hard coating itself. Conceivable. The measurement results are also shown in Table 2. Table 2 also shows the results of measuring the residual compressive stress of the hard coating calculated from the deformation of the thin plate at the same time.
[0021]
As shown in Table 2, the present invention example has a lower residual stress than the (Al _0.5 Cr _0.5 ) N film of the conventional example 19, and has a higher hardness than the conventional example 19. Comparative Example 16 was a case where the Al content was 20 atomic%, but in addition to the film hardness being lower than that of the present invention, the high temperature oxidation resistance was also inferior to that of the present invention. Comparative Example 17 is a case where the Si content is 30 atom%. Although the effect of improving the high-temperature oxidation resistance is observed, the film hardness is not sufficiently improved and the wear resistance is inferior to the examples of the present invention. Comparative Example 18 is a comparative example in which the Al content is 85 atomic%, but the film hardness is low and the wear resistance is not sufficient.
[0022]
(Example 5)
A film of _{_{_{(Al x Cr 1-x Si}}} 0.05) (NO) system under the same coating conditions as in Example 1 was formed, Comparative Example 20, x = 0.20, Comparative Example 21, x = 0. 30, Inventive Example 22, x = 0.50, Inventive Example 23, x = 0.60, Inventive Example 24, x = 0.70, Comparative Example 25, x = 0.80, and (AlxCr1-x ) N-type conventional example 26, x = 0.20, conventional example 27, x = 0.50, conventional example 28, x = 0.70 were manufactured, and the indentation hardness was measured. The measuring method is the same as that of the fourth embodiment.
[0023]
As shown in FIG. 5, in Examples 22 to 24 of the present invention, in the range of Al addition amount of 45 to 75 atomic%, the hardness was higher than that of the system containing neither Si nor oxygen. The hard coating of the present invention becomes high hardness by containing Si and oxygen, and can obtain 40 GPa or more. More preferred hardness is 45 to 55 GPa. As a result, a hard coating excellent in adhesion and abrasion resistance can be obtained.
[0024]
(Example 6)
In order to evaluate the adhesion of the coating of the present invention, a sample in which a hard coating was coated under the same coating conditions as in Example 1 on a substrate surface of a cemented SNMN432 alloy having a Co content of 13.5% by weight which had been ground and processed. The hardness was measured from the surface of the hard film with a load of 1470 N using a Rockwell hardness meter, and the peeling state around the indentation was observed with an optical microscope. Table 2 also shows the peeling state. From Table 2, it can be seen that Conventional Example 19 could not follow the plastic deformation of the coated substrate, and in each case, film peeling occurred around the indentation. In particular, the tendency is remarkable because the amount of plastic deformation of the substrate increases due to a decrease in the hardness of the coated substrate. On the other hand, the examples of the present invention showed excellent adhesion to any of the coated substrates.
[0025]
(Example 7)
Hardness was measured by a nanoindentation method in order to examine the plastic deformation resistance characteristics of the coating of the present invention. For example, a coated tool material of a cutting tool involves microscopic plastic deformation of the cutting edge in the direction of cutting stress near the cutting edge during cutting. When plastic deformation occurs on the cutting edge, stress also acts on the hard film to be coated, and microscopic plastic deformation is accompanied. The hard film that cannot withstand this deformation is accompanied by peeling and cracks, and abnormal wear and chipping of the cutting edge occur from that portion. That is, in a dynamic environment accompanied by plastic deformation, the plastic film's plastic deformation resistance becomes important. The coating conditions of the sample are the same as in Example 1, and the hardness measurement conditions are the same as in Example 4.
[0026]
Analysis was performed from the obtained load displacement curve. A measurement example is shown below. FIG. 6 shows the load displacement curves of Example 11 of the present invention and Conventional Example 19 in Table 2 which are the films of the present invention. As shown in FIG. 6, Example 11 of the present invention has a large maximum displacement under a maximum load, a small amount of plastic deformation, which is a permanent set, and a large elastic recovery ratio when the same stress acts on a hard coating. Is shown. The elastic recovery rate E was obtained from the load displacement curve. As the elastic recovery rate E increases, the contribution ratio of the elastic recovery to the total deformation increases, which means that the elastic recovery characteristics are excellent. This value is also shown in Table 2. From Table 2, it is apparent that the present invention example is superior to the conventional example in the elastic recovery characteristics, and the hard coating peels and cracks occur even under a dynamic environment where a stress field such as abrasion acts. This makes it possible to obtain a hard coating having excellent adhesion. From the examples of the present invention, it can be said that the more preferable elastic recovery ratio E is 33% to 39%.
[0027]
(Example 8)
In order to examine the high-temperature stability of the coating of the present invention, the sample prepared by the same method as in Example 1 was used to evaluate the high-temperature softening characteristics in a vacuum. The evaluation method was to measure the film hardness after holding at 1100 ° C. and 1200 ° C. for 4 hours, respectively. The hardness was measured in the same manner as in Example 4. The results are also shown in Table 2.
In Conventional Example 19, the film hardness after holding at 1100 ° C. for 4 hours was about 35.5 GPa, and it was confirmed that the hardness decreased to almost the same hardness as the TiN film. From the results of the X-ray diffraction after the treatment, it was confirmed that each of them was transformed into a TiN film. In Conventional Example 19, when the sample was held at 1200 ° C. for 4 hours, diffusion of C and Co into the hard coating from the coated substrate was also confirmed. Compared with Conventional Example 19, the present invention example did not show a significant decrease in hardness even in a high temperature environment, and was able to maintain excellent characteristics even in a high temperature environment.
[0028]
【The invention's effect】
By applying the present invention, the hardness of the coating can be improved, and it has sufficient abrasion resistance even when used for cutting tools such as end mills and drills and abrasion resistance tools, adhesion, and high-temperature oxidation resistance. Can be provided. This makes it possible to significantly improve the performance without reducing the cutting life, even in recent years with high efficiency of cutting, and also dramatically improves the wear resistance in high temperature environments. Its durability can be improved. These improvements have made it possible to significantly reduce manufacturing costs in various industrial fields requiring the above characteristics.
[Brief description of the drawings]
FIG. 1 shows a wide-spectrum profile based on the results of X-ray photoelectron spectroscopy analysis of an example of the present invention.
FIG. 2 shows an X-ray diffraction result of the present invention.
FIG. 3 shows a narrow spectrum profile by X-ray photoelectron spectroscopy of the example of the present invention.
FIG. 4 shows a narrow spectrum profile by X-ray photoelectron spectroscopy of the example of the present invention.
FIG. 5 shows the relationship between the amount of Al added and the film hardness between the present invention example and the conventional example.
FIG. 6 shows load displacement curves of the present invention example and the conventional example.

Claims

アーク放電式イオンプレーティング法により被覆される硬質皮膜であって、該硬質皮膜は（Ａｌ_ｘＣｒ_{１−ｘ−ｙ}Ｓｉ_ｙ）（Ｎ_{１−α−β−γ}Ｂ_αＣ_βＯ_γ）、但し、ｘ、ｙ、α、β、γは夫々原子比率を示し、０．４５＜Ｘ＜０．７５、０＜ｙ＜０．２０、０≦α＜０．１２、０≦β＜０．２０、０＜γ＜０．２５からなり、Ｘ線光電子分光分析における５２５ｅＶから５３５ｅＶの範囲に少なくともＣｒ、Ａｌ及び／又はＳｉと酸素との結合エネルギーを有することを特徴とする硬質皮膜。A hard film to be coated by arc discharge type ion plating method, the rigid coating _{_{_{(Al x Cr 1-x-}}} y Si y) (N 1-α-β-γ B α C β O γ), Here, x, y, α, β, and γ each indicate an atomic ratio, and 0.45 <X <0.75, 0 <y <0.20, 0 ≦ α <0.12, 0 ≦ β <0. 20, a hard film comprising 0 <γ <0.25 and having at least a binding energy between Cr, Al and / or Si and oxygen in the range of 525 eV to 535 eV in X-ray photoelectron spectroscopy.

請求項１記載の硬質皮膜において、該硬質皮膜のＳｉの化学結合状態は、Ｘ線光電子分光分析により、少なくとも窒化物、酸化物及び金属の各状態が存在し、Ｓｉの窒化物の強度比率をＩ（Ｓｉ−Ｎ）、Ｓｉの酸化物の強度比率をＩ（Ｓｉ−Ｏ）、Ｓｉの金属の強度比率をＩ（Ｓｉ）、但し、Ｉ（Ｓｉ−Ｎ）＋Ｉ（Ｓｉ−Ｏ）＋Ｉ（Ｓｉ）＝１００％を示し、Ｉ（Ｓｉ−Ｎ）が５２％以上であることを特徴とする硬質皮膜。The hard coating according to claim 1, wherein the chemical bonding state of Si in the hard coating includes at least a nitride, an oxide, and a metal state by X-ray photoelectron spectroscopy. I (Si-N), the intensity ratio of the oxide of Si is I (Si-O), and the intensity ratio of the metal of Si is I (Si), where I (Si-N) + I (Si-O) + I ( Si) = 100%, and I (Si-N) is 52% or more.

請求項１乃至請求項２記載の硬質皮膜において、該硬質皮膜はナノインデンテーションによる硬度測定により求められる弾性回復率Ｅが、３２％≦Ｅ＜４２％であることを特徴とする硬質皮膜。3. The hard coating according to claim 1, wherein the hard coating has an elastic recovery ratio E of 32% ≦ E <42% determined by hardness measurement by nanoindentation.

請求項１乃至請求項３記載の硬質皮膜において、該硬質皮膜はＸ線回折における最強回折強度が（２００）面又は（１１１）面に有する結晶質からなることを特徴とする硬質皮膜。4. The hard coating according to claim 1, wherein the hard coating is made of a crystalline material having the strongest diffraction intensity in the (200) plane or the (111) plane in X-ray diffraction.