JP2006111890A - Coated cemented carbide member and method for producing cemented carbide containing rare earth element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated cemented carbide member excellent in properties of heat resistance and plastic deformation resistance by markedly improving the heat resistance and plastic deformation resistance in a binder phase of a coated cemented carbide tool etc. <P>SOLUTION: In the coated cemented carbide member, the surface of a cemented carbide member is coated with a hard single-layer or multilayer film, and a hard-phase-depleted surface zone where the hard phase is dissipated or decreased is present over the region of 1 to 100 μm in a depth direction from the surface of the member right under the film, and further, a hard-phase-enriched intermediate zone is present over the region of 1 to 200 μm in a depth direction adjacently to the hard-phase-depleted surface zone. Moreover, in the coated cemented carbide member, rare earth elements are contained in the binder phase and the amount of oxygen in the region where the rare earth elements are present is 0 to 5 mass%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、切削工具などに使用される被覆超硬合金部材と希土類元素含有超硬合金の製造方法に関するものである。   The present invention relates to a coated cemented carbide member used for a cutting tool or the like and a method for producing a rare earth element-containing cemented carbide.

超硬合金は、硬度、耐摩耗と靭性のバランスが良く、切削工具や耐摩耗工具、金型、耐熱耐摩耗用部材等に愛用されている。更に、超硬合金製部材の表面に炭窒化チタンや酸化アルミニウムなどの皮膜を被覆した被覆超硬合金工具は、部材の靭性と皮膜の耐摩耗性とが兼備されているため、鋼、鋳物などの切削加工用高能率切削工具として広く用いられている。近年、切削加工の高効率化、切削速度の高速化により、切削工具には高温における耐摩耗性と耐塑性変形性、耐欠損性が要求されている。耐摩耗性と耐欠損性という相反する特性を両立させるため、超硬合金の最表面に鉄族金属の量が合金内部に比べて多い層（結合相富化層）を有するもの、超硬合金の最表面に実質的にＷＣと結合金属のみからなる層（脱β層）を有するもの、あるいは合金内部に比べて硬度が低下した領域（硬度低下層）を有するものを部材とすることが提案されている。これらの具体的な例として、以下の特許文献１、２が開示されている。
特許文献１は、被覆超硬合金部材の切刃稜線部を含めた部材最表面にＷＣ及び鉄族金属のみからなる表層領域を有し、これに隣接して５ａ族金属成分がそれよりも内側の領域に比べて多く含まれている被覆超硬合金部材が提案されている。
特許文献２は、部材表面に軟質表面帯域が存在し、更にこれに隣接して硬質中間帯域が存在する被覆工具が提案されている。しかし、上記特許文献１、２に開示されている従来技術では、部材表面の高靭性層とその直下の高硬度層により、部材の靭性と耐摩耗性を確保しようとしているが、結合相の耐熱、耐塑性変形、耐摩耗性が考慮されておらず、また、硬質相の耐摩耗性が十分でなく、部材全体の耐塑性変形性と耐摩耗性が十分でないという欠点がある。
また、超硬合金の強度と耐熱性を更に高める一つの方策として、希土類元素を添加することにより超硬合金性部材そのものの強度と耐熱安定性を飛躍的に向上させることが検討されているが、未だに実用化されていないのが実状である。その具体的な例として、特許文献３〜６が開示されている。
特許文献３は、希土類元素量を結合金属の０．１〜１０重量％だけ添加することにより、結合相と硬質相のぬれ性を改善し、Ｍｏの酸化と昇華を防いだＭｏを含む硬質合金が開示されている。しかし、希土類元素を金属形状で添加しているため、硬質合金の原料粉末をボールミルで混合するときに酸化されてしまう欠点がある。
特許文献４は、希土類元素がＣｏの０．０１〜０．５％だけ結合相中に固溶して、耐酸化性、耐熱性と高温耐食性が向上した炭化タングステン基超硬合金が開示されている。また、希土類元素を窒化物又はＣｏやＮｉなどとの化合物の形で配合するのが望ましいことが開示されている。希土類金属を窒化物、又はＣｏ及びＮｉなどとの化合物の形で配合することが望ましいことが記述されてはいるが、実際には希土類元素を希土類金属の窒化物や金属粉末の形でのみ配合しており、製造工程中で希土類元素が酸化されてしまう欠点がある。
特許文献５は、Ｔｉ、Ｚｒ、Ｈｆ、Ｔａ、Ｎｂ、Ｖ、Ｃｒ、Ｍｏ、希土類元素等からなる改質物質を焼結合金の表面から濃度勾配を持たせて拡散させることにより、焼結合金表面の耐塑性変形性と耐摩耗性を向上させた改質焼結合金、被覆焼結合金及びその製造方法が開示されている。改質物質として、（Ｄｙ、Ｙ）の酸化物からなる相互固溶体をあげ、酸化イットリウム、酸化ジスプロシウムが改質物質の効果が高くなり好ましいと開示しているように、希土類の酸化物を好ましいものとしている。また、希土類元素を単一物質、炭化物、窒化物、酸化物と他元素との相互固溶体のみで配合しており、希土類元素とＣｏとの化合物は検討もしていない。
特許文献６は、希土類元素とイオウ元素及び／又は希土類元素とイオウ元素と酸素元素とでなる分散物質を、硬質焼結合金全体に対して０．１〜１０体積％含有した硬質焼結合金が開示されている。Ｙ２Ｏ２Ｓ、Ｌａ２Ｏ２Ｓ、Ｃｅ４Ｏ４Ｓ等の希土類の酸化物を積極的添加し、希土類元素の酸化を防止することを検討していない。しかし、特許文献３〜６に開示されている従来技術では、酸素との親和力が強く容易に酸化してしまう特徴を有する希土類元素の酸化を防止する手段が発明されていないために、配合粉の混合工程等で希土類元素が酸化してしまい、所期の特性が得られなくなる欠点がある。 Cemented carbide has a good balance of hardness, wear resistance and toughness, and is favored by cutting tools, wear resistant tools, molds, heat and wear resistant members and the like. Furthermore, coated cemented carbide tools with a coating of titanium carbide, aluminum oxide, etc. on the surface of a cemented carbide member have both the toughness of the component and the wear resistance of the coating, so steel, castings, etc. It is widely used as a high-efficiency cutting tool for cutting. In recent years, cutting tools have been required to have high-temperature wear resistance, plastic deformation resistance, and fracture resistance due to high cutting efficiency and high cutting speed. In order to achieve both conflicting properties of wear resistance and fracture resistance, the outermost surface of the cemented carbide has a layer of iron group metal (bonded phase enriched layer) larger than the inside of the alloy, cemented carbide It is proposed to use a member having a layer (de-β layer) substantially consisting only of WC and a binding metal on the outermost surface of the alloy or a member having a region where the hardness is reduced compared to the inside of the alloy (hardness reduction layer). Has been. The following patent documents 1 and 2 are disclosed as specific examples of these.
Patent Document 1 has a surface layer region composed only of WC and iron group metal on the outermost surface of the member including the cutting edge ridge line part of the coated cemented carbide member, and adjacent to this, the group 5a metal component is located on the inner side. Coated cemented carbide members that are included in a larger amount than the above region have been proposed.
Patent Document 2 proposes a coated tool in which a soft surface zone exists on the surface of a member and a hard intermediate zone exists adjacent to the soft surface zone. However, in the conventional techniques disclosed in Patent Documents 1 and 2 described above, the toughness and wear resistance of the member are to be ensured by the high toughness layer on the surface of the member and the high hardness layer immediately below the high toughness layer. However, there is a drawback that the plastic deformation and wear resistance are not taken into consideration, the wear resistance of the hard phase is not sufficient, and the plastic deformation resistance and wear resistance of the entire member are not sufficient.
In addition, as a measure to further increase the strength and heat resistance of the cemented carbide, it has been studied to drastically improve the strength and heat stability of the cemented carbide member itself by adding rare earth elements. The reality is that it has not yet been put to practical use. As specific examples, Patent Documents 3 to 6 are disclosed.
Patent Document 3 discloses a hard alloy containing Mo that improves the wettability of the binder phase and the hard phase by adding rare earth elements in an amount of 0.1 to 10% by weight of the binder metal, and prevents oxidation and sublimation of Mo. Is disclosed. However, since the rare earth element is added in the form of a metal, there is a drawback that it is oxidized when the raw powder of the hard alloy is mixed by a ball mill.
Patent Document 4 discloses a tungsten carbide-based cemented carbide in which rare earth elements are solid-dissolved in a binder phase by 0.01 to 0.5% of Co, thereby improving oxidation resistance, heat resistance, and high temperature corrosion resistance. Yes. It is also disclosed that it is desirable to blend rare earth elements in the form of nitrides or compounds such as Co or Ni. Although it is described that it is desirable to blend rare earth metals in the form of nitrides or compounds such as Co and Ni, actually rare earth elements are blended only in the form of rare earth metal nitrides or metal powders. However, there is a drawback that rare earth elements are oxidized during the manufacturing process.
Patent Document 5 discloses a sintered alloy by diffusing a reforming material made of Ti, Zr, Hf, Ta, Nb, V, Cr, Mo, rare earth elements or the like with a concentration gradient from the surface of the sintered alloy. A modified sintered alloy, a coated sintered alloy having improved surface plastic deformation resistance and wear resistance, and a method for producing the same are disclosed. As the modifying substance, a mutual solid solution composed of an oxide of (Dy, Y) is cited, and yttrium oxide and dysprosium oxide are preferred as rare earth oxides as disclosed that the effect of the modifying substance is enhanced and preferred. It is said. In addition, rare earth elements are blended only with a single substance, carbide, nitride, or a mutual solid solution of an oxide and another element, and a compound of rare earth elements and Co is not studied.
Patent Document 6 discloses a hard sintered alloy containing 0.1 to 10% by volume of a dispersed material composed of rare earth elements and sulfur elements and / or rare earth elements, sulfur elements and oxygen elements with respect to the entire hard sintered alloy. It is disclosed. It has not been studied to actively add rare earth oxides such as Y2O2S, La2O2S, and Ce4O4S to prevent oxidation of rare earth elements. However, in the prior art disclosed in Patent Documents 3 to 6, since a means for preventing the oxidation of rare earth elements having a strong affinity with oxygen and easily oxidizing is not invented, There is a disadvantage that rare earth elements are oxidized in the mixing step or the like, and desired characteristics cannot be obtained.

特許第３２３５２５９号公報Japanese Patent No. 3235259 特許第３３３１９１６号公報Japanese Patent No. 3333116 特開昭５５−１４１５４３号公報JP-A-55-141543 特開昭５８−３１０６１号公報JP 58-31061 A 特開２０００−３３６４５１公報JP 2000-336451 A 特開２０００−１６０２７６公報JP 2000-160276 A

本発明が解決しようとする課題は、結合相の耐熱、耐塑性変形性を格段に高めることにより、この特性の優れた被覆超硬合金部材を実現し、工具寿命の長い被覆超硬合金工具等を提供することである。また、元来酸化されやすい希土類元素を実質的に酸化させることなく結合相中に含有させる希土類元素含有超硬合金の製造方法を提供することである。   The problem to be solved by the present invention is to realize a coated cemented carbide member having excellent characteristics by significantly improving the heat resistance and plastic deformation resistance of the binder phase, and to provide a coated cemented carbide tool having a long tool life, etc. Is to provide. Another object of the present invention is to provide a method for producing a rare earth element-containing cemented carbide in which a rare earth element that is easily oxidized is contained in a binder phase without being substantially oxidized.

本発明は、主に鉄族金属からなる結合相と、周期律表４ａ、５ａ、６ａ族金属から選択されるＷ以外の少なくとも１種以上の炭化物固溶体、窒化物固溶体、炭窒化物固溶体の少なくとも１種以上を含有する硬質相、及び残ＷＣと不可避不純物とから成る超硬合金部材の表面に、硬質皮膜が単層又は多重層被覆されており、該皮膜直下の部材表面から深さ方向に１〜１００μｍの領域に亘って前記硬質相が消失又は減少している硬質相貧化表面帯域が存在し、該硬質相貧化表面帯域に隣接して更に深さ方向に１〜２００μｍの領域に亘って硬質相富化中間帯域が存在している被覆超硬合金部材であり、該結合相中に希土類元素が含有され、かつ、希土類元素が存在する領域の酸素量が０〜５質量％であることを特徴とする被覆超硬合金部材である。上記の構成を採用することによって、耐熱、耐塑性変形と靭性の両特性が優れた被覆超硬合金部材を実現できることを見いだし、本発明に想到した。
また、本発明は、希土類元素用原料粉末として希土類金属とＣｏからなり、希土類元素量とＣｏ量のモル比が１：２〜１：８．５であり、しかも酸素含有量が０．０１〜１質量％である合金を用いることを特徴とする希土類元素含有超硬合金の製造方法である。上記の方法を採用することによって、元来酸化されやすい希土類元素を実質的に酸化させることなく結合相中に含有させることを実現できることを見いだし、本発明に想到した。 The present invention includes at least one of a binder phase mainly composed of an iron group metal and at least one carbide solid solution other than W selected from the periodic table 4a, 5a, and 6a group metals, a nitride solid solution, and a carbonitride solid solution. A hard coating is coated on the surface of the hard alloy member composed of one or more hard phases and the residual WC and inevitable impurities, and the hard coating is coated in a single layer or multiple layers, and in the depth direction from the surface of the member immediately below the coating. There exists a hard phase-depleted surface zone in which the hard phase has disappeared or decreased over a region of 1 to 100 μm, and further adjacent to the hard phase-poored surface zone in a region of 1 to 200 μm in the depth direction. It is a coated cemented carbide member in which a hard phase-enriched intermediate zone exists, and a rare earth element is contained in the binder phase, and the oxygen content in the region where the rare earth element is present is 0 to 5% by mass. It is a coated cemented carbide member characterized by being . By adopting the above-described configuration, it was found that a coated cemented carbide member excellent in both heat resistance, plastic deformation resistance and toughness can be realized, and the present invention has been conceived.
Further, the present invention comprises rare earth metal and Co as a rare earth element raw material powder, the molar ratio of the rare earth element amount to the Co amount is 1: 2 to 1: 8.5, and the oxygen content is 0.01 to It is a method for producing a rare earth element-containing cemented carbide characterized by using an alloy of 1% by mass. By adopting the above-mentioned method, it was found that the rare earth element that is originally easily oxidized can be contained in the binder phase without being substantially oxidized, and the present invention has been conceived.

本発明の被覆超硬合金部材は、該硬質相富化中間帯域内の硬質相を構成する金属成分含有量Iと該超硬合金部材内部の硬質相を構成する金属成分含有量Ｊの比率Ｉ／Ｊが１．０５〜１．３であることにより、硬質相富化中間帯域の耐摩耗性と耐熱、耐塑性変形性が高まるとともに、硬質相貧化表面帯域と硬質相富化中間帯域間の強度、及び硬質相富化中間帯域と部材内部間の強度が高まり、硬質相貧化表面帯域部が部材から脱落し難くなり、被覆超硬合金部材の靭性が高まり好ましい。本発明の被覆超硬合金部材は、該超硬合金部材内部における結合相の希土類元素含有量が、結合相を構成する鉄族金属含有量に対して、０．１〜１０質量％であることにより、結合相の耐塑性変形と耐摩耗性が高まり好ましい。該超硬合金部材内部における硬質相を構成する金属成分含有量Ｊが、質量％で１．５≦Ｊ≦１５％であることが、部材全体に高い耐摩耗性と耐欠損性とが得られて好ましい。該硬質相貧化表面帯域内の硬質相を構成する金属成分含有量をＫとし、該Ｊとの両者の比率Ｋ／Ｊが、０．１≦Ｋ／Ｊ≦０．７であり、該硬質相貧化表面帯域内の結合相を構成する金属成分含有量をＬとし、該超硬合金部材内部の結合相を構成する金属成分含有量をＭとしとした時、両者の比率Ｌ／Ｍが、１．１≦Ｌ／Ｍ≦１．８であることにより、耐欠損性と耐摩耗性の両者がバランス良くなり、好ましい。
また、結合相中に含有される希土類元素に少なくともＳｍ及び／又はＧｄが含まれていることにより、結合相中にＳｍやＧｄがより固溶し易くなり、耐熱性と強度とが高まり、好ましい。また、結合相にＣｒがＣｏの１〜１０質量％含有されていることにより、結合相自体の強度と耐熱性が高まり、好ましい。本発明は、また、硬質相中にＺｒを含有していることが、超硬合金全体の耐塑性変形性が高まり好ましく、ＺｒとともにＮｂ及び／またはＴａを含有していることにより、超硬合金部材の靭性が高まり更に好ましい。 The coated cemented carbide member of the present invention has a ratio I between the metal component content I constituting the hard phase in the hard phase-enriched intermediate zone and the metal component content J constituting the hard phase inside the cemented carbide member. When / J is 1.05 to 1.3, the wear resistance, heat resistance, and plastic deformation resistance of the hard phase enriched intermediate zone are increased, and between the hard phase poor surface zone and the hard phase enriched intermediate zone. And the strength between the hard phase-enriched intermediate zone and the inside of the member is increased, and the hard phase-depleted surface zone portion is less likely to fall out of the member, and the toughness of the coated cemented carbide member is preferably increased. In the coated cemented carbide member of the present invention, the rare earth element content of the binder phase in the cemented carbide member is 0.1 to 10% by mass with respect to the iron group metal content constituting the binder phase. This is preferable because the plastic deformation and wear resistance of the binder phase are increased. When the metal component content J constituting the hard phase in the cemented carbide member is 1.5 ≦ J ≦ 15% by mass%, high wear resistance and fracture resistance are obtained for the entire member. It is preferable. The metal component content constituting the hard phase in the hard phase-depleted surface zone is K, and the ratio K / J with J is 0.1 ≦ K / J ≦ 0.7, When the metal component content constituting the binder phase in the phase-poorized surface zone is L and the metal component content constituting the binder phase inside the cemented carbide member is M, the ratio L / M between them is 1.1 ≦ L / M ≦ 1.8 is preferable because both fracture resistance and wear resistance are well balanced.
Further, since at least Sm and / or Gd is contained in the rare earth element contained in the binder phase, Sm and Gd are more easily dissolved in the binder phase, and heat resistance and strength are increased, which is preferable. . Further, it is preferable that the binder phase contains Cr in an amount of 1 to 10% by mass of Co, which increases the strength and heat resistance of the binder phase itself. In the present invention, it is preferable that Zr is contained in the hard phase because the plastic deformation resistance of the entire cemented carbide is increased, and Nb and / or Ta is contained together with Zr. The toughness of the member is increased, which is more preferable.

本発明によって、結合相の耐熱、耐塑性変形性を格段に高めることにより、この特性の優れた被覆超硬合金部材を実現し、工具寿命の長い被覆超硬合金工具を提供することができた。また、元来酸化されやすい希土類元素を実質的に酸化させることなく結合相中に含有させる希土類元素含有超硬合金の製造方法を提供することができた。
本発明の被覆超硬合金部材及び／又は希土類元素含有超硬合金の製造方法を適用することによって、結合相の耐熱、耐塑性変形性が格段に高まり、特性の優れた被覆超硬合金部材が実現され、工具寿命の長い被覆超硬合金工具が実現できた。 According to the present invention, by significantly increasing the heat resistance and plastic deformation resistance of the binder phase, a coated cemented carbide member having excellent characteristics can be realized, and a coated cemented carbide tool having a long tool life can be provided. . Moreover, the manufacturing method of the rare earth element containing cemented carbide which can be contained in a binder phase without substantially oxidizing the rare earth element which is easy to oxidize originally was able to be provided.
By applying the method for producing a coated cemented carbide member and / or rare earth element-containing cemented carbide of the present invention, the heat resistance and plastic deformation resistance of the binder phase is remarkably increased, and a coated cemented carbide member having excellent characteristics is obtained. Realized and realized a coated cemented carbide tool with a long tool life.

結合相が少なくとも鉄族金属の１種又はそれ以上と希土類元素とにより形成されていることにより、結合相中に鉄族元素と原子半径が大きく異なる希土類元素（原子半径がＣｏの約１．２倍）と鉄族金属とが共存することになり、結合相の耐熱、耐塑性変形性と強度とが飛躍的に高まり、しかも、希土類元素が存在する領域の酸素量が０〜５質量％であることにより優れた靭性を有する被覆超硬合金部材が得られる。５質量％を越えて大きい酸素が希土類元素と一緒に検出されると、結合相の靭性や、結合相とＷＣ結晶粒間の強度が低下し、超硬合金の靭性が低下する欠点が現れる。
硬質相が周期律表４ａ、５ａ、６ａ族金属から選択されるＷ以外の少なくとも１種以上の炭化物固溶体、窒化物固溶体、炭窒化物固溶体の少なくとも１種以上より形成されていることにより、耐摩耗性の優れる硬質相が得られる。これにより、結合相を形成する鉄族金属と希土類元素とにより実質的に構成されている硬質相貧化表面帯域に特に優れた耐熱、耐塑性変形が得られるとともに、硬質相富化中間帯域に優れた耐摩耗性が実現でき、耐熱、耐塑性変形性と耐摩耗性の両者が優れる被覆超硬合金部材が実現できる。ここで、結合相形成金属が鉄族金属と希土類元素により形成されていることは、例えば、超硬合金部材の断面を研磨した後、硬質相貧化表面帯域の断面を走査電子顕微鏡（以下、ＳＥＭと記す。）により観察し、エネルギー分散型Ｘ線分析装置（以下、ＥＤＸと記す。）により面分析した時、ＷＣ結晶粒の回りに鉄族金属と希土類元素とがほぼ同じ分布状態で存在することからわかる。また、希土類元素が存在する領域の酸素量は、電子プローブ微小領域Ｘ線分析装置（以下、ＥＰＭＡと記す。）を用いて、超硬合金材の研磨面を５０ｋ倍で観察し希土類元素の面分布状況を測定した後、希土類元素が多く存在している約０．５μｍφの領域の酸素量を測定することにより求められる。硬質相がＺｒやＮｂ等の周期律表４ａ、５ａ、６ａ族金属から選択される少なくとも１種以上の炭化物固溶体、窒化物固溶体、炭窒化物固溶体の少なくとも１種以上を含有していること及び、その含有量は、超硬合金材の断面を研磨した後、硬質相部分をＳＥＭ−ＥＤＸにより分析することによりわかる。
該硬質相富化中間帯域内の硬質相を構成する金属成分含有量をＩとし、該超硬合金部材内部の硬質相を構成する金属成分含有量をＪとした時、両者の比率I／Ｊが１．０５≦I／Ｊ≦１．３であることが好ましい。こうすることにより、硬質相富化中間帯域の耐摩耗性と耐熱、耐塑性変形性が高まるとともに、硬質相貧化表面帯域〜部材内部間の強度が高まり、更に優れた切削耐久特性を有する被覆超硬合金工具が得られる。I／Ｊが１．０５未満では硬質相富化中間帯域の耐摩耗性と耐熱、耐塑性変形性が低下する。一方、I／Ｊが１．３を超えて大きくなると、硬質相富化中間帯域と硬質相貧化表面帯域との界面付近にクラックが出来やすくなり、超硬合金部材を用いた被覆超硬合金工具の切削耐久特性が低下する欠点が現れるため、好ましくない。 Since the binder phase is formed of at least one kind of iron group metal and a rare earth element, the rare earth element (atomic radius is approximately 1.2 of Co having an atomic radius greatly different from that of the iron group element in the binder phase). And the iron group metal coexist, the heat resistance, plastic deformation resistance and strength of the binder phase are dramatically increased, and the oxygen content in the region where the rare earth element is present is 0 to 5% by mass. By being, a coated cemented carbide member having excellent toughness can be obtained. When large oxygen exceeding 5% by mass is detected together with the rare earth element, the toughness of the binder phase and the strength between the binder phase and the WC crystal grains are lowered, and the defect that the toughness of the cemented carbide is lowered appears.
By forming the hard phase from at least one of solid carbide solutions other than W selected from periodic table 4a, 5a, and 6a group metals, nitride solid solution, carbonitride solid solution, A hard phase with excellent wear is obtained. As a result, particularly excellent heat and plastic deformation is obtained in the hard phase poor surface zone substantially composed of the iron group metal and the rare earth element forming the binder phase, and in the hard phase enriched intermediate zone. An excellent wear resistance can be realized, and a coated cemented carbide member excellent in both heat resistance, plastic deformation resistance and wear resistance can be realized. Here, the fact that the binder phase forming metal is formed of an iron group metal and a rare earth element is, for example, after polishing the cross section of the cemented carbide member, the cross section of the hard phase poor surface zone is a scanning electron microscope (hereinafter, Observed by SEM) and surface-analyzed by an energy dispersive X-ray analyzer (hereinafter referred to as EDX), iron group metals and rare earth elements exist in almost the same distribution around the WC crystal grains. From what you do. Further, the amount of oxygen in the region where the rare earth element is present is measured by observing the polished surface of the cemented carbide material at a magnification of 50 k using an electron probe micro region X-ray analyzer (hereinafter referred to as EPMA). After the distribution state is measured, it is obtained by measuring the amount of oxygen in a region of about 0.5 μmφ where a large amount of rare earth elements are present. The hard phase contains at least one or more kinds of carbide solid solution, nitride solid solution, carbonitride solid solution selected from Group 4a, 5a, and 6a metals of periodic table such as Zr and Nb; and The content can be understood by analyzing the hard phase portion by SEM-EDX after polishing the cross section of the cemented carbide material.
When the metal component content constituting the hard phase in the hard phase-enriched intermediate zone is I and the metal component content constituting the hard phase inside the cemented carbide member is J, the ratio of both I / J Is preferably 1.05 ≦ I / J ≦ 1.3. By doing so, the wear resistance, heat resistance, and plastic deformation resistance of the hard phase-enriched intermediate zone are increased, the strength between the hard phase poor surface zone and the inside of the member is increased, and the coating has excellent cutting durability characteristics. A cemented carbide tool is obtained. When I / J is less than 1.05, the wear resistance, heat resistance, and plastic deformation resistance of the hard phase enriched intermediate zone are lowered. On the other hand, when I / J exceeds 1.3, cracks are likely to occur near the interface between the hard phase-enriched intermediate zone and the hard phase-poor surface zone, and a coated cemented carbide using a cemented carbide member. Since the fault that the cutting durability characteristic of a tool falls appears, it is unpreferable.

本発明の結合相に少なくとも希土類元素が含有され、部材中央部における結合相中の希土類元素含有量が、Ｃｏの１〜１０質量％であることは、結合相の耐塑性変形と強度が高まり、優れた切削耐久特性を有する被覆超硬合金工具等が得られる。結合相の希土類元素含有量が、０．１質量％未満の時は結合相の耐塑性変形と強度が低下し、１０質量％を超えて大きいと部材全体の抗折力が低下し、工具寿命が短くなる欠点が現れるため、好ましくない。結合相形成金属中にＷが含有されていることが好ましく、結合相の耐熱、耐塑性変形が更に高まり、優れた特性を有する被覆超硬合金部材が実現できる。   The binder phase of the present invention contains at least a rare earth element, and the rare earth element content in the binder phase in the central part of the member is 1 to 10% by mass of Co, which increases the plastic deformation resistance and strength of the binder phase, A coated cemented carbide tool or the like having excellent cutting durability characteristics can be obtained. When the rare earth element content of the binder phase is less than 0.1% by mass, the plastic deformation resistance and strength of the binder phase decrease, and when it exceeds 10% by mass, the bending strength of the entire member decreases and the tool life is reduced. This is not preferable because of the shortcoming of shortening. It is preferable that W is contained in the binder phase forming metal, the heat resistance and plastic deformation of the binder phase are further increased, and a coated cemented carbide member having excellent characteristics can be realized.

本発明の該超硬合金部材内部における硬質相を構成する金属成分含有量Ｊが、質量％で１．５≦Ｊ≦１５であり、部材全体に高い耐摩耗性と耐欠損性とが得られ、優れた切削耐久特性が得られる。１．５質量％未満では部材全体の耐摩耗性と耐塑性変形性が低下し、１５質量％を超えて大きいと耐欠損性が低下する欠点が現れる。ここにいう硬質相とは全ての硬質相をいい、Ｗ以外の周期律表４ａ、５ａ、６ａ族金属から選択される少なくとも１種以上の炭化物固溶体、窒化物固溶体、炭窒化物固溶体の少なくとも１種以上を含有している硬質相以外も含めた硬質相の全てを言う。以下、単に硬質相という場合は、Ｗ以外の周期律表４ａ、５ａ、６ａ族金属から選択される少なくとも１種以上の炭化物固溶体、窒化物固溶体、炭窒化物固溶体の少なくとも１種以上を含有している硬質相以外も含めた全ての硬質相を言う。   The metal component content J constituting the hard phase in the cemented carbide member of the present invention is 1.5 ≦ J ≦ 15 in mass%, and high wear resistance and fracture resistance are obtained for the entire member. Excellent cutting durability characteristics can be obtained. If it is less than 1.5% by mass, the wear resistance and plastic deformation resistance of the entire member are lowered, and if it exceeds 15% by mass, the defect resistance is lowered. The term “hard phase” as used herein refers to all hard phases, and at least one of at least one carbide solid solution, nitride solid solution, and carbonitride solid solution selected from Group 4a, 5a, and 6a metals other than W in the periodic table. It refers to all of the hard phase including the hard phase containing more than seeds. Hereinafter, when simply referred to as a hard phase, it contains at least one or more kinds of carbide solid solutions, nitride solid solutions, carbonitride solid solutions selected from Group 4a, 5a, and 6a metals other than W. It refers to all hard phases including those other than the hard phase.

本発明のＫ／Ｊは、０．１≦Ｋ／Ｊ≦０．７であり、Ｌ／Ｍが、１．１≦Ｌ／Ｍ≦１．８であり、部材表面の耐欠損性が更に高まり、耐欠損性と耐摩耗性の両者がバランス良く優れ、切削耐久特性の優れた被覆超硬合金部材が得られる。Ｋ／Ｊの値が、０．１未満では部材表面の耐摩耗性が低下し、０．７を超えて大きいと部材表面の靭性が低下し、被覆超硬合金部材を用いた被覆超硬合金工具の切削耐久特性が低下する欠点が現れる。Ｌ／Ｍの値が、１．１未満であると部材表面の靭性が低下し、１．８を超えて大きいと部材表面の耐摩耗性が低下し、被覆超硬合金部材を用いた被覆超硬合金工具の切削耐久特性が低下する欠点が現れる。   K / J of the present invention is 0.1 ≦ K / J ≦ 0.7, L / M is 1.1 ≦ L / M ≦ 1.8, and the fracture resistance of the member surface is further increased. Thus, a coated cemented carbide member having excellent balance between fracture resistance and wear resistance and excellent cutting durability can be obtained. If the value of K / J is less than 0.1, the wear resistance of the member surface decreases, and if it exceeds 0.7, the toughness of the member surface decreases, and the coated cemented carbide using the coated cemented carbide member There is a drawback that the cutting durability characteristics of the tool are lowered. If the value of L / M is less than 1.1, the toughness of the member surface is reduced, and if it is more than 1.8, the wear resistance of the member surface is reduced, and the coated super-hard alloy using the coated cemented carbide member is used. The defect that the cutting durability characteristic of a hard alloy tool falls appears.

本発明の被覆超硬合金部材は、結合相にＣｒがＣｏの１〜１０質量％含有されていることが好ましい。これにより、結合相の耐熱性と耐塑性変形と耐摩耗性が高まり、優れた切削耐久特性を有する被覆超硬合金工具が得られる。結合相中のＣｒ含有量が、１質量％未満の時はＣｒ含有の効果が小さく、１０質量％を超えて大きいと部材全体の抗折力が低下し、工具寿命が短くなる欠点が現れる。
本発明の希土類元素用原料粉末として希土類元素とＣｏからなり、希土類とＣｏのモル比が１：２〜１：８．５であり、しかも酸素含有量が０．０１〜１質量％である合金を用いることを特徴とする希土類元素含有超硬合金の製造方法である。この方法により、元来酸化されやすい希土類元素を実質的に酸化させることなく結合相中に含有させるができ、結合相の耐塑性変形と強度とが飛躍的に高まり、優れた耐熱、耐久特性を有する被覆超硬合金部材が得られる。希土類とＣｏの比が１：２を越えて大きいと、本発明を用いて製作した超硬合金中で希土類元素の分布の均一性が低下し、超硬合金材の靭性が低下する欠点が現れ、１：８．５未満では、製造コストの高い希土類−Ｃｏ合金を多量に使用する必要が生じ、産業的価値が低下する欠点が現れる。希土類とＣｏのモル比は１：４から１：８．５であることが好ましい。１／４〜１／８．５の範囲であることにより、より均一な希土類−Ｃｏ合金を工業的に、より安価に製造出来る。また、合金中の酸素含有量が０．０１質量％未満では、本合金を更に高品質の非酸化雰囲気中で製造することが必要になるために、合金の製造方法が極端に高価になり産業的価値が低下し、１質量％を越えて大きいと結合相中や硬質相との界面に析出する希土類化合物が多くなり、靭性が低下する欠点が現れる。本発明の製造方法は、酸素含有量が０．０１〜０．２質量％である希土類元素−Ｃｏ合金を用いることが、更に優れた靭性を有する被覆超硬合金部材が得られ好ましい。本発明の高品質の非酸化雰囲気中で製造することが必要性になるために、このような希土類−Ｃｏ合金は、アーク溶解法やインダクションメルト鋳造法、ストリップキャスト法等で製造できるが、本発明はこれら合金の製造方法に関わらず有効である。 The coated cemented carbide member of the present invention preferably contains 1 to 10% by mass of Cr in the binder phase. Thereby, the heat resistance of the binder phase, the plastic deformation resistance, and the wear resistance are increased, and a coated cemented carbide tool having excellent cutting durability characteristics is obtained. When the Cr content in the binder phase is less than 1% by mass, the effect of the Cr content is small, and when it exceeds 10% by mass, the bending strength of the entire member is lowered and the tool life is shortened.
Alloys comprising rare earth elements and Co as rare earth element raw material powders of the present invention, wherein the rare earth to Co molar ratio is 1: 2 to 1: 8.5, and the oxygen content is 0.01 to 1 mass%. It is a manufacturing method of the rare earth element containing cemented carbide characterized by using this. By this method, a rare earth element that is easily oxidized can be contained in the binder phase without being substantially oxidized, and the plastic deformation and strength of the binder phase are drastically increased, resulting in excellent heat resistance and durability characteristics. A coated cemented carbide member having this is obtained. If the ratio of rare earth to Co is larger than 1: 2, the uniformity of the distribution of rare earth elements in the cemented carbide manufactured using the present invention is lowered, and the toughness of the cemented carbide material is reduced. If the ratio is less than 1: 8.5, it is necessary to use a large amount of a rare earth-Co alloy having a high production cost, resulting in a disadvantage that the industrial value is lowered. The molar ratio of rare earth to Co is preferably 1: 4 to 1: 8.5. By being in the range of 1/4 to 1 / 8.5, a more uniform rare earth-Co alloy can be produced industrially and at a lower cost. In addition, when the oxygen content in the alloy is less than 0.01% by mass, it is necessary to produce this alloy in a higher quality non-oxidizing atmosphere, which makes the alloy production method extremely expensive and industrial. When the target value is lowered and the amount exceeds 1% by mass, the rare earth compound precipitated in the binder phase or at the interface with the hard phase increases, resulting in a drawback that the toughness is lowered. In the production method of the present invention, it is preferable to use a rare earth element-Co alloy having an oxygen content of 0.01 to 0.2% by mass because a coated cemented carbide member having further excellent toughness can be obtained. Since it is necessary to manufacture in the high quality non-oxidizing atmosphere of the present invention, such rare earth-Co alloys can be manufactured by arc melting method, induction melt casting method, strip casting method, etc. The invention is effective regardless of the manufacturing method of these alloys.

本発明の被覆超硬合金部材の表面に被覆する皮膜としては周期律表４ａ、５ａ、６ａ族金属の炭素、窒素、酸素、硼素との化合物からなる皮膜や酸化アルミニウム膜、酸化ジルコニウム膜等の単層や多層膜を用いることができる。これらの皮膜を本発明の被覆超硬合金部材に被覆することにより、表面の耐摩耗性や耐酸化性、摺動性等を高めることが出来る。次に、本発明の被覆工具を実施例により具体的に説明するが、それら実施例により本発明が限定されるものではない。   Examples of the film to be coated on the surface of the coated cemented carbide member of the present invention include a film made of a compound of carbon, nitrogen, oxygen, boron of the periodic table 4a, 5a, and 6a group metals, an aluminum oxide film, a zirconium oxide film, etc. A single layer or a multilayer film can be used. By coating these coated films on the coated cemented carbide member of the present invention, the surface wear resistance, oxidation resistance, slidability and the like can be improved. Next, although the coated tool of this invention is concretely demonstrated by an Example, this invention is not limited by these Examples.

（実施例１）
希土類元素とＣｏの合金を作製するために、原料として９９．９％以上の純度を有するＣｏ金属１３２．４ｇとＳｍ金属６７．２ｇを秤量し、Ａｒ雰囲気中でアーク溶解を行いＳｍとＣｏのモル比が１：５であるＳｍＣｏ５合金を作製した。得られたＳｍＣｏ５合金を窒素雰囲気中で１〜２ｍｍの小粒に機械的に粉砕した後、次に記すＨＤプロセスを用いて約８０μｍ径のＳｍＣｏ５粗粉を得た。即ち、加圧可能なベッセルに、上記のＳｍＣｏ５合金を挿入し１５０μＰａの圧力まで真空度引きを行った。Ｈ２ガスによるフラッシングを２回行った後、５ＭＰａの水素圧で加圧し、ＳｍＣｏ５合金中に水素を吸蔵させ、水素吸蔵による温度上昇（約４０℃）を確認した。その後、脱水素させるために３７５μＰａまで真空引きを行い、脱水素に伴う温度低下（約２５℃）を確認し、ＳｍＣｏ５粗粉を得た。同様にして、ＧｄＣｏ５粗粉、ＹＣｏ５粗粉、ＰｒＣｏ５粗粉を作製した。作製したＳｍＣｏ５粗粉、ＧｄＣｏ５粗粉、ＹＣｏ５粗粉、ＰｒＣｏ５粗粉をガス分析装置で評価した結果、合金粉末中の酸素含有量はいずれも０．０５質量％であった。
このようにして得たＳｍＣｏ５粗粉、ＧｄＣｏ５粗粉、ＹＣｏ５粗粉、ＰｒＣｏ５粗粉とともに、原料粉末として以下のものを用いた。平均粒径が３．４μｍの中粒ＷＣ粉末、同６．３μｍの粗粒ＷＣ粉末。平均粒径が２．５μｍのＺｒ（ＣＮ）粉末。質量比は、ＺｒＣ／ＺｒＮが５０／５０。平均粒径が１．５μｍの（ＴａＮｂ）Ｃ粉末。質量比は、ＴａＣ／ＮｂＣが９０／１０。平均粒径が２．８μｍのＴｉ（ＣＮ）粉末。質量比は、ＴｉＣ／ＴｉＮが５０／５０。平均粒径が１．２μｍのＣｏ粉末。これら原料粉末を所定量に配合し、ボールミルで７２時間湿式混合して乾燥し、所定形状の圧粉体にプレス成形し、１４５０℃で１時間保持することにより焼結した。このようにして作製した焼結体に仕上げ加工及びホーニング加工を施すことにより、いずれもＩＳＯ規格ＣＮＭＧ１２０４０８のインサート形状をもった超硬合金部材を製造し、表１にまとめて記した。 Example 1
In order to produce an alloy of rare earth elements and Co, 132.4 g of Co metal having a purity of 99.9% or more and 67.2 g of Sm metal are weighed as raw materials, and arc melting is performed in an Ar atmosphere to perform the melting of Sm and Co. An SmCo5 alloy having a molar ratio of 1: 5 was produced. The obtained SmCo5 alloy was mechanically pulverized into small particles of 1 to 2 mm in a nitrogen atmosphere, and then an SmCo5 coarse powder having a diameter of about 80 μm was obtained using the HD process described below. That is, the above SmCo5 alloy was inserted into a pressurizable vessel, and the degree of vacuum was reduced to a pressure of 150 μPa. After flushing with H2 gas twice, pressurization was performed at a hydrogen pressure of 5 MPa to occlude hydrogen in the SmCo5 alloy, and an increase in temperature due to occlusion of hydrogen (about 40 ° C.) was confirmed. Then, in order to dehydrogenate, vacuuming was performed to 375 μPa, and a temperature drop (about 25 ° C.) accompanying dehydrogenation was confirmed to obtain SmCo5 coarse powder. Similarly, GdCo5 coarse powder, YCo5 coarse powder, and PrCo5 coarse powder were produced. As a result of evaluating the produced SmCo5 coarse powder, GdCo5 coarse powder, YCo5 coarse powder, and PrCo5 coarse powder with a gas analyzer, the oxygen content in the alloy powder was 0.05% by mass.
Along with the SmCo5 coarse powder, GdCo5 coarse powder, YCo5 coarse powder, and PrCo5 coarse powder thus obtained, the following were used as raw material powders. Medium WC powder having an average particle size of 3.4 μm and coarse WC powder having the same particle size of 6.3 μm. Zr (CN) powder having an average particle size of 2.5 μm. As for mass ratio, ZrC / ZrN is 50/50. (TaNb) C powder having an average particle size of 1.5 μm. As for mass ratio, TaC / NbC is 90/10. Ti (CN) powder having an average particle size of 2.8 μm. The mass ratio is 50/50 for TiC / TiN. Co powder having an average particle size of 1.2 μm. These raw material powders were blended in a predetermined amount, wet mixed by a ball mill for 72 hours, dried, pressed into a green compact having a predetermined shape, and sintered by holding at 1450 ° C. for 1 hour. A cemented carbide member having an insert shape of ISO standard CNMG120408 was manufactured by subjecting the sintered body thus produced to finish processing and honing processing.

本発明例１６の配合組成は、Ｃｏ：５．７６質量％、ＳｍＣｏ５：０．３６質量％、Ｚｒ（ＣＮ）：１．５質量％、（ＴａＮｂ）Ｃ：１質量％、残ＷＣ及び不可避不純物である。焼結は、５００〜１４００℃まで真空とし、１４００〜１４５０℃までは１．３ｋＰａの窒素雰囲気に保った後、１４５０℃の最後の３０分間を再び真空に保った。また、これを基準にして、本発明例１〜５は窒素雰囲気の圧力を変化させることにより作製した。本発明例６〜１１はＣｏ全量を固定して、ＳｍＣｏ５合金の使用量のみを変化させることにより作製した。本発明例１２〜２１はＣｏとＳｍＣｏ５合金量、及びＺｒ（ＣＮ）／（ＴａＮｂ）Ｃの比率を変えることなく、Ｚｒ（ＣＮ）と（ＴａＮｂ）Ｃの配合合計量を変化させる事により作製した。本発明例２２〜２７はＺｒ／（Ｔａ＋Ｎｂ）の比率を変化させるとともに、真空雰囲気での保持時間を変化させることにより作製した。本発明例２８〜３０は本発明例１６と同じ条件で、希土類元素としてＳｍに換えて、Ｇｄ、Ｙ、Ｐｒを結合相中にＣｏの２質量％含有させることにより作製した。本発明例３１は本発明例１６と同じ条件と組成比で、（ＴａＮｂ）Ｃ粉末を加えることなく作製した。本発明例３２は本発明例１６と同じ条件で、Ｚｒ（ＣＮ）に換えてＴｉ（ＣＮ）をＺｒ（ＣＮ）と同質量％含有させることにより作製した。
また、比較の目的で、原料粉末として、平均粒径が３．４μｍの中粒ＷＣ粉末、同６．３μｍの粗粒ＷＣ粉末、同２μｍのＺｒＣＮ粉末、同１．５μｍの（ＴａＮｂ）Ｃ粉末、及び同１．２μｍのＣｏ粉末を用意し、上記本発明例と同じ製造工程でプレス成形体を形成し、１４５０℃で１時間保持し焼結することにより、上記と同一形状のインサート形状をもち、本発明例１６或いは本発明例２１とほぼ同じ組成で希土類元素を含有していない比較例３３、３４を作製した。このときの焼成条件は、昇温パターンは上記と同じで、焼結炉内雰囲気を５００〜１４００℃までは２．６６ｋＰａの窒素雰囲気にし、１４００℃以降は真空雰囲気に保つようにした。 The composition of Invention Example 16 is Co: 5.76% by mass, SmCo5: 0.36% by mass, Zr (CN): 1.5% by mass, (TaNb) C: 1% by mass, residual WC and inevitable impurities It is. Sintering was evacuated to 500 to 1400 ° C., maintained in a nitrogen atmosphere of 1.3 kPa up to 1400 to 1450 ° C., and then kept in vacuum again for the last 30 minutes at 1450 ° C. Based on this, Examples 1 to 5 of the present invention were produced by changing the pressure of the nitrogen atmosphere. Invention Examples 6 to 11 were prepared by fixing the total amount of Co and changing only the amount of SmCo5 alloy used. Invention Examples 12 to 21 were prepared by changing the total amount of Zr (CN) and (TaNb) C without changing the amount of Co and SmCo5 alloy and the ratio of Zr (CN) / (TaNb) C. . Invention Examples 22 to 27 were produced by changing the ratio of Zr / (Ta + Nb) and changing the holding time in a vacuum atmosphere. Invention Examples 28 to 30 were produced under the same conditions as in Invention Example 16, except that 2% by mass of Co was contained in the binder phase instead of Sm as the rare earth element. Invention Example 31 was produced under the same conditions and composition ratio as Invention Example 16 without adding (TaNb) C powder. Invention Example 32 was produced under the same conditions as in Invention Example 16, except that Ti (CN) was contained in the same mass% as Zr (CN) instead of Zr (CN).
For comparison purposes, as raw material powder, medium grain WC powder with an average particle diameter of 3.4 μm, coarse WC powder with 6.3 μm, ZrCN powder with 2 μm, (TaNb) C powder with 1.5 μm The same 1.2 μm Co powder was prepared, and a press-molded body was formed in the same production process as the above-described example of the present invention, and held at 1450 ° C. for 1 hour to sinter. Thus, Comparative Examples 33 and 34 having almost the same composition as Invention Example 16 or Invention Example 21 and containing no rare earth element were produced. The firing conditions at this time were the same as those described above, and the atmosphere in the sintering furnace was a nitrogen atmosphere of 2.66 kPa from 500 to 1400 ° C., and a vacuum atmosphere was maintained after 1400 ° C.

上記のように、本発明例１〜３２と比較例３３、３４の超硬合金製基体をＪＩＳ規格ＣＮＭＧ１２０４０８形状に加工した後、化学蒸着装置内にセットし、Ｈ２キヤリヤーガスとＴｉＣｌ４ガスとＮ２ガスとを原料ガスに用いて０．５μｍ厚さのＴｉＮ膜を９００℃で形成し、Ｈ２キャリヤーガスとＴｉＣｌ４ガス、Ｎ２ガス、ＣＨ３ＣＮガスを原料ガスに用いて厚さ６μｍのＴｉ（ＣＮ）膜を８９０℃で形成した。そして、１０００℃でＨ２キヤリヤーガスとＴｉＣｌ４ガス、ＣＨ４ガスとを原料ガスに用いてＴｉＣ膜を１５分間成膜し、そのまま連続して本構成ガスにＣＯ２ガスとＣＯガスとを追加し１５分間成膜することのよりＴｉ（ＣＯ）膜を形成した。そして、Ｈ２キャリヤーガス、ＡｌＣｌ３ガス、ＣＯ２ガスを原料ガスに用いて厚さ４μｍのα型Ａｌ２Ｏ３膜を１０２０℃で形成し、更に、Ｈ２キヤリヤーガスとＴｉＣｌ４ガスとＮ２ガスとを原料ガスに用いて０．５μｍ厚さのＴｉＮ膜を１０１０℃で形成し、その後室温まで冷却することにより本発明例１〜３２と比較例３３、３４の被覆超硬合金工具を作製した。   As described above, after the cemented carbide substrates of Invention Examples 1 to 32 and Comparative Examples 33 and 34 were processed into a JIS standard CNMG120408 shape, they were set in a chemical vapor deposition apparatus, and H2 carrier gas, TiCl4 gas, N2 gas, Is used as a source gas to form a 0.5 μm thick TiN film at 900 ° C., and a H 2 carrier gas, TiCl 4 gas, N 2 gas, and CH 3 CN gas are used as source gases to form a 6 μm thick Ti (CN) film 890. Formed at ° C. Then, at 1000 ° C., a TiC film is formed for 15 minutes using H2 carrier gas, TiCl4 gas, and CH4 gas as source gases, and CO2 gas and CO gas are continuously added to this constituent gas for 15 minutes. As a result, a Ti (CO) film was formed. Then, an α-type Al 2 O 3 film having a thickness of 4 μm is formed at 1020 ° C. using H 2 carrier gas, AlCl 3 gas, and CO 2 gas as raw material gases, and further, H 2 carrier gas, TiCl 4 gas, and N 2 gas are used as raw material gases. A TiN film having a thickness of 0.5 μm was formed at 1010 ° C., and then cooled to room temperature, whereby coated cemented carbide tools of Invention Examples 1 to 32 and Comparative Examples 33 and 34 were produced.

これら試料の断面を研磨し、光学顕微鏡で硬質相の分布状況を観察し、ＳＥＭ（日立製作所製、Ｓ−４２００）−ＥＤＸ（堀場製作所製Ｓ−７９２Ｘ１）で分析した結果、本発明例１〜２７は部材の結合相がＣｏとＳｍとからなっており、硬質相の５０％以上がＺｒとともにＴａ及び／又はＮｂを含有しており、部材表面に、硬質相が消失又は減少し、ＣｏとＳｍとからなる結合相が主である硬質相貧化表面帯域が深さ方向に１〜１００μｍの領域に亘って存在し、これに隣接して、更に深さ方向に１〜２００μｍの領域に亘って、硬質相富化中間帯域が存在し、I／Ｊ≧１である硬質相富化中間帯域が存在していた。また、本発明例２８、２９、３０はＳｍの代わりに、Ｇｄ、Ｙ、Ｐｒが結合相中に含有されており、また、本発明例３１は部材の結合相がＣｏとＳｍとからなっているが、硬質相中にＮｂとＴａとが含有されていなかった。本発明例３２は部材の結合相がＣｏとＳｍとからなっているが、硬質相中にＺｒが含有されておらず、替わりにＴｉが含有されていた。本発明例２８〜３２の硬質相貧化表面帯域や硬質相富化中間帯域、I／Ｊは本発明例１〜２７と同様に形成されていた。本発明例の超硬合金部材の研磨面をＳＥＭで観察したとき、ＷＣ粒子は灰色に、硬質相はＷＣ粒子よりも黒い粒子として観察され、結合相はこれらの粒子間を埋める形で観察された。本発明例１６の超硬合金部材内部の研磨済み断面を２００μｍ幅に亘ってＣｏとＳｍ、及びＺｒとＮｂの分布状況をそれぞれ同時に線分析した結果を図１、２に示す。これらは、島津製作所製、ＥＰＭ−８１０型のＥＰＭＡ装置を用い、電圧１５ｋＶ、電流５０ｎＡで直径約１μｍの電子線により、１μｍステップごとに、各ポイント当たり１秒間計測することにより測定した。なお、図１、２は、縦軸の０点とカウント数の取り方を変えることにより、ＣｏとＳｍ及びＺｒとＮｂの間で、それぞれの分布パターンを判別し易くしてある。図１より、ＣｏとＳｍとが同一パターンで分布しており、両者がともに結合相中に含有されていることがわかる。また、図２より、ＺｒとＮｂとが同一パターンで分布しており、両者が主に同一硬質相内に含有されていることがわかる。これに対して、比較例３３、３４は硬質相貧化表面帯域と硬質相富化中間帯域とが存在しているものの、結合相中にＳｍ等の希土類元素が検出されなかった。
表１に、これら試料のＣｏ中に含有されている希土類元素の種類と対Ｃｏ比で分析した含有量とをまとめて記した。その分析方法は、各試料を微細に粉砕した粉をクエン酸アンモニウム５０ｇ／Ｌと塩化ナトリウム５ｇ／Ｌの混合液を用いて電気分解することによりＣｏを選択的に溶解し、これに少量の硝酸を加えて、Ｃｏ中に溶解している希土類元素成分をイオン化して、ＩＣＰ（誘導結合高周波プラズマ分光）分析することにより、結合相を構成しているＣｏ中に含有されている希土類元素の量を定量的に求めたものである。
また、本発明例１〜３２の超硬合金部材の組織を、日本電子株式会社製、ＪＸＡ−８２００型のＥＰＭＡ装置により５０ｋ倍で観察し希土類元素のマッピングをとった後、希土類元素が多く存在している約０．５μｍφの領域の酸素量を加速電圧１０ｋＶで測定した結果、酸素含有量は０〜０．２質量％であった。 As a result of polishing the cross section of these samples, observing the distribution of the hard phase with an optical microscope, and analyzing with SEM (Hitachi, S-4200) -EDX (Horiba, S-792X1), Examples 1 to 27, the binder phase of the member consists of Co and Sm, 50% or more of the hard phase contains Ta and / or Nb together with Zr, the hard phase disappears or decreases on the surface of the member, Co and A hard phase-depleted surface zone mainly composed of a binder phase composed of Sm exists over a region of 1 to 100 μm in the depth direction, and further adjacent to this, a region of 1 to 200 μm in the depth direction. Thus, there was a hard phase enriched intermediate zone and a hard phase enriched intermediate zone with I / J ≧ 1. Inventive examples 28, 29, and 30 contain Gd, Y, and Pr in the binder phase instead of Sm, and in inventive example 31, the binder phase of the member consists of Co and Sm. However, Nb and Ta were not contained in the hard phase. In Invention Example 32, the binder phase of the member was composed of Co and Sm, but Zr was not contained in the hard phase, and Ti was contained instead. The hard phase poor surface zone, the hard phase enriched intermediate zone, and I / J of Invention Examples 28 to 32 were formed in the same manner as in Invention Examples 1 to 27. When the polished surface of the cemented carbide member of the present invention is observed by SEM, the WC particles are observed as gray, the hard phase is observed as black particles than the WC particles, and the binder phase is observed in a form of filling between these particles. It was. FIGS. 1 and 2 show the results of simultaneous line analysis of Co and Sm, and Zr and Nb, respectively, over a polished cross section inside the cemented carbide member of Inventive Example 16 over a width of 200 μm. These were measured by using an EPM-810 type EPMA apparatus manufactured by Shimadzu Corporation and measuring for 1 second at each step of 1 μm with an electron beam having a voltage of 15 kV and a current of 50 nA and a diameter of about 1 μm. In FIGS. 1 and 2, the distribution pattern between Co and Sm and Zr and Nb is easily discriminated by changing the 0 point on the vertical axis and the way of counting. As can be seen from FIG. 1, Co and Sm are distributed in the same pattern, and both are contained in the binder phase. Moreover, FIG. 2 shows that Zr and Nb are distributed in the same pattern, and both are mainly contained in the same hard phase. In contrast, in Comparative Examples 33 and 34, although a hard phase-poor surface zone and a hard phase-enriched intermediate zone existed, rare earth elements such as Sm were not detected in the binder phase.
Table 1 summarizes the types of rare earth elements contained in Co in these samples and the contents analyzed by the Co ratio. In the analysis method, Co is selectively dissolved by electrolyzing a finely pulverized powder of each sample using a mixed solution of ammonium citrate 50 g / L and sodium chloride 5 g / L, and a small amount of nitric acid is dissolved therein. The amount of rare earth elements contained in Co constituting the bonded phase is obtained by ionizing the rare earth elements dissolved in Co and analyzing by ICP (Inductively Coupled High Frequency Plasma Spectroscopy). Is obtained quantitatively.
In addition, the microstructure of the cemented carbide members of Invention Examples 1 to 32 was observed with a JXA-8200 type EPMA apparatus manufactured by JEOL Ltd. at a magnification of 50 k, and after mapping of rare earth elements, there were many rare earth elements. As a result of measuring the amount of oxygen in the approximately 0.5 μmφ region at an acceleration voltage of 10 kV, the oxygen content was 0 to 0.2 mass%.

本発明例１〜３２と比較例３３、３４との差異を評価するため、連続切削寿命特性を以下の切削条件で評価した。各切削時間における摩耗量を倍率５０倍の工具顕微鏡で観察し、平均逃げ面摩耗量が０．４ｍｍ、クレーター摩耗が０．０５ｍｍのどちらかに達した時間を連続切削寿命時間と判断した。
（加工条件１）
被削材 ：Ｓ５３Ｃ
切削速度：３００ｍ／分
送り ：０．２５ｍｍ／ｒｅｖ
切り込み：１．５ｍｍ
切削油 ：使用せず、乾式切削
また、同一ロットの切削工具各５個を以下の条件で断続切削し、欠損に至るまでの断続切削可能回数を評価した。刃先先端の欠け状況は倍率５０倍の実体顕微鏡で観察した。
（加工条件２）
被削材 ：Ｓ５３Ｃ、４溝入材（ＨＳ３８）
切削条件：２００ｍ／ｍｉｎ
送り ：０.２５ｍｍ／ｒｅｖ
切り込み：１．５ｍｍ
切削液 ：使用せず、乾式切削
上記の条件で切削評価した結果を表１中に併記する。 In order to evaluate the difference between Invention Examples 1 to 32 and Comparative Examples 33 and 34, the continuous cutting life characteristics were evaluated under the following cutting conditions. The amount of wear at each cutting time was observed with a tool microscope having a magnification of 50 times, and the time when the average flank wear amount reached 0.4 mm and the crater wear reached 0.05 mm was determined as the continuous cutting life time.
(Processing condition 1)
Work material: S53C
Cutting speed: 300 m / min Feed: 0.25 mm / rev
Cutting depth: 1.5mm
Cutting oil: Not used, dry cutting In addition, each of 5 cutting tools of the same lot was intermittently cut under the following conditions, and the number of times of intermittent cutting until failure was evaluated. The chipping state of the blade tip was observed with a stereomicroscope with a magnification of 50 times.
(Processing condition 2)
Work material: S53C, 4-grooved material (HS38)
Cutting conditions: 200 m / min
Feed: 0.25mm / rev
Cutting depth: 1.5mm
Cutting fluid: Not used, dry cutting The results of cutting evaluation under the above conditions are also shown in Table 1.

表１において、略同じ組成を持つ本発明例１６と比較例３３とを比較する。比較例３３は結合相中に希土類が含有されておらず、連続切削寿命が１４分、断続切削寿命が２３００回であるのに対して、本発明例１６は、結合相がＣｏとＳｍから成っているため、連続切削寿命が４０分と２．８倍以上長く、しかも断続切削寿命も３７００回と１．６倍以上長い。また、硬質相含有量Ｊが同じ６質量％である本発明例１〜１１と１６、及び２２〜３２と比較例３３とを比較すると、結合相中に希土類元素を含有している本発明例１〜１１と１６、及び２２〜３２は希土類元素を含有していない比較例３３よりも連続切削寿命が２倍以上長く、断続切削寿命も１．６倍以上長い。また、硬質相含有量Ｊが同じ１７質量％である本発明例２１と比較例３４とを比較したとき、比較例３４は連続切削寿命が１６分、断続切削寿命が９００回であるのに対して、本発明例２１は連続切削寿命が４６分と２．８倍以上長く、断続切削寿命も１４００回と１．５倍以上長い。本発明例は、格段に優れた工具特性を有していることがわかる。
次に、本発明例１〜５内を比較する。まず、本発明例１と２を比較すると、本発明例２はＩ／Ｊが１．０５であるのに対し、本発明例１はＩ／Ｊが１．０２であるので、両者共同じ断続切削寿命でありながら、本発明例２の方は本発明例１よりも連続切削寿命が１．３倍優れている。本発明例４と５を比較すると、本発明例４はＩ／Ｊが１．３であるのに対し、本発明例５はＩ／Ｊが１．４であるので、両者共にほぼ同じ連続切削寿命でありながら、本発明例４の方は本発明例５よりも断続切削寿命が１．３倍優れている。即ち、本発明例はI／Ｊ≧１であり、更にI／Ｊは、１．０５≦I／Ｊ≦１．３であることが好ましい。
本発明例６〜１１内を比較する。本発明例７は部材内部における希土類元素／Ｃｏ比が０．１質量％であるのに対し、本発明例６は希土類元素／Ｃｏが０．０５質量％である。本発明例７は本発明例６に比べて断続切削寿命と連続切削寿命の両者が１．３倍優れている。また、本発明例１０は希土類元素／Ｃｏが１０質量％であるのに対し、本発明例１１は、希土類元素／Ｃｏが１２質量％である。本発明例１０は、本発明例１１に比べて同じ連続切削寿命ありながら断続切削寿命が１．３倍優れている。即ち、本発明例の中でも超硬合金部材内部における結合相の希土類元素含有量が、結合相を構成する鉄族金属含有量に対して、０．１〜１０質量％であることが好ましい。
本発明例１２〜２１内を比較する。本発明例１３はＪが１．５質量％であるのに対し、本発明例１２はＪが１質量％である。本発明例１３は本発明例１２に比べて同じ断続切削寿命でありながら連続切削寿命が１．３倍優れている。本発明例２０はＪが１５質量％であるのに対し、本発明例２１はＪが１７質量％である。本発明例２０は本発明例２１に比べてほぼ同じ連続切削寿命でありながら断続切削寿命が１．６倍優れていることがわかる。即ち、本発明例の中でも、１．５≦Ｊ≦１５であることが好ましい。
本発明例２２〜２７内を比較する。まず、本発明例２２と２３を比較すると、本発明例２３はＫ／Ｊが０．１、Ｌ／Ｍが１．８であるのに対し、本発明例２２はＫ／Ｊが０、Ｌ／Ｍが１．９であるので、両者共同じ断続切削寿命でありながら、本発明例２３の方は本発明例２２よりも連続切削寿命が１．３倍優れている。本発明例２６と２７を比較すると、本発明例２６はＫ／Ｊが０．７、Ｌ／Ｍが１．１であるのに対し、本発明例２７はＫ／Ｊが０．９、Ｌ／Ｍが１．０５であるので、両者共同じ連続切削寿命でありながら、本発明例２６の方は本発明例２７よりも断続切削寿命が１．３倍優れている。即ち、本発明例の中でも０．１≦Ｋ／Ｊ≦０．７、１．１≦Ｌ／Ｍ≦１．８であることが好ましい。
本発明例１６と本発明例２８〜３０内を比較する。本発明例２９、３０は結合相内に希土類元素としてＹやＰｒを２質量％含有しているのに対して、本発明例１６と２８とはそれぞれＳｍ又はＧｄを２質量％含有しており、本発明例１６と２８とは本発明例２９や３０に比べて連続切削寿命が１．３倍以上優れている。即ち、本発明例の中でも超硬合金部材の結合相中に含有される希土類元素はＳｍ及び／又はＧｄであることが好ましい。
本発明例１６と本発明例３１とを比較する。本発明例１６はＺｒとともにＮｂとＴａを含有しているのに対して、本発明例３１は硬質相内にＮｂもＴａも含有していない。本発明例１６は本発明例３１に比べて連続切削寿命が１．３倍以上優れている。即ち、本発明例の中でも超硬合金部材の硬質相内にＺｒとともにＮｂまたは／及びＴａを含有していることが好ましい。
本発明例１６と本発明例３２とを比較する。本発明例１６はＺｒを含有しているのに対して、本発明例３２は硬質相内にＺｒを含有していない。本発明例１６は本発明例３２に比べて連続切削寿命が１．４倍以上優れている。即ち、本発明例の中でも超硬合金部材の硬質相内にＺｒを含有していることが好ましい。 In Table 1, Invention Example 16 and Comparative Example 33 having substantially the same composition are compared. Comparative Example 33 contains no rare earth in the binder phase, has a continuous cutting life of 14 minutes, and an interrupted cutting life of 2300 times, whereas Example 16 of the invention has a binder phase composed of Co and Sm. Therefore, the continuous cutting life is 40 minutes, which is 2.8 times longer, and the intermittent cutting life is 3,700 times, which is 1.6 times longer. Further, when Examples 1 to 11 and 16 of the present invention having the same hard phase content J of 6% by mass, and Comparative Example 33 of 22 to 32 are compared, Examples of the present invention containing rare earth elements in the binder phase. 1 to 11, 16 and 22 to 32 have a continuous cutting life that is twice or more longer than that of Comparative Example 33 that does not contain a rare earth element, and an intermittent cutting life that is 1.6 times or more longer. Further, when the inventive example 21 and the comparative example 34 having the same hard phase content J of 17% by mass are compared, the comparative example 34 has a continuous cutting life of 16 minutes and an intermittent cutting life of 900 times. The inventive example 21 has a continuous cutting life of 46 minutes, which is 2.8 times longer, and an intermittent cutting life of 1,400 times, which is 1.5 times longer. It turns out that the example of the present invention has remarkably excellent tool characteristics.
Next, Examples 1 to 5 of the present invention will be compared. First, when Example 1 and 2 of the present invention are compared with each other, Example 2 of the present invention has an I / J of 1.05, whereas Example 1 of the present invention has an I / J of 1.02. Although it is a cutting life, the example 2 of this invention has the continuous cutting life 1.3 times superior to the example 1 of this invention. Comparing the inventive examples 4 and 5, the inventive example 4 has an I / J of 1.3, whereas the inventive example 5 has an I / J of 1.4. In spite of the longevity, Invention Example 4 is 1.3 times better in interrupted cutting life than Invention Example 5. That is, in the example of the present invention, I / J ≧ 1, and I / J is preferably 1.05 ≦ I / J ≦ 1.3.
The invention examples 6 to 11 are compared. Inventive Example 7 has a rare earth element / Co ratio inside the member of 0.1% by mass, while Inventive Example 6 has a rare earth element / Co of 0.05% by mass. Invention Example 7 is 1.3 times better in both interrupted cutting life and continuous cutting life than Invention Example 6. Inventive Example 10 has 10% by mass of rare earth element / Co, while Inventive Example 11 has 12% by mass of rare earth element / Co. Inventive Example 10 is 1.3 times better in interrupted cutting life than Inventive Example 11 with the same continuous cutting life. That is, among the examples of the present invention, the rare earth element content of the binder phase inside the cemented carbide member is preferably 0.1 to 10% by mass with respect to the iron group metal content constituting the binder phase.
The invention examples 12 to 21 are compared. Invention Example 13 has J of 1.5% by mass, while Invention Example 12 has J of 1% by mass. Invention Example 13 is 1.3 times better in continuous cutting life than Example 12 in spite of the same intermittent cutting life. In the inventive example 20, J is 15% by mass, while in the inventive example 21, J is 17% by mass. It can be seen that Inventive Example 20 has an interrupted cutting life that is 1.6 times better than Inventive Example 21, although it has substantially the same continuous cutting life. That is, it is preferable that 1.5 ≦ J ≦ 15 among the examples of the present invention.
The invention examples 22 to 27 are compared. First, the inventive examples 22 and 23 are compared. In the inventive example 23, K / J is 0.1 and L / M is 1.8, whereas in the inventive example 22, K / J is 0, L Since / M is 1.9, the inventive example 23 is 1.3 times better in continuous cutting life than the inventive example 22, while both have the same intermittent cutting life. Comparing the inventive examples 26 and 27, the inventive example 26 has a K / J of 0.7 and an L / M of 1.1, whereas the inventive example 27 has a K / J of 0.9 and an L / M. Since / M is 1.05, both of them have the same continuous cutting life, but the inventive example 26 has 1.3 times better interrupted cutting life than the inventive example 27. That is, it is preferable that 0.1 ≦ K / J ≦ 0.7 and 1.1 ≦ L / M ≦ 1.8 among the examples of the present invention.
The present invention example 16 is compared with the present invention examples 28-30. Inventive Examples 29 and 30 contain 2% by mass of Y or Pr as rare earth elements in the binder phase, while Inventive Examples 16 and 28 each contain 2% by mass of Sm or Gd. Inventive Examples 16 and 28 have a continuous cutting life 1.3 times or more superior to Inventive Examples 29 and 30. That is, among the examples of the present invention, the rare earth element contained in the binder phase of the cemented carbide member is preferably Sm and / or Gd.
Inventive Example 16 and Inventive Example 31 are compared. Invention Example 16 contains Nb and Ta together with Zr, while Invention Example 31 contains neither Nb nor Ta in the hard phase. Invention Example 16 has a continuous cutting life 1.3 times or more superior to Invention Example 31. That is, among the examples of the present invention, it is preferable that Nb or / and Ta are contained together with Zr in the hard phase of the cemented carbide member.
Inventive Example 16 and Inventive Example 32 are compared. Invention Example 16 contains Zr, while Invention Example 32 does not contain Zr in the hard phase. Invention Example 16 has a continuous cutting life of 1.4 times or more superior to Invention Example 32. That is, among the examples of the present invention, it is preferable that Zr is contained in the hard phase of the cemented carbide member.

（実施例２）
希土類元素とともにＣｒを結合相中に含有させた場合の効果を評価するために、実施例１と同じＳｍＣｏ５粗粉、中粒ＷＣ粉末、粗粒ＷＣ粉末、Ｚｒ（ＣＮ）粉末、（ＴａＮｂ）Ｃ粉末、Ｃｏ粉末、及び、新たに、平均粒径が２．０μｍのＣｒ3Ｃ2粉末を用いて、実施例１の本発明例１６と同じ組成比ながらＣｏ中に含有されるＣｒ量のみが異なる本発明例３５〜４１を実施例１と同じ製造条件で同じ形状をもった超硬合金部材に製造し、実施例１と同じ条件で皮膜を形成することにより作製した。また、比較のために、結合相中にＣｒが含有されているものの希土類元素が含有されていない比較例４２を実施例１と同じ条件で作製した。
これら本発明例３５〜４１と比較例４２とを、実施例１と同じ条件で超硬合金製部材の組織と切削特性を評価した。その結果、本発明例３５〜４１の結合相中には、Ｓｍが２質量％、Ｃｒがそれぞれ０．５、１、２、５、９、１０、１１質量％含有されているのに対して、比較例４２は結合相中にＣｒがＣｏの５質量％含有されていたが、Ｓｍ等の希土類元素は含有されていなかった。また、本発明例３５〜４１と比較例４２はともに、希土類元素が多く存在している約０．５μｍφの領域の酸素量が０〜０．２質量％であり、Ｊが６質量％、Ｋ／Ｊが０．３、Ｌ／Ｍが１．４、Ｉ／Ｊが１．１であった。これらの本発明例と比較例の評価結果を表２にまとめて記した。 (Example 2)
In order to evaluate the effect when Cr is contained in the binder phase together with rare earth elements, the same SmCo5 coarse powder, medium WC powder, coarse WC powder, Zr (CN) powder, (TaNb) C as in Example 1 are used. Using the powder, Co powder, and a new Cr3C2 powder having an average particle size of 2.0 μm, the present invention differs only in the amount of Cr contained in Co with the same composition ratio as that of Invention Example 16 of Example 1. Examples 35 to 41 were manufactured by manufacturing a cemented carbide member having the same shape under the same manufacturing conditions as in Example 1 and forming a film under the same conditions as in Example 1. For comparison, Comparative Example 42 containing Cr in the binder phase but containing no rare earth element was produced under the same conditions as in Example 1.
The inventive examples 35-41 and comparative example 42 were evaluated under the same conditions as in Example 1 for the structure and cutting characteristics of the cemented carbide member. As a result, the binder phases of Invention Examples 35 to 41 contain 2% by mass of Sm and 0.5, 1, 2, 5, 9, 10, and 11% by mass of Cr, respectively. Comparative Example 42 contained 5% by mass of Co in the binder phase, but did not contain rare earth elements such as Sm. Further, in both inventive examples 35 to 41 and comparative example 42, the oxygen content in the region of about 0.5 μmφ where many rare earth elements are present is 0 to 0.2 mass%, J is 6 mass%, K / J was 0.3, L / M was 1.4, and I / J was 1.1. The evaluation results of these inventive examples and comparative examples are summarized in Table 2.

表２より、結合相中にＣｒをＣｏの５質量％含有しているもののＳｍ等の希土類元素を含有していない比較例４２は連続切削寿命が２２分、断続切削寿命が３１００回であるのに対して、結合相中にＳｍとともにＣｒをＣｏの５質量％含有している本発明例３８は連続切削寿命が５８分、断続切削寿命が４１００回であり、比較例４２に対して、連続切削寿命が２．６倍長く優れている。また、本発明例３５〜４１内を比較すると、Ｃｒ含有量が１質量％未満である本発明例３５や１０質量％を越えて大きい本発明例４１は、連続切削寿命が４３分以下、断続切削寿命が３８００回以下であるのに対して、結合相中にＣｒをＣｏの１〜１０質量％含有している本発明例３６〜４０は連続切削寿命が５５分以上、断続切削寿命が４１００回であり、連続切削寿命が２．６倍以上優れている。即ち、本発明の中でも結合相中にＣｒがＣｏの１〜１０質量％含有されていることが好ましい。   From Table 2, Comparative Example 42 containing 5 mass% of Co in the binder phase but containing no rare earth element such as Sm has a continuous cutting life of 22 minutes and an interrupted cutting life of 3100 times. On the other hand, the present invention example 38 containing 5 mass% of Co together with Sm in the binder phase has a continuous cutting life of 58 minutes and an interrupted cutting life of 4100 times. Cutting life is 2.6 times longer and better. Moreover, when the inside of this invention example 35-41 is compared, this invention example 35 whose Cr content is less than 1 mass% and this invention example 41 which is large exceeding 10 mass% have a continuous cutting life of 43 minutes or less, and intermittent. In contrast to the cutting life of 3800 times or less, Examples 36 to 40 of the present invention containing 1 to 10% by mass of Co in the binder phase have a continuous cutting life of 55 minutes or more and an intermittent cutting life of 4100. The continuous cutting life is 2.6 times or more. That is, in the present invention, it is preferable that 1 to 10% by mass of Cr is contained in the binder phase.

（実施例３）
希土類元素が存在する領域の酸素量が０〜５質量％であることの効果、及び、希土類元素用原料粉末として希土類元素とＣｏからなり、希土類とＣｏの比が１：２〜１：８．５であり、しかも酸素含有量が０．０１〜１質量％である合金を用いた場合の効果を評価するために、実施例１と同じ製造プロセスで、ＳｍとＣｏの比が１：２、１：５、１：８．５であるＳｍＣｏ２粗粉、ＳｍＣｏ５粗粉、Ｓｍ２Ｃｏ１７粗粉を作製した。また、比較のために、Ｓｍ金属とＣｏ金属とを１：１の割合で配合し窒素雰囲気中で単に機械的に混合したＳｍ金属とＣｏ金属との混合粉末を作製した。これらの粉末と、実施例１と同じ原料粉末を用いて、実施例１と同じ製造条件で同じ形状をもった超硬合金部材を製造し、実施例１と同じ条件で皮膜を形成することにより本発明例４３〜４９と比較例５０とを作製した。但し、本発明例４４は、実施例１と同じ条件でＳｍＣｏ５合金を作製した後、１〜２ｍｍの小粒に機械的に粉砕せずに直接、ＨＤプロセスにより粗粉化した。この粗粉をガス分析装置で評価した結果、合金中の酸素含有量はいずれも０．０１質量％であった。また、本発明例４５〜４８は、実施例１と同じ条件でＳｍＣｏ５合金を作製した後、１〜２ｍｍの小粒への機械的粉砕を、少量の酸素ガスを混入させた窒素雰囲気中（夫々、Ｏ２／Ｎ２：１、２、３、４ｖｏｌ％）で行った。作製した合金粉末中の酸素含有量はそれぞれ０．２、０．５、０．８、１質量％であった。
これら本発明例４３〜４９と比較例５０とを、実施例１と同じ条件で超硬合金製部材の組織と切削特性を評価した。まず、これら超硬合金部材の断面組織を、ＪＸＡ−８２００型のＥＰＭＡ装置により５０ｋ倍で観察した結果、比較例５０のＷＣ粒と結合相との界面近傍に約０．５μｍφの希土類元素の酸化物からなる析出物が観察された。この析出物の中央部を中心にして約０．５μｍφの領域の酸素量を測定した結果、酸素含有量が７質量％であった。これに対して、本発明例４３〜４５と４９は希土類元素の酸化物からなる析出物が観察されず、希土類元素が存在する領域の酸素含有量が０〜５質量％であった。また、本発明例４６〜４８は一部に希土類元素の酸化物からなる析出物が観察されるものの、その大きさは本発明例４６が約０．０５μｍ、本発明例４７が約０．１μｍ、本発明例４８は約０．１５μｍであり、これら析出物の中央部を中心にして測定した約０．５μｍφ領域の酸素含有量はそれぞれ１、３、５質量％であった。また、本発明例４３〜４９と比較例５０とはいずれも、Ｊが６質量％、Ｋ／Ｊが０．３、Ｌ／Ｍが１．４、Ｉ／Ｊが１．１であった。これらの本発明例と比較例の評価結果を表３にまとめて記した。 (Example 3)
The effect that the amount of oxygen in the region where the rare earth element exists is 0 to 5% by mass, and the rare earth element raw material powder is composed of rare earth element and Co, and the ratio of rare earth to Co is 1: 2 to 1: 8. In order to evaluate the effect when using an alloy having an oxygen content of 0.01 to 1% by mass, the ratio of Sm to Co is 1: 2, SmCo2 coarse powder, SmCo5 coarse powder, and Sm2Co17 coarse powder of 1: 5 and 1: 8.5 were prepared. For comparison, a mixed powder of Sm metal and Co metal was prepared by blending Sm metal and Co metal at a ratio of 1: 1 and simply mechanically mixed in a nitrogen atmosphere. By using these powders and the same raw material powder as in Example 1 to manufacture a cemented carbide member having the same shape under the same manufacturing conditions as in Example 1, and forming a film under the same conditions as in Example 1 Invention Examples 43 to 49 and Comparative Example 50 were produced. However, in Example 44 of the present invention, an SmCo5 alloy was produced under the same conditions as in Example 1, and then directly coarsened by the HD process without being mechanically pulverized into 1-2 mm granules. As a result of evaluating this coarse powder with a gas analyzer, the oxygen content in the alloy was 0.01% by mass. Inventive Examples 45 to 48 were prepared by producing SmCo5 alloy under the same conditions as in Example 1, and then mechanically pulverizing into 1 to 2 mm small particles in a nitrogen atmosphere mixed with a small amount of oxygen gas (respectively, O2 / N2: 1, 2, 3, 4 vol%). The oxygen content in the produced alloy powder was 0.2, 0.5, 0.8, and 1% by mass, respectively.
The inventive examples 43 to 49 and comparative example 50 were evaluated under the same conditions as in Example 1 for the structure and cutting characteristics of the cemented carbide member. First, as a result of observing the cross-sectional structure of these cemented carbide members with a JXA-8200 type EPMA apparatus at a magnification of 50 k, oxidation of a rare earth element of about 0.5 μmφ in the vicinity of the interface between the WC grains and the binder phase of Comparative Example 50 A precipitate consisting of a product was observed. As a result of measuring the amount of oxygen in the region of about 0.5 μmφ centering on the central portion of the precipitate, the oxygen content was 7% by mass. On the other hand, in Examples 43 to 45 and 49 of the present invention, precipitates composed of oxides of rare earth elements were not observed, and the oxygen content in the region where the rare earth elements were present was 0 to 5% by mass. Further, in the inventive examples 46 to 48, although precipitates composed of rare earth oxides are observed in part, the size of the inventive example 46 is about 0.05 μm, and the inventive example 47 is about 0.1 μm. Inventive Example 48 was about 0.15 μm, and the oxygen content in the region of about 0.5 μmφ measured around the center of these precipitates was 1, 3, and 5% by mass, respectively. In each of Invention Examples 43 to 49 and Comparative Example 50, J was 6% by mass, K / J was 0.3, L / M was 1.4, and I / J was 1.1. The evaluation results of these inventive examples and comparative examples are summarized in Table 3.

表３より、希土類元素が存在する領域の酸素量が５質量％を越えて大きい比較例５０と、同酸素量が０〜５質量％である本発明例４３〜４９とを比較すると、比較例５０の連続切削寿命が３５分、断続切削寿命が１３００回であるのに対して、本発明例４３〜４９は連続切削寿命が３６分以上、断続切削寿命が２７００回以上であり、断続切削寿命が２倍以上長く、本発明例は、格段に優れた工具特性を有している。
また、希土類元素用原料粉末として、比較例５０は、Ｓｍ金属とＣｏ金属とを１：１の割合で配合し窒素雰囲気中で単に機械的に混合したＳｍ金属とＣｏ金属の混合粉末を用いて作製しているのに対して、本発明例は、いずれも原料粉末として、希土類元素とＣｏとの比が１：２〜１：８．５であり、しかも、酸素含有量が０．０１〜１質量％である希土類元素とＣｏからなる合金粉末を用いており、本発明の製造方法が格段に優れた希土類元素含有超硬合金の製造方法であることが明らかである。
また、本発明例４４〜４８内を比較すると、含有酸素量が０．０１〜１質量％である希土類−Ｃｏ合金粉末を用いて作製し、超硬合金部材中の希土類元素が存在する領域の酸素量が１〜５質量％である本発明例４６〜４８の断続切削寿命が２８００回以下であるのに対して、該合金粉末の酸素量が０．０１〜０．２質量％であり、超硬合金部材中の該酸素量が０〜０．５質量％である本発明例４４と４５とは断続切削寿命が３７００回以上であり、１．３倍以上長く、優れている。従って、本発明は、希土類元素が存在する領域の酸素量が０〜０．５質量％であることが好ましく、本発明の製造方法は、酸素含有量が０．０１〜０．２質量％である希土類元素−Ｃｏ合金を用いることが好ましい。 From Table 3, when Comparative Example 50 in which the amount of oxygen in the region where the rare earth element is present is larger than 5% by mass and Invention Examples 43 to 49 in which the amount of oxygen is 0 to 5% by mass are compared, Comparative Example While the continuous cutting life of 50 is 35 minutes and the interrupted cutting life is 1300 times, Examples 43 to 49 of the present invention have a continuous cutting life of 36 minutes or more and an interrupted cutting life of 2700 times or more. Is twice or longer, and the examples of the present invention have remarkably excellent tool characteristics.
Further, as a rare earth element raw material powder, Comparative Example 50 uses a mixed powder of Sm metal and Co metal, in which Sm metal and Co metal are blended at a ratio of 1: 1 and simply mechanically mixed in a nitrogen atmosphere. Whereas the examples of the present invention are all raw material powders, the ratio of rare earth elements to Co is 1: 2 to 1: 8.5, and the oxygen content is 0.01 to It is apparent that 1% by mass of an alloy powder composed of rare earth element and Co is used, and the production method of the present invention is a remarkably excellent method for producing a rare earth element-containing cemented carbide.
Moreover, when the inside of this invention example 44-48 is compared, it produces using the rare earth-Co alloy powder whose oxygen content is 0.01-1 mass%, and the area | region where the rare earth element in a cemented carbide member exists. While the interrupted cutting life of Examples 46 to 48 of the present invention examples 46 to 48 having an oxygen amount of 1 to 5% by mass is 2800 times or less, the oxygen amount of the alloy powder is 0.01 to 0.2% by mass, Inventive Examples 44 and 45 in which the oxygen content in the cemented carbide member is 0 to 0.5% by mass are excellent in that the interrupted cutting life is 3700 times or more, 1.3 times or more. Therefore, in the present invention, the oxygen content in the region where the rare earth element is present is preferably 0 to 0.5% by mass, and the production method of the present invention has an oxygen content of 0.01 to 0.2% by mass. It is preferable to use a certain rare earth element-Co alloy.

図１は、本発明例１６のＣｏとＳｍ組成分布状況を示す。FIG. 1 shows the Co and Sm composition distribution of Example 16 of the present invention. 図２は、本発明例１６のＺｒとＮｂ組成分布状況を示す。FIG. 2 shows the Zr and Nb composition distribution of Example 16 of the present invention.

Claims (9)

主に鉄族金属からなる結合相と、周期律表４ａ、５ａ、６ａ族金属から選択されるＷ以外の少なくとも１種以上の炭化物固溶体、窒化物固溶体、炭窒化物固溶体の少なくとも１種以上を含有する硬質相、及び残ＷＣと不可避不純物とから成る超硬合金部材の表面に、硬質皮膜が単層又は多重層被覆されており、該皮膜直下の部材表面から深さ方向に１〜１００μｍの領域に亘って前記硬質相が消失又は減少している硬質相貧化表面帯域が存在し、該硬質相貧化表面帯域に隣接して更に深さ方向に１〜２００μｍの領域に亘って硬質相富化中間帯域が存在している被覆超硬合金部材であり、該結合相中に希土類元素が含有され、かつ、希土類元素が存在する領域の酸素量が０〜５質量％であることを特徴とする被覆超硬合金部材。 At least one of a binder phase mainly composed of an iron group metal and at least one carbide solid solution other than W selected from the periodic table 4a, 5a, and 6a group metals, a nitride solid solution, and a carbonitride solid solution. A hard coating is coated with a single layer or multiple layers on the surface of a cemented carbide member composed of the hard phase and the remaining WC and inevitable impurities, and 1-100 μm in the depth direction from the surface of the member immediately below the coating. There exists a hard phase-depleted surface zone in which the hard phase has disappeared or decreased over a region, and the hard phase is further adjacent to the hard phase-depleted surface zone over a region of 1 to 200 μm in the depth direction. A coated cemented carbide member having an enriched intermediate zone, wherein the binder phase contains a rare earth element, and the oxygen content in a region where the rare earth element is present is 0 to 5 mass%. A coated cemented carbide member. 請求項１に記載の被覆超硬合金部材において、該硬質相富化中間帯域内の硬質相を構成する金属成分含有量Iと該超硬合金部材内部の硬質相を構成する金属成分含有量Ｊの比率Ｉ／Ｊが１．０５〜１．３であることを特徴とする被覆超硬合金部材。 The coated cemented carbide member according to claim 1, wherein the metal component content I constituting the hard phase in the hard phase enriched intermediate zone and the metal component content J constituting the hard phase inside the cemented carbide member. A coated cemented carbide member having a ratio I / J of 1.05 to 1.3. 請求項１又は２に記載の被覆超硬合金部材において、該超硬合金部材内部における結合相の希土類元素含有量が、結合相を構成する鉄族金属含有量に対して、０．１〜１０質量％であることを特徴とする被覆超硬合金部材。 The coated cemented carbide member according to claim 1 or 2, wherein the rare earth element content of the binder phase inside the cemented carbide member is 0.1 to 10 with respect to the iron group metal content constituting the binder phase. A coated cemented carbide member characterized by being in mass%. 請求項１から３のいずれかに記載の被覆超硬合金部材において、該Ｊが、質量％で１．５≦Ｊ≦１５であることを特徴とする被覆超硬合金部材。 4. The coated cemented carbide member according to claim 1, wherein J is 1.5 ≦ J ≦ 15 by mass%. 5. 請求項１から４のいずれかに記載の被覆超硬合金部材において、該硬質相貧化表面帯域内の硬質相を構成する金属成分含有量をＫとし、該Ｊとの両者の比率Ｋ／Ｊが、０．１≦Ｋ／Ｊ≦０．７であり、該硬質相貧化表面帯域内の結合相を構成する金属成分含有量をＬとし、該超硬合金部材内部の結合相を構成する金属成分含有量をＭとしとした時、両者の比率Ｌ／Ｍが、１．１≦Ｌ／Ｍ≦１．８であることを特徴とする被覆超硬合金部材。 5. The coated cemented carbide member according to claim 1, wherein the content of the metal component constituting the hard phase in the hard phase-depleted surface zone is K, and the ratio of both to J is K / J. Is 0.1 ≦ K / J ≦ 0.7, the metal component content constituting the binder phase in the hard phase-depleted surface zone is L, and the binder phase inside the cemented carbide member is constituted. A coated cemented carbide member having a ratio L / M of 1.1 ≦ L / M ≦ 1.8 when the metal component content is M. 請求項１から５のいずれかに記載の被覆超硬合金部材において、該希土類元素に少なくともＳｍ及び／又はＧｄが含まれていることを特徴とする被覆超硬合金部材。 The coated cemented carbide member according to any one of claims 1 to 5, wherein the rare earth element contains at least Sm and / or Gd. 請求項１から６のいずれかに記載の被覆超硬合金部材において、結合相にＣｒがＣｏの１〜１０質量％含有されていることを特徴とする被覆超硬合金部材。 The coated cemented carbide member according to any one of claims 1 to 6, wherein the binder phase contains Cr in an amount of 1 to 10% by mass of Co. 請求項１から７のいずれかに記載の被覆超硬合金部材において、該硬質相中にＺｒが含有されていることを特徴とする被覆超硬合金部材。 The coated cemented carbide member according to any one of claims 1 to 7, wherein Zr is contained in the hard phase. 希土類元素用原料粉末として希土類元素とＣｏからなり、希土類とＣｏのモル比が１：２〜１：８．５であり、しかも酸素含有量が０．０１〜１質量％である合金を用いたことを特徴とする希土類元素含有超硬合金の製造方法。
As the rare earth element raw material powder, an alloy made of rare earth element and Co, having a molar ratio of rare earth to Co of 1: 2 to 1: 8.5 and an oxygen content of 0.01 to 1% by mass was used. A process for producing a rare earth element-containing cemented carbide characterized by the above.

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