JPH0450385B2 - - Google Patents
Info
- Publication number
- JPH0450385B2 JPH0450385B2 JP56173330A JP17333081A JPH0450385B2 JP H0450385 B2 JPH0450385 B2 JP H0450385B2 JP 56173330 A JP56173330 A JP 56173330A JP 17333081 A JP17333081 A JP 17333081A JP H0450385 B2 JPH0450385 B2 JP H0450385B2
- Authority
- JP
- Japan
- Prior art keywords
- cemented carbide
- solid solution
- substrate
- type solid
- coated
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
- C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
- C23C16/34—Nitrides
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Cutting Tools, Boring Holders, And Turrets (AREA)
- Chemical Vapour Deposition (AREA)
Description
〔産業上の利用分野〕
本発明は被覆超硬合金に関するものである。
〔従来技術及びその問題点〕
超硬合金にHfN硬質皮膜を被覆した被覆超硬
合金は耐摩耗性、耐溶着性、耐化学反応性に優れ
広く実用に供されている。
しかし基体と皮膜の接着強度はまだ十分とはい
えず仕上げ用に用いられないとか、カツター用に
は供せられないなど実用面からは制限も多い。こ
の接着強度は基体一皮膜物質の物理的、化学的な
接合ばかりでなく、切削時には熱膨張の相違も影
響を及ぼす。このため今日まで種々の界面強度改
善案が研究されている。例えば、基体は従来の超
硬合金とはやや組成の異なつたもの、すなわち
Co金属の含有量を低減して化学的な接着強度を
増加したり、あるいはNbC含有量を増加させて
基体と皮膜の熱膨張率を近づける等の方法が用い
られている。
〔問題点を解決する為の手段〕
本発明者らは上記従来技術の欠点を改良し、超
硬基体と皮膜の接着強度を改善し、熱衝撃性、機
械的靭性に優れる被覆超硬合金を得べく研究を重
ねた結果、皮膜物質と類似の相を基体表面に富化
する事によつて接着強度を向上させる事を見出し
た。すなわち、本発明の特徴は超硬合金基体の表
面にCo金属がほとんど存在せず、かつＢ−１型
固溶体炭窒化物相が富化された基体を用い、その
表面にHfNを被覆する点にある。Ｂ−１型固溶
体は周期律表の４ａ，５ａ及び６ａ族の金属の炭
化物及び窒化物の一種または２種以上からなる
NaCl型結晶構造化合物である。
このような基体を得る方法はすでに、特開昭55
−154561号広報で公知の如く、焼結雰囲気中の
N2分圧を調整することによつて可能である。す
なわち該超硬合金基体のＢ−１型固溶体の平衡
N2分圧よりも焼結雰囲気のN2分圧を大きくする
ことによつてＢ−１型固溶体と結合相の濡れ性の
関係から表面上にはほとんどCo金属は存在しな
くなり、かつＢ−１型固溶体がほぼ完全に表面を
覆つてしまう。
本発明の特徴は、Ｂ−１型固溶体が表面に富化
された基体にHfNを被覆することにあり、Al2O3
またはZrO2を直接被覆することを特徴とする特
開昭55−154561号広報記載の発明とは明かに相違
するものである。
以上の効果によつて、従来のHfN被覆超硬合
金と比較して本発明が優れる理由は、
基体表面に富化されたＢ−１型固溶体はＮが
気相より拡散して炭窒化となつており皮膜
HfNとの接着強度が著しく向上すること。
Ｂ−１型固溶体とHfN被膜の熱膨張率の差
は基体とHfN被膜の熱膨張率よりも小さいた
め切削中の被膜剥離が少ないこと。
基体−皮膜界面にCo金属がほとんど存在し
ないために界面強度が上昇すると共に、基体か
ら皮膜へのCoの拡散がないために皮膜の耐摩
耗性が著しく向上すること。
またHfNを被覆した場合、HfNがＢ−１型固
溶体の構成要素であるTi化合物と同様な結晶構
造をしているため、特に表面に富化しているＢ−
１型固溶体とは良く密着し、脆化反応を生じな
い。さらに、直接酸化物を被覆する場合とを比較
するとＢ−１型固溶体中のTi、Ｗと酸化物が化
学反応をおこし非常に脆いTi、Ｗの酸化物が界
面に生じることが確かめられ界面強度が低下す
る。この点が先に引用した特開昭55−154561号広
報記載の発明からは容易に推考出来ない技術的事
項である。
次に、この発明の被覆超硬合金において前述の
数値限定した理由について述べる。
(1) Ｂ−１型固溶体
Ｂ−１型固溶体の量が40％未満では化学的被
覆処理を行うと脆化相（イータ相）が発生しや
すくなり、かつ基体と皮膜の熱膨張差が十分い
縮まらず切削時の剥離強度が向上しない。また
80％未満としたのはＢ−１型固溶体が本質的に
脆く、欠損しやすくなるためである。
(2) Co量
基体表面近傍のCo量を超硬合金内部でのCo
含有量の20％以下としたのは、20％を越すと皮
膜との接着強度が劣化し、かつ皮膜の耐摩耗性
が減ずるためである。
(3) Ｂ−１型固溶体の厚さ
Ｂ−１型固溶体を富化した層の厚みを、少な
くとも1μmとしたのは、それ以下では、脆化反
応相（イータ相）により、切削時の剥離等が生
じるためである。
次に本発明被覆超硬合金を実施例によつて具
体的にその特性を説明する。
実施例 １
72WC−10TiC−10TaC−8Coなる粉末を配合
し、前記混合粉末を乾燥後、プレスして圧粉体を
形成し、さらに前記圧粉体を10-2〜10-3mmHgの
真空中で１時間焼結した後、N2ガス5Torr導入
しそのまま冷却して本発明超硬合金の基体(A)を製
造した。また比較の目的で前記粉末と同一の工程
で製作しN2導入を行わず、真空中で冷却した基
体(B)を製造した。次にこの基体上にHfl4、N2ガ
スを用いて化学蒸着処理を行いHfN6μmの厚さ
に被覆した。
次に、表面近傍の各相の量及び厚さを測定する
ため、チツプを研摩しSEM／EDXにて分析及び
組織観察を行つた。その結果を表１に示す。
[Industrial Field of Application] The present invention relates to a coated cemented carbide. [Prior art and its problems] Coated cemented carbide, which is a cemented carbide coated with an HfN hard film, has excellent wear resistance, welding resistance, and chemical reaction resistance, and is widely used in practical use. However, there are many limitations from a practical standpoint, such as the adhesion strength between the substrate and the film being insufficient, making it unusable for finishing purposes, or for cutters. This adhesive strength is affected not only by the physical and chemical bonding between the substrate and the coating material, but also by the difference in thermal expansion during cutting. For this reason, various plans for improving the interfacial strength have been studied to date. For example, the base material has a slightly different composition from conventional cemented carbide, i.e.
Methods used include reducing the Co metal content to increase the chemical bonding strength, or increasing the NbC content to bring the thermal expansion coefficients of the substrate and film closer to each other. [Means for Solving the Problems] The present inventors have improved the drawbacks of the above-mentioned prior art, improved the adhesive strength between the cemented carbide substrate and the film, and created a coated cemented carbide that has excellent thermal shock resistance and mechanical toughness. As a result of repeated research, it was discovered that adhesive strength can be improved by enriching the substrate surface with a phase similar to the coating material. In other words, the present invention is characterized by using a cemented carbide substrate with almost no Co metal on its surface and enriched with B-1 type solid solution carbonitride phase, and coating the surface with HfN. be. The B-1 type solid solution consists of one or more carbides and nitrides of metals in Groups 4a, 5a, and 6a of the periodic table.
It is a compound with NaCl type crystal structure. A method for obtaining such a substrate has already been published in JP-A-55
- As known from Publication No. 154561, in the sintering atmosphere
This is possible by adjusting the N2 partial pressure. In other words, the equilibrium of the B-1 type solid solution in the cemented carbide substrate
By increasing the N2 partial pressure in the sintering atmosphere than the N2 partial pressure, almost no Co metal will exist on the surface due to the wettability of the B-1 type solid solution and the binder phase, and B- The type 1 solid solution almost completely covers the surface. The feature of the present invention is that HfN is coated on a substrate whose surface is enriched with B-1 type solid solution, and Al 2 O 3
This invention is clearly different from the invention described in JP-A-55-154561, which is characterized in that ZrO 2 is directly coated. Due to the above effects, the reason why the present invention is superior to conventional HfN-coated cemented carbide is that the B-1 type solid solution enriched on the base surface allows N to diffuse from the gas phase and become carbonitrided. Ori film
Significant improvement in adhesive strength with HfN. The difference in thermal expansion coefficient between the B-1 type solid solution and the HfN coating is smaller than that between the base and the HfN coating, so there is little peeling of the coating during cutting. Almost no Co metal exists at the substrate-coating interface, which increases the interfacial strength, and because there is no diffusion of Co from the substrate to the coating, the wear resistance of the coating significantly improves. In addition, when HfN is coated, HfN has a crystal structure similar to that of the Ti compound, which is a component of the B-1 type solid solution, so the B-
It adheres well to type 1 solid solution and does not cause any embrittlement reactions. Furthermore, when comparing the case of directly coating the oxide, it was confirmed that the Ti and W in the B-1 solid solution and the oxide caused a chemical reaction, and very brittle Ti and W oxides were formed at the interface. decreases. This point is a technical matter that cannot be easily deduced from the invention described in the publication of JP-A-55-154561 cited above. Next, the reason for the above-mentioned numerical limitations in the coated cemented carbide of the present invention will be described. (1) B-1 type solid solution If the amount of B-1 type solid solution is less than 40%, a brittle phase (eta phase) is likely to occur when chemical coating treatment is performed, and the difference in thermal expansion between the substrate and the coating is sufficient. It does not shrink and the peel strength during cutting does not improve. Also
The reason why it is set to less than 80% is that the B-1 type solid solution is inherently brittle and easily breaks. (2) Co content The Co content near the base surface is the Co content inside the cemented carbide.
The reason why the content is set to 20% or less is because if it exceeds 20%, the adhesive strength with the film will deteriorate and the abrasion resistance of the film will decrease. (3) Thickness of B-1 type solid solution The reason why the thickness of the layer enriched with B-1 type solid solution was set to at least 1 μm is that if it is less than that, the embrittlement reaction phase (eta phase) will cause peeling during cutting. This is because such problems occur. Next, the characteristics of the coated cemented carbide of the present invention will be specifically explained using examples. Example 1 A powder of 72WC-10TiC-10TaC-8Co was blended, the mixed powder was dried and pressed to form a green compact, and the green compact was further vacuumed at 10 -2 to 10 -3 mmHg. After sintering for 1 hour, 5 Torr of N 2 gas was introduced and the material was cooled to produce a substrate (A) of the cemented carbide of the present invention. In addition, for comparison purposes, a substrate (B) was produced using the same process as the powder described above, without introducing N2 , and cooled in vacuum. Next, this substrate was coated with HfN to a thickness of 6 μm by chemical vapor deposition using Hfl 4 and N 2 gas. Next, in order to measure the amount and thickness of each phase near the surface, the chip was polished and analyzed and observed by SEM/EDX. The results are shown in Table 1.
【表】
これら２種を以下の切削条件、すなわち
被削材 SCM3
切削速度 250m／min
送り 0.4mm／rev
切り込み 1.5mm
水溶性切削油使用
で切削試験を行つた。
比較品のＢチツプは被覆膜が剥離し、15分間し
か切削出来なかつたのに対し、本発明のチツプＡ
は30分間の切削でも剥離は発生せず良好な摩耗形
態を示した。
実施例 ２
79WC−3TiC−3TiN−4TaC−2NbC−9Coな
る粉末を配合し、前記混合粉末を乾燥後、プレス
して圧粉体を形成し、さらに前記圧粉体を10-2〜
10-3mmHgの真空中で１時間焼結した後、N2ガス
100Torr導入しそのまま冷却して本発明超硬合金
の基体(C)を製造した。また比較の目的で前記粉末
と同一の工程で製作したN2導入を行わず、真空
中で冷却した基体(D)を製造した。次にこの基体上
にHfl4、N2ガスを用いて化学蒸着処理を行い
HfN6μmの厚さに被覆した。
次に、表面近傍の各相の量及び厚さを測定する
ため、チツプを研摩しSEM／EDXにて分析及び
組織観察を行つた。その結果を表２に示す。[Table] Cutting tests were conducted on these two types under the following cutting conditions: Work material: SCM3 Cutting speed: 250 m/min Feed: 0.4 mm/rev Depth of cut: 1.5 mm Using water-soluble cutting oil. The comparative chip B had its coating peeled off and could only be cut for 15 minutes, whereas the chip A of the present invention could only be cut for 15 minutes.
showed a good wear pattern with no peeling even after 30 minutes of cutting. Example 2 A powder of 79WC-3TiC-3TiN-4TaC-2NbC-9Co is blended, the mixed powder is dried and then pressed to form a green compact, and the green compact is further heated to a temperature of 10 -2 ~
After sintering for 1 hour in a vacuum of 10 -3 mmHg, N2 gas
A base body (C) of the cemented carbide of the present invention was produced by introducing 100 Torr and cooling it as it was. In addition, for comparison purposes, a substrate (D) was produced in the same process as the powder, but without introducing N 2 and cooled in vacuum. Next, chemical vapor deposition treatment is performed on this substrate using Hfl 4 and N 2 gas.
HfN was coated to a thickness of 6 μm. Next, in order to measure the amount and thickness of each phase near the surface, the chip was polished and analyzed and observed by SEM/EDX. The results are shown in Table 2.
上述のように、本発明被覆超硬合金は、表面の
Co量を減少させ、かつ表面にＢ−１型固溶体を
富化した超硬合金基体上に、HfNを被覆するこ
とによつて、基体と皮膜の界面強度を向上させ熱
衝撃、機械的衝撃に富む被覆超硬合金を得ること
が出来る。
As mentioned above, the coated cemented carbide of the present invention has a surface
By coating HfN on a cemented carbide substrate with a reduced amount of Co and enriched with B-1 type solid solution on the surface, the interfacial strength between the substrate and the coating is improved and it is resistant to thermal shock and mechanical shock. A richly coated cemented carbide can be obtained.
Claims (1)
を鉄族金属で結合した超硬合金にHfNを被覆し
た超硬合金において、被覆膜と接する超硬合金の
表面から少なくとも1μmの深さの部分における
Co量が超硬合金の十分内部におけるCo量の20％
以下であり、かつＢ−１型固溶体が40容量％以上
80容量％未満含まれることを特徴とする被覆超硬
合金。1 In a cemented carbide in which WC and B-1 type solid solution are used as a hard phase, and these are bonded with an iron group metal and coated with HfN, a depth of at least 1 μm from the surface of the cemented carbide in contact with the coating film is applied. in the part of
The amount of Co is 20% of the amount of Co inside the cemented carbide.
or less, and the B-1 type solid solution is 40% by volume or more
A coated cemented carbide characterized in that it contains less than 80% by volume.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17333081A JPS5873763A (en) | 1981-10-29 | 1981-10-29 | Coated sinteredhard alloy and its production thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17333081A JPS5873763A (en) | 1981-10-29 | 1981-10-29 | Coated sinteredhard alloy and its production thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5873763A JPS5873763A (en) | 1983-05-04 |
| JPH0450385B2 true JPH0450385B2 (en) | 1992-08-14 |
Family
ID=15958425
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17333081A Granted JPS5873763A (en) | 1981-10-29 | 1981-10-29 | Coated sinteredhard alloy and its production thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5873763A (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55154562A (en) * | 1979-05-18 | 1980-12-02 | Sumitomo Electric Ind Ltd | Sintered hard alloy part for base material of surface-covered tool material and their manufacture |
-
1981
- 1981-10-29 JP JP17333081A patent/JPS5873763A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5873763A (en) | 1983-05-04 |
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