JPS648688B2 - - Google Patents
Info
- Publication number
- JPS648688B2 JPS648688B2 JP773784A JP773784A JPS648688B2 JP S648688 B2 JPS648688 B2 JP S648688B2 JP 773784 A JP773784 A JP 773784A JP 773784 A JP773784 A JP 773784A JP S648688 B2 JPS648688 B2 JP S648688B2
- Authority
- JP
- Japan
- Prior art keywords
- sintered body
- diamond
- powder
- metal
- sintered
- 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
Links
- 239000010432 diamond Substances 0.000 claims description 35
- 229910003460 diamond Inorganic materials 0.000 claims description 34
- 239000000843 powder Substances 0.000 claims description 27
- 229910052751 metal Inorganic materials 0.000 claims description 23
- 239000002184 metal Substances 0.000 claims description 23
- 238000005245 sintering Methods 0.000 claims description 10
- 239000003054 catalyst Substances 0.000 claims description 9
- 230000015572 biosynthetic process Effects 0.000 claims description 6
- 238000003786 synthesis reaction Methods 0.000 claims description 6
- 229910045601 alloy Inorganic materials 0.000 claims description 4
- 239000000956 alloy Substances 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 239000002994 raw material Substances 0.000 claims description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 2
- 229910052804 chromium Inorganic materials 0.000 claims description 2
- 229910052748 manganese Inorganic materials 0.000 claims description 2
- 230000000737 periodic effect Effects 0.000 claims description 2
- 229910052715 tantalum Inorganic materials 0.000 claims description 2
- 238000005520 cutting process Methods 0.000 description 9
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical class [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 6
- 239000013078 crystal Substances 0.000 description 5
- 229910002804 graphite Inorganic materials 0.000 description 5
- 239000010439 graphite Substances 0.000 description 5
- 238000005087 graphitization Methods 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 239000012535 impurity Substances 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 239000012071 phase Substances 0.000 description 4
- 239000007858 starting material Substances 0.000 description 4
- 239000011230 binding agent Substances 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000005491 wire drawing Methods 0.000 description 3
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 238000005553 drilling Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- -1 ferrous metals Chemical class 0.000 description 2
- 229910009043 WC-Co Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Landscapes
- Powder Metallurgy (AREA)
Description
(イ) 技術分野
この発明は切削工具、掘削工具、線引きダイス
等の工具に使用されるダイヤモンド微粉末の焼結
体の製造法に関するものである。
(ロ) 従来技術とその問題点
ダイヤモンドの微粉末を超高圧下で焼結した焼
結体は、既に非鉄金属類の切削加工用工具、ドリ
ルビツト、線引きダイスなどとして広く使用され
ている。
この焼結体は例えば特公昭52−12126号に記載
されている方法によれば、ダイヤモンドの粉末を
WC―Co超硬合金の成形体もしくは焼結体に接す
るように配置し、超硬合金の液相が生じる温度以
上で超高圧下で焼結される。
このとき超硬合金中のCoの一部がダイヤモン
ド粉末層中に侵入し、結合金属として作用する。
この方法で作られた焼結体は、約10〜15体積%
のCoを焼結体中に含有する。
この焼結体は非鉄金属等の切削加工用工具とし
ては十分実用的な性能を有しているが、反面耐熱
性が劣るという欠点がある。例えば、この焼結体
を750℃以上に加熱すると、耐摩耗性、強度の低
下が見られ、900℃以上では焼結体が破壊してし
まう。この理由はダイヤモンド粒子と結合材Co
の界面においてダイヤモンドの黒鉛化が生じるこ
と、および両者の加熱時における熱膨張率の差に
よる熱応力が原因と考えられている。
またこのCoを結合材とした焼結体を酸処理し
て大部分の結合金属相を除外したものは、焼結体
の耐熱性が向上することが知られている。
例えば特開昭53−114589号公報には、耐熱性の
改良されたダイヤモンド焼結体の製造法が開示さ
れている。ところが、この場合は除去された結合
金属相の部分は空孔となるため、どうしても強度
が低下してしまう。
一方ダイヤモンドの粉末のみを超高圧下で焼結
する試みも、これまでになされているが、ダイヤ
モンド粒子が変形し難いために粒子の間隙には圧
力が伝達されず、黒鉛化が生じ、ダイヤ―黒鉛の
複合体しか得られていない。
(ハ) 発明の構成
この発明は、従来の焼結ダイヤモンドの欠点で
あつた耐熱性を改良した高強度の焼結体を得る新
しい製法に関するものである。
この発明では原料粉末として、合成ダイヤモン
ド粉末で、合成時に触媒として使用された周期律
表第8族鉄族金属、Cr、Mn、Taもしくはこれ
らを含む合金を不純物として結晶内に包含するも
のを用いる。
合成ダイヤモンド粉末は、その成長条件による
が、結晶内部の特定の面または方位に合成時に使
用された触媒金属を取り込んで成長する場合があ
る。
本発明者らは、このような介在物を特定量含有
する合成ダイヤモンド粉末を選択し、さらに焼結
前にこれを加熱してダイヤモンドの一部または全
部を黒鉛化せしめた。この黒鉛化処理を施こした
粉末を容器に充填し、高圧、高温で焼結を行なつ
た。
その結果、1〜10重量%の金属不純物を包含す
る合成ダイヤモンド粉末を出発原料とした場合に
は黒鉛化したダイヤモンドが焼結時に再びダイヤ
モンドに転換し、緻密な焼結体が得られることを
見出した。
また比較のために1〜10重量%の触媒金属粉末
を比較的に不純物の含有量の少ない合成ダイヤモ
ンド粉末を加熱してダイヤモンドの一部または全
部を黒鉛化せしめたものと混合して焼結したが、
この場合は充分緻密な焼結体が得られず、黒鉛が
残留していることがわかつた。
このことからダイヤモンドの合成時に内部に取
り込まれた触媒金属と、後から混入した触媒金属
とは焼結時の作用が異なることが推察される。
この発明の方法によるダイヤモンド焼結体は、
焼結体中に触媒金属を含有してるため、前記した
ように耐熱性の点では充分な改良は果せないと思
われたが、実験の結果をみると、耐熱性が大幅に
改良され、1000℃の加熱にも耐えられることがわ
かつた。
この理由は、第1に従来のCoを溶浸せしめる
方法の焼結体よりも金属含有量が少ないこと、第
2にその金属の分布状態が異なることが考えられ
る。
即ちこの発明の焼結体では、結晶粒が相互に極
めて密接に接合し、触媒金属は結晶粒界よりもむ
しろ結晶粒内に球状または板状の析出物として存
在する。
一方、従来の焼結体では触媒金属はダイヤモン
ド粒子相互の界面に薄いフイルム状として存在す
る。これは焼結時にダイヤモンド粉末の隙間に侵
入してくるCoを結合相としているためである。
この結果、この発明の焼結体では金属相とダイ
ヤモンドの接触面積は相対的に少なく、加熱によ
る結晶粒界の黒鉛化が生じ難いことにより耐熱性
が著しく改良されるものと考えられる。
この発明の実施に当つて、出発原料である合成
ダイヤモンドは1〜10重量%の触媒金属またはそ
れを含む合金を結晶内に含有するものを用いる。
ここで合成ダイヤモンドに含有する触媒金属ま
たはそれを含む合金を1〜10重量%の範囲とする
のは、1重量%未満では焼結が困難となり、また
10重量%以上では焼結体の耐熱性が低下して好ま
しくないためである。
出発原料の黒鉛化は、焼結性の改善のために必
要であり、約1400℃以上でダイヤモンド粉末を真
空または非酸化性雰囲気中で加熱して行なう。
焼結は、ベルト型超高圧装置等の超高圧装置を
用い、少なくとも50Kb以上、1400℃以上で行な
う。
以下実施例により詳細に説明する。
実施例 1
出発原料とて平均粒度が25μの下記第1表に示
す金属不純物を含む合成ダイヤモンド粉末を使用
した。
(a) Technical Field The present invention relates to a method for producing a sintered body of fine diamond powder used for tools such as cutting tools, drilling tools, and wire drawing dies. (b) Prior art and its problems Sintered bodies made by sintering fine diamond powder under ultra-high pressure are already widely used as tools for cutting non-ferrous metals, drill bits, wire drawing dies, etc. This sintered body can be made by adding diamond powder, for example, according to the method described in Japanese Patent Publication No. 52-12126.
It is placed in contact with a compact or sintered body of WC-Co cemented carbide, and is sintered under ultra-high pressure at a temperature above which the liquid phase of the cemented carbide occurs. At this time, some of the Co in the cemented carbide penetrates into the diamond powder layer and acts as a binding metal. The sintered body made by this method is approximately 10-15% by volume.
of Co is contained in the sintered body. Although this sintered body has sufficient practical performance as a cutting tool for non-ferrous metals, it has the disadvantage of poor heat resistance. For example, if this sintered body is heated to 750°C or higher, the wear resistance and strength will decrease, and if it is heated to 900°C or higher, the sintered body will break. The reason for this is that the diamond particles and the binder Co
The cause is thought to be graphitization of diamond at the interface between the two, and thermal stress due to the difference in thermal expansion coefficients during heating of the two. It is also known that when a sintered body using Co as a binder is treated with an acid to remove most of the binding metal phase, the heat resistance of the sintered body is improved. For example, JP-A-53-114589 discloses a method for producing a diamond sintered body with improved heat resistance. However, in this case, the removed portions of the bonded metal phase become pores, which inevitably leads to a decrease in strength. On the other hand, attempts have been made to sinter only diamond powder under ultra-high pressure, but since diamond particles are difficult to deform, pressure is not transmitted to the gaps between particles, resulting in graphitization and diamond Only graphite composites have been obtained. (C) Structure of the Invention The present invention relates to a new manufacturing method for obtaining a high-strength sintered body that improves heat resistance, which is a drawback of conventional sintered diamond. In this invention, as the raw material powder, synthetic diamond powder is used, which contains as an impurity in the crystal a metal of the iron group of group 8 of the periodic table, Cr, Mn, Ta, or an alloy containing these, which was used as a catalyst during synthesis. . Depending on the growth conditions, synthetic diamond powder may grow with the catalyst metal used during synthesis incorporated into a specific plane or orientation within the crystal. The present inventors selected a synthetic diamond powder containing a specific amount of such inclusions, and further heated it before sintering to graphitize some or all of the diamond. This graphitized powder was filled into a container and sintered at high pressure and high temperature. As a result, they found that when synthetic diamond powder containing 1 to 10% by weight of metal impurities was used as a starting material, graphitized diamond was converted back into diamond during sintering, resulting in a dense sintered body. Ta. For comparison, 1 to 10% by weight of catalytic metal powder was mixed with synthetic diamond powder with a relatively low impurity content and heated to graphitize some or all of the diamonds, and then sintered. but,
In this case, it was found that a sufficiently dense sintered body could not be obtained and graphite remained. From this, it can be inferred that the catalytic metal incorporated into the diamond during synthesis and the catalytic metal mixed in later have different effects during sintering. The diamond sintered body produced by the method of this invention is
Because the sintered body contains a catalyst metal, it was thought that the heat resistance would not be sufficiently improved as mentioned above, but the experimental results showed that the heat resistance was significantly improved. It was found that it can withstand heating up to 1000℃. The reason for this is thought to be, firstly, that the metal content is lower than that of the sintered body produced by the conventional method of infiltrating Co, and secondly, the state of distribution of the metal is different. That is, in the sintered body of the present invention, the crystal grains are extremely closely joined to each other, and the catalyst metal exists as spherical or plate-shaped precipitates within the crystal grains rather than at the grain boundaries. On the other hand, in conventional sintered bodies, the catalyst metal exists in the form of a thin film at the interface between diamond particles. This is because the binder phase is Co, which enters into the gaps between the diamond powder during sintering. As a result, in the sintered body of the present invention, the contact area between the metal phase and diamond is relatively small, and it is thought that graphitization of grain boundaries due to heating is less likely to occur, thereby significantly improving heat resistance. In carrying out the present invention, synthetic diamond as a starting material contains 1 to 10% by weight of a catalyst metal or an alloy containing the same in its crystals. Here, the content of the catalyst metal or alloy containing it in the synthetic diamond is set to be in the range of 1 to 10% by weight, because if it is less than 1% by weight, sintering becomes difficult, and
This is because if it exceeds 10% by weight, the heat resistance of the sintered body decreases, which is undesirable. Graphitization of the starting material is necessary to improve sinterability, and is carried out by heating the diamond powder to about 1400° C. or higher in vacuum or in a non-oxidizing atmosphere. Sintering is performed using an ultra-high pressure device such as a belt-type ultra-high pressure device, at a temperature of at least 50 Kb or more and 1400° C. or more. This will be explained in detail below using examples. Example 1 Synthetic diamond powder containing metal impurities shown in Table 1 below and having an average particle size of 25 μm was used as a starting material.
【表】【table】
【表】
上記第1表中の数値は質量分析装置を用いて分
析したダイヤモンド粉末の含有金属量である。
上記の各々の粉末を真空炉中で1400℃に1時間
保持した。取出した粉末の黒鉛化の割合をX線回
折によつて調べたところ、Aで約10%、Bが5
%、Cが1%、Dは0.5%であつた。
これらの粉末を夫々Ta製の容器に密閉し、ベ
ルト型超高圧装置を用いて圧力70Kb、温度1400
℃で5分間保持し焼結した。
その結果、粉末Dを除いて焼結体を回収できた
が、粉末Dのものは充分な焼結体が得られなかつ
た。
そして得られた焼結体のX線回折を行なつたと
ころ粉末A、Bを用いたものは黒鉛の残留は認め
られなかつたが、粉末CおよびDを用いたものは
少量の黒鉛の残留が認められた。
ここで粉末CおよびDはその粒内に含有される
金属量が本発明の範囲よりも少ないため、焼結が
進行し難かつたものと推定される。
次いでA、Bよりなる焼結体を加工して切削チ
ツプを製造し、ビツカース硬度2000のアルミナ焼
結体を切削して性能を評価した。
第2表は比較材として市販のCoを約10%含有
する焼結体と共に工具逃げ面の摩耗幅を示したも
のである。
なお、切削速度 50m/分
切り込み 0.5mm
送り 0.05mm/rpm
切削時間 15分乾式
の条件で切削を行つたものである。[Table] The numerical values in Table 1 above are the amounts of metals contained in the diamond powder analyzed using a mass spectrometer. Each of the above powders was held at 1400° C. for 1 hour in a vacuum furnace. When the graphitization rate of the taken out powder was examined by X-ray diffraction, it was found that A was about 10% and B was about 5%.
%, C was 1%, and D was 0.5%. Each of these powders was sealed in a container made of Ta and heated to a pressure of 70 Kb and a temperature of 1400 using a belt-type ultra-high pressure device.
It was held at ℃ for 5 minutes and sintered. As a result, a sintered body was recovered except for powder D, but a sufficient sintered body of powder D could not be obtained. When the resulting sintered bodies were subjected to X-ray diffraction, no residual graphite was observed in those using powders A and B, but a small amount of graphite remained in those using powders C and D. Admitted. Here, it is presumed that powders C and D had a smaller amount of metal contained within their grains than the range of the present invention, so sintering was difficult to proceed. Next, the sintered bodies of A and B were processed to produce a cutting chip, and the performance was evaluated by cutting an alumina sintered body with a Vickers hardness of 2000. Table 2 shows the wear width of the flank surface of the tool along with a commercially available sintered body containing approximately 10% Co as a comparison material. The cutting was performed under dry conditions with a cutting speed of 50 m/min, a depth of cut of 0.5 mm, a feed rate of 0.05 mm/rpm, and a cutting time of 15 minutes.
【表】
実施例 2
実施例1のA粉末を用い、焼結条件を第3表に
示すように種々かえて実験を行つた。[Table] Example 2 Using powder A of Example 1, experiments were conducted with various sintering conditions as shown in Table 3.
【表】
上表の結果から、No.1で黒鉛が残留するのは圧
力、温度共に不足するためと考えられ、No.5にお
いて黒鉛が残留するのは温度が高すぎてダイヤモ
ンド安定領域から外れるためと考えられる。
次にNo.2〜4の焼結体を用い、加熱テストを行
なつた。
何れも1000℃で30分間の加熱によつても外観、
比重の変化はみられなかつた。
(ニ) 発明の効果
この発明の方法による焼結体は、切削工具、掘
削工具、伸線ダイス、ドレツサー等の工具材料と
してすぐれた耐熱性、耐摩耗性を有しており、特
に従来のダイヤモンド焼結体の欠点であつた耐熱
性が強度を下げることなく大幅に改善されている
ため、工具材としての適用範囲、性能が飛躍的に
向上したのである。[Table] From the results in the table above, it is thought that the reason graphite remains in No. 1 is due to insufficient pressure and temperature, and the reason graphite remains in No. 5 is because the temperature is too high and it is out of the diamond stability region. It is thought that this is because of this. Next, a heating test was conducted using the sintered bodies No. 2 to 4. Even after heating at 1000℃ for 30 minutes, the appearance
No change in specific gravity was observed. (d) Effects of the Invention The sintered body produced by the method of the present invention has excellent heat resistance and wear resistance as a tool material for cutting tools, drilling tools, wire drawing dies, dressers, etc. Heat resistance, which had been a drawback of sintered bodies, has been significantly improved without reducing strength, so the range of application and performance as tool materials has been dramatically improved.
Claims (1)
8族の鉄族金属あるいはCr、Mn、Taもしくは
これらを含む合金からなるダイヤモンド合成触媒
を1〜10重量%含有する合成ダイヤモンド粉末を
ダイヤモンドが不安定な条件下で高温にさらし、
その一部もしくは全部を黒鉛化せしめて原料と
し、これを圧力50Kb以上、1400℃以上の超高圧、
高温下において原料外から原料中へ該ダイヤモン
ド合成触媒が侵入しない状況下で焼結することを
特徴とする硬質焼結体の製造方法。1. Synthetic diamond powder containing 1 to 10% by weight of a diamond synthesis catalyst consisting of an iron group metal of Group 8 of the periodic table, Cr, Mn, Ta, or an alloy containing these used in diamond synthesis, is exposed to high temperatures under conditions,
Part or all of it is graphitized and used as a raw material, which is then processed under ultra-high pressure of over 50Kb and over 1400℃.
A method for producing a hard sintered body, characterized in that sintering is carried out at a high temperature under conditions in which the diamond synthesis catalyst does not enter the raw material from outside the raw material.
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP773784A JPS60152641A (en) | 1984-01-18 | 1984-01-18 | Production of hard sintered body |
US06/688,654 US4610699A (en) | 1984-01-18 | 1985-01-03 | Hard diamond sintered body and the method for producing the same |
ZA85148A ZA85148B (en) | 1984-01-18 | 1985-01-07 | Hard diamond sintered body and the method for producing the same |
DE8585300287T DE3567383D1 (en) | 1984-01-18 | 1985-01-16 | Hard diamond sintered body |
EP85300287A EP0155066B1 (en) | 1984-01-18 | 1985-01-16 | Hard diamond sintered body |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP773784A JPS60152641A (en) | 1984-01-18 | 1984-01-18 | Production of hard sintered body |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS60152641A JPS60152641A (en) | 1985-08-10 |
JPS648688B2 true JPS648688B2 (en) | 1989-02-15 |
Family
ID=11674011
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP773784A Granted JPS60152641A (en) | 1984-01-18 | 1984-01-18 | Production of hard sintered body |
Country Status (2)
Country | Link |
---|---|
JP (1) | JPS60152641A (en) |
ZA (1) | ZA85148B (en) |
-
1984
- 1984-01-18 JP JP773784A patent/JPS60152641A/en active Granted
-
1985
- 1985-01-07 ZA ZA85148A patent/ZA85148B/en unknown
Also Published As
Publication number | Publication date |
---|---|
ZA85148B (en) | 1985-08-28 |
JPS60152641A (en) | 1985-08-10 |
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