JPH0235705B2 - - Google Patents
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- Publication number
- JPH0235705B2 JPH0235705B2 JP59100893A JP10089384A JPH0235705B2 JP H0235705 B2 JPH0235705 B2 JP H0235705B2 JP 59100893 A JP59100893 A JP 59100893A JP 10089384 A JP10089384 A JP 10089384A JP H0235705 B2 JPH0235705 B2 JP H0235705B2
- Authority
- JP
- Japan
- Prior art keywords
- sintering
- ceramics
- group
- ceramic
- synthesis
- 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
- 239000000919 ceramic Substances 0.000 claims description 68
- 238000005245 sintering Methods 0.000 claims description 65
- 239000000843 powder Substances 0.000 claims description 46
- 238000006243 chemical reaction Methods 0.000 claims description 40
- 238000000034 method Methods 0.000 claims description 37
- 238000003786 synthesis reaction Methods 0.000 claims description 30
- 229910052751 metal Inorganic materials 0.000 claims description 29
- 230000015572 biosynthetic process Effects 0.000 claims description 20
- 229910052799 carbon Inorganic materials 0.000 claims description 19
- 239000002184 metal Substances 0.000 claims description 19
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 15
- 230000002194 synthesizing effect Effects 0.000 claims description 15
- 238000010438 heat treatment Methods 0.000 claims description 13
- 239000000203 mixture Substances 0.000 claims description 12
- 229910052755 nonmetal Inorganic materials 0.000 claims description 5
- 238000000280 densification Methods 0.000 claims description 4
- 238000000465 moulding Methods 0.000 claims description 3
- 238000002485 combustion reaction Methods 0.000 claims description 2
- 238000010894 electron beam technology Methods 0.000 claims description 2
- 230000000737 periodic effect Effects 0.000 claims 2
- 239000003085 diluting agent Substances 0.000 claims 1
- 230000006698 induction Effects 0.000 claims 1
- 239000013078 crystal Substances 0.000 description 9
- 238000004519 manufacturing process Methods 0.000 description 9
- 238000012545 processing Methods 0.000 description 9
- 239000002245 particle Substances 0.000 description 7
- 238000007796 conventional method Methods 0.000 description 5
- 230000005611 electricity Effects 0.000 description 4
- 239000011812 mixed powder Substances 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 239000011863 silicon-based powder Substances 0.000 description 4
- 229910003481 amorphous carbon Inorganic materials 0.000 description 3
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 3
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 3
- 229910052753 mercury Inorganic materials 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000009694 cold isostatic pressing Methods 0.000 description 2
- 238000009770 conventional sintering Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- 238000000815 Acheson method Methods 0.000 description 1
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000007596 consolidation process Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004049 embossing Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 230000002706 hydrostatic effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
Landscapes
- Ceramic Products (AREA)
Description
【発明の詳細な説明】
(イ) 技術分野
本発明は、外熱を加えることなく、或は通常の
セラミツクス粉末を焼結する温度よりもはるかに
低い温度で、セラミツクスを焼結する技術に関す
る。この時セラミツクスの焼結に必要なエネルギ
ーは、金属元素と非金属元素を化合させてセラミ
ツクスを合成する際に発生する反応熱によつて供
給され、セラミツクスの合成と焼結が１つの工程
で同時に完了するところに特徴がある。この時合
成時或いは合成中に加圧圧密することによつて焼
結体を緻密化させる方法である。DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to a technique for sintering ceramics without applying external heat or at a temperature much lower than the temperature at which ordinary ceramic powder is sintered. At this time, the energy required for sintering ceramics is supplied by the reaction heat generated when combining metal and nonmetallic elements to synthesize ceramics, and the synthesis and sintering of ceramics can be performed simultaneously in one process. It is characterized by its completion. At this time, this is a method of densifying the sintered body by pressurizing and compacting it during or during the synthesis.
(ロ) 従来技術の問題点
従来緻密なセラミツクス物品を得るためには、
セラミツクスの粉末を合成する工程と、この粉末
を焼結する工程の２つの工程を経ることが必要で
あつた。このため工程が非常に複雑で時間が掛
り、エネルギーのロスも大きかつた。たとえば従
来の方法でSiCの緻密な物品を得ようとする場
合、まず粉末の合成をアチソン法で行うとすると
SiO2粉末とＣ粉末を混合し、この混合物を棒状
に成形した後、この棒状のブロツクを通電加熱し
てSiCを合成し、ブロツクを粉砕してSiCの粉末
を得る。さらに上記のようにして得たSiCの粉末
に焼結助剤を添加して混合し、この混合粉末を所
用の形状に成形した後、高温で焼結して初めて
SiCの緻密な物品が得られる訳である。このよう
に従来法ではセラミツクス粉末を合成する工程と
この粉末を焼結する工程とが別個に存在するため
に、工程が非常に複雑になり、また、粉末合成と
焼結の際に別個に2000℃前後の高温を作り出さな
ければならないため、多大のエネルギーを必要と
する欠点もあつた。(b) Problems with conventional technology In order to obtain dense ceramic articles,
It was necessary to go through two steps: a step of synthesizing ceramic powder and a step of sintering this powder. As a result, the process was extremely complicated and time-consuming, and the loss of energy was large. For example, when trying to obtain a dense SiC article using the conventional method, first synthesize the powder using the Acheson method.
SiO 2 powder and C powder are mixed, this mixture is formed into a rod shape, the rod-shaped block is heated with electricity to synthesize SiC, and the block is pulverized to obtain SiC powder. Furthermore, a sintering aid is added to the SiC powder obtained as described above and mixed, this mixed powder is molded into the desired shape, and then sintered at high temperature.
This means that dense SiC products can be obtained. In this way, in the conventional method, the process of synthesizing ceramic powder and the process of sintering this powder are separate, making the process extremely complicated. It also had the disadvantage of requiring a large amount of energy, as it had to generate a high temperature of around 30°F.
また、一般にセラミツクスを焼結する際には、
焼結時の緻密化を促進する目的で、原料のセラミ
ツクス粉末に焼結助剤を添加して焼結することが
多い。添加する焼結助剤の量の多少は、セラミツ
クスの種類によつてまちまちであるが、添加した
焼結助剤は緻密化を助ける働きはするけれども、
焼結後も粒界などに残留してセラミツクス焼結体
の特性に悪影響を及ぼすことが多い。たとえば
Si3N4の焼結を例にとると、焼結助剤として添加
されたMgOやAl2O3は焼結後もSi3N4の粒界にガ
ラス相として残留し、このため1000℃を越すよう
な高温域では粒界のガラス相が軟化して強度が低
下するという欠点があつた。 Also, generally when sintering ceramics,
In order to promote densification during sintering, a sintering aid is often added to the raw ceramic powder before sintering. The amount of sintering aid added varies depending on the type of ceramics, but although the added sintering aid works to assist in densification,
Even after sintering, it often remains at grain boundaries and has an adverse effect on the properties of the ceramic sintered body. for example
Taking the sintering of Si 3 N 4 as an example, MgO and Al 2 O 3 added as sintering aids remain in the grain boundaries of Si 3 N 4 as a glass phase even after sintering, and therefore In the high temperature range exceeding 1, the glass phase at the grain boundaries softens and the strength decreases.
さらに、セラミツクスの粉末粒子は金属粉末と
違つて塑性変形しないため、高圧下で成形を行つ
ても成形体は理論密度のせいぜい70％以下までし
か緻密化しない。たとえばSiC粉末と鉄粉を同じ
5ton／cm2の圧力で冷間静水圧成形しても、鉄粉成
形体は理論密度の95％まで緻密化できたのに対し
て、SiC粉末の成形体は65％までしか緻密化でき
なかつた。このようにセラミツクスは焼結前の粉
末成形体の密度が低いために、焼結して緻密化さ
せると焼結の前後での寸法差が大きく、焼結体の
寸法精度を精密に制御することが困難である。上
記の成形体密度65％のSiCを常圧焼結してほぼ理
論密度まで緻密化させると、一辺の寸法にして
13.3％もの収縮率になる。このため焼結体の寸法
精度を上げるために焼結後の加工に頼つているの
が現状である。 Furthermore, unlike metal powder, ceramic powder particles do not deform plastically, so even when molded under high pressure, the compact will only be densified to less than 70% of its theoretical density at most. For example, SiC powder and iron powder are the same
Even with cold isostatic pressing at a pressure of 5 ton/ cm2 , the iron powder compact could be densified to 95% of its theoretical density, whereas the SiC powder compact could only be densified to 65%. Ta. In this way, ceramics has a low density as a powder compact before sintering, so when sintered to make it denser, there is a large dimensional difference before and after sintering, so it is necessary to precisely control the dimensional accuracy of the sintered body. is difficult. When the above-mentioned compacted SiC with a density of 65% is sintered under normal pressure and densified to almost the theoretical density, the dimension of one side is
This results in a shrinkage rate of 13.3%. For this reason, the current situation is to rely on processing after sintering to improve the dimensional accuracy of the sintered body.
またセラミツクスの加工について述べると、セ
ラミツクスの焼結体は一般に金属に比べて非常に
硬度が高く、ダイヤモンド砥石による研削加工に
頼つているのが現状であり、セラミツクスを焼結
した後複雑な形状に加工するのは至難の業であ
る。このため複雑形状のセラミツクス物品を得よ
うとする際には、焼結前に所用の形状に加工を完
了しておく必要がある。この場合でも、セラミツ
クスの粉末成形体の加工が難しく、セラミツクス
粉末が硬いために整形に使用する工具の寿命が極
端に短いなど数多くの問題が存在する。 Regarding the processing of ceramics, sintered ceramics are generally much harder than metals, and currently rely on grinding with a diamond grindstone. Processing it is extremely difficult. Therefore, when attempting to obtain a ceramic article with a complex shape, it is necessary to complete processing into the desired shape before sintering. Even in this case, there are many problems such as it is difficult to process the ceramic powder compact, and the life of the tools used for shaping is extremely short because the ceramic powder is hard.
以上述べたように従来のセラミツクス物品の製
造方法では、まずセラミツクス粉末を合成する工
程から始まつて、焼結工程、加工工程まで非常に
数多くの工程を経なければならず、時間が掛る上
にエネルギーのロスも大きい。焼結を助ける目的
が添加した焼結助剤がセラミツクス本来の特性を
損うことが多い。セラミツクス粉末の成形体は密
度を十分に上げることができないため、焼結時の
収縮率が大きく寸法精度を精密に制御するのが難
しい。セラミツクスは粉末成形体、焼結体にかか
わらず加工が難しい、など数多くの問題があつ
た。 As mentioned above, the conventional manufacturing method for ceramic products requires a large number of steps, starting with the synthesis of ceramic powder, sintering, and processing, which is time consuming and time consuming. Energy loss is also large. Sintering aids added to aid sintering often impair the original properties of ceramics. Since the density of ceramic powder compacts cannot be increased sufficiently, the shrinkage rate during sintering is large, making it difficult to precisely control dimensional accuracy. Ceramics had many problems, such as being difficult to process, regardless of whether it was a powder compact or a sintered product.
本発明者らは、これらの問題を解決し、簡単な
方法でしかもセラミツクス本来の特性を損うこと
なく緻密なセラミツクス物品を得る方法について
研究を重ねた結果、本発明に到つたものである。 The present inventors have arrived at the present invention as a result of repeated research into a method for solving these problems and obtaining dense ceramic articles in a simple manner without impairing the inherent characteristics of ceramics.
(ハ) 発明の開示
本発明が従来の焼結方法と最も大きく異なる点
は、金属元素と非金属元素からセラミツクスを合
成する際の発熱反応を利用して、外熱を全く加え
ないか或は通常の焼結温度よりもはるかに低温に
加熱するだけで、セラミツクスを合成すると同時
に緻密な焼結体を得ることが可能なことである。(C) Disclosure of the Invention The biggest difference between the present invention and conventional sintering methods is that it utilizes the exothermic reaction when synthesizing ceramics from metal elements and non-metallic elements, and either does not apply external heat at all or It is possible to synthesize ceramics and simultaneously obtain a dense sintered body by simply heating the material to a temperature far lower than the normal sintering temperature.
例えばTiとＣからTiCを合成する反応を考える
と、
Ti＋Ｃ→TiC＋55.3Kcal／mol（298〓）………(1)
(1)式に示すようにTiCの生成に伴つて
55.3Kcal／molの反応熱が発生する。このため、
TiとＣの粉末混合物を緻密に成形した物の１部
分を加熱点火し、強制的に(1)式の反応を開始させ
ると、あとは発生する反応熱によつて隣接する部
分が順次反応を開始し、粉末成形体全体へと連鎖
的に反応が進行し、セラミツクスの合成と焼結が
同時に完了する。 For example, considering the reaction of synthesizing TiC from Ti and C, Ti+C→TiC+55.3Kcal/mol (298〓)...(1) As shown in equation (1), as TiC is produced,
A heat of reaction of 55.3 Kcal/mol is generated. For this reason,
When one part of a densely molded Ti and C powder mixture is heated and ignited to force the reaction of equation (1) to start, the reaction heat generated will cause adjacent parts to react one after another. The reaction starts and progresses in a chain reaction throughout the powder compact, and the synthesis and sintering of the ceramics are completed at the same time.
このため本発明によれば従来のセラミツクス粉
末の合成と焼結を別々の工程で行う方法に比べ
て、非常に簡便にセラミツクスの緻密な焼結体を
得ることができる。SiCの合成同時焼結を例にと
つて、従来法の工程と比較したものを第１図に示
す。 Therefore, according to the present invention, a dense sintered body of ceramics can be obtained much more easily than the conventional method of synthesizing ceramic powder and sintering it in separate steps. Taking the simultaneous synthesis and sintering of SiC as an example, Figure 1 shows a comparison with the conventional process.
また従来法でセラミツクスを焼結するために
は、雰囲気を制御しながら1500℃〜2000℃前後の
高温を作り出せるような特殊な電気炉が必要であ
つたが、本発明の合成同時焼結法を用いると、セ
ラミツクスの焼結に必要なエネルギーの大半はセ
ラミツクスを合成する際に発生する反応熱によつ
て供給されるため、雰囲気を制御するための容器
と、合成反応を開始させる点火装置さえあればよ
く、加熱機構が不要なため、焼結に必要な装置面
でも非常に簡単になる。また金属元素を非金属元
素の組合せによつては、合成の際に発生する反応
熱量が小さく、合成反応が連鎖的に進行するのが
困難な系もあり、このような系では成形体を予熱
することが必要であるが、この場合でも従来の焼
結温度に比べればはるかに低い温度で十分であ
る。省エネルギーという観点から考えても、本発
明の合成同時焼結は画期的なものと言える。合成
同時焼結によつて緻密な焼結体を得る方法には２
通りある。１つは高圧発生装置の中で高圧力をか
けながら点火し、圧密の助けを借りて合成同時焼
結するものである。この時の加圧の方法として
は、一軸加圧、等方静水圧加圧のいずれを用いて
もよい。もう一つの方法は、焼結前に一軸加圧や
等方静水圧加圧を用いて高圧力で圧密した後、点
火して合成同時焼結するものである。金属元素と
非金属元素の混合物を高圧下で圧密すると、粉末
自体が塑性変形するためあらかじめ90％以上の密
度まで緻密化させることも可能である。このため
合成同時焼結した際の寸法変化が小さく、焼結体
の寸法精度を精密に制御することが容易である。 Furthermore, in order to sinter ceramics using the conventional method, a special electric furnace that can generate high temperatures of around 1500℃ to 2000℃ while controlling the atmosphere was required, but with the simultaneous synthesis and sintering method of the present invention. When using ceramics, most of the energy required for sintering ceramics is supplied by the reaction heat generated during ceramic synthesis, so all that is needed is a container to control the atmosphere and an igniter to start the synthesis reaction. Since there is no need for a heating mechanism, the equipment required for sintering is also very simple. Furthermore, depending on the combination of metallic elements and non-metallic elements, there are systems in which the amount of reaction heat generated during synthesis is small, making it difficult for the synthesis reaction to proceed in a chain manner. However, even in this case, a temperature much lower than the conventional sintering temperature is sufficient. Even from the viewpoint of energy saving, the simultaneous synthesis and sintering of the present invention can be said to be revolutionary. There are two methods for obtaining a dense sintered body through simultaneous synthesis and sintering.
There is a street. One is to ignite the material while applying high pressure in a high-pressure generator, and perform synthesis and simultaneous sintering with the aid of consolidation. As the pressurization method at this time, either uniaxial pressurization or isostatic hydrostatic pressurization may be used. Another method is to consolidate at high pressure using uniaxial pressure or isostatic isostatic pressure before sintering, and then ignite to perform synthesis and simultaneous sintering. When a mixture of metallic and nonmetallic elements is compacted under high pressure, the powder itself undergoes plastic deformation, making it possible to densify it to a density of 90% or more in advance. Therefore, dimensional changes during simultaneous synthesis and sintering are small, and it is easy to precisely control the dimensional accuracy of the sintered body.
これに対してセラミツクス粉末を焼結する場合
には、粉末成形体の密度が、せいぜい70％以下ま
でしか上げられないので収縮率が大きく、寸法精
度の精密な制御が困難である。 On the other hand, when ceramic powder is sintered, the density of the powder compact can only be increased to 70% or less at most, so the shrinkage rate is large and precise control of dimensional accuracy is difficult.
また、複数形状のセラミツクス物品を得るた
め、焼結前に粉末成形体を所用の形状に加工する
場合でも、セラミツクス粉末の場合と違つて、金
属元素と非金属元素の混合物の粉末成形体は緻密
で軟かいため加工が容易であり、複雑形状の物品
を精度良く加工することができる。整形に使用す
る工具も通常の金属の加工と同様の使用が可能で
ある。 Furthermore, even when processing a powder compact into the desired shape before sintering in order to obtain ceramic articles with multiple shapes, unlike the case of ceramic powder, the powder compact of a mixture of metallic and nonmetallic elements is dense. Because it is soft, it is easy to process, and products with complex shapes can be processed with high precision. The tools used for shaping can also be used in the same way as for normal metal processing.
このように本発明では、焼結前の粉末成形体の
加工に関して大巾な改良がなされている。 As described above, in the present invention, significant improvements have been made in processing the powder compact before sintering.
また本発明では、金属元素と非金属元素を化合
させてセラミツクスを合成すると同時に直接焼結
体を得るので、本質的に緻密化のための焼結助剤
は必要ない。このため高純度で緻密なセラミツク
ス焼結体を得ることができ、セラミツクス本来の
特性を損うことなく発揮させることができる。ま
た不純物の混入をきらうような用途に使用するセ
ラミツクスには最適の焼結法である。 Furthermore, in the present invention, a sintered body is directly obtained at the same time as the ceramic is synthesized by combining a metal element and a nonmetal element, so a sintering aid for densification is not essentially required. Therefore, a highly pure and dense ceramic sintered body can be obtained, and the original characteristics of ceramics can be exhibited without impairing them. It is also the most suitable sintering method for ceramics used in applications where contamination with impurities is a concern.
金属元素と非金属元素の混合物を成形した後、
この成形体の一部に強制点火してセラミツクスの
合成反応を開始させる際に、点火する部位と面積
を変化させることによつて焼結体の結晶粒子の形
状を制御することができる。例えば、第２図イに
示すように１点点火の場合には合成同時焼結が一
方向に進行するため、焼結体の結晶粒子は方向性
を持つたものとなるが、ロに示すような多点点火
を行うと、焼結体中央部の結晶粒子は等方的で均
一なものになる。多点点火によつて作製した
TiB2焼結体の中央部の破面組織を第３図に示す。
写真から分かるように結晶粒子には方向性がな
く、等方的で均一微細な組織になつている。 After forming the mixture of metal and non-metal elements,
When a part of the molded body is forcibly ignited to start a ceramics synthesis reaction, the shape of the crystal grains of the sintered body can be controlled by changing the ignition site and area. For example, in the case of one-point ignition, as shown in Figure 2A, simultaneous synthesis and sintering progresses in one direction, so the crystal grains of the sintered body have directionality, but as shown in Figure 2B, When multi-point ignition is performed, the crystal grains in the center of the sintered body become isotropic and uniform. Produced by multi-point ignition
Figure 3 shows the fracture surface structure at the center of the TiB 2 sintered body.
As you can see from the photo, the crystal grains have no directionality and have an isotropic, uniform, fine structure.
点火の際にカーボンヒーターを用いると、点火
面積、点火形状を任意に変化させることができ、
複雑形状物品を均一に焼結するのに非常に有利で
ある。この他にも、高周波誘電加熱、電子ビーム
による加熱、レーザーによる加熱、助燃剤による
加熱などを使用して点火することができる。 If a carbon heater is used for ignition, the ignition area and shape can be changed arbitrarily.
It is very advantageous for uniformly sintering complex shaped articles. In addition, high-frequency dielectric heating, heating with an electron beam, heating with a laser, heating with a combustion improver, and the like can be used for ignition.
また点火面積と焼結の際の加圧圧力によつて焼
結体の結晶粒子径を制御することができる。合成
同時焼結時に加える圧力が大きい程、結晶粒子の
成長、粗大化が抑制され、均一で微細な結晶粒子
からなる緻密な焼結体が得られる。 Further, the crystal grain size of the sintered body can be controlled by the ignition area and the pressure applied during sintering. The greater the pressure applied during synthesis and simultaneous sintering, the more the growth and coarsening of crystal grains is suppressed, and a dense sintered body made of uniform and fine crystal grains can be obtained.
金属元素と非金属元素を化合させてセラミツク
スを合成する際に発生する反応熱が大きすぎる
と、焼結温度が制御できず爆発的に反応が進行し
て4000℃近くの超高温に達することがある。この
ような焼結体では、セラミツクスの分解、蒸発や
結晶粒子の異常粒成長が起こつて、内部に多くの
欠陥を含んだものとなる。そのため、セラミツク
スの生成反応熱が大きい系に対しては、合成され
るセラミツクスと同一のセラミツクス粉末、或は
合成されるセラミツクスとは異なる種類のセラミ
ツクス粉末を添加し、合成反応を希釈して発生す
る反応熱を制御しながら焼結を進行させることに
より、均一微細な結晶粒子からなる緻密な焼結体
が得られるようになつた。 If the reaction heat generated when combining metal and non-metal elements to synthesize ceramics is too large, the sintering temperature cannot be controlled and the reaction proceeds explosively, reaching extremely high temperatures of nearly 4000℃. be. In such a sintered body, decomposition and evaporation of the ceramics and abnormal growth of crystal grains occur, resulting in many internal defects. Therefore, for systems where the heat of the ceramic formation reaction is large, the synthesis reaction can be diluted by adding ceramic powder that is the same as the ceramic to be synthesized or a ceramic powder of a different type from the ceramic to be synthesized. By proceeding with sintering while controlling the reaction heat, it has become possible to obtain a dense sintered body consisting of uniform, fine crystal grains.
以下、本発明を実施例によつて説明する。 Hereinafter, the present invention will be explained with reference to Examples.
実施例 １
−325メツシユの金属Ti粉末47.90ｇ（１モル）
と平均粒径1.0μｍのＢ粉末21.62ｇ（２モル）を
混合した後、Mo製の密封容器に真空封入した。
この密封容器には点火装置としてカーボンヒータ
ーが組込まれており、リード線が容器の外に取り
出されている。この密封容器を高圧発生装置内に
置き、2000気圧のArガスで加圧しながら、カー
ボンヒーターに通電して点火した。電流はTiB2
の生成反応が開始すると直ちに遮断した。Example 1 -47.90g (1 mol) of metallic Ti powder of 325 mesh
After mixing 21.62 g (2 moles) of B powder with an average particle size of 1.0 μm, the mixture was vacuum-sealed in a sealed container made of Mo.
A carbon heater is built into this sealed container as an ignition device, and a lead wire is taken out of the container. This sealed container was placed in a high-pressure generator, and while pressurized with Ar gas at 2000 atmospheres, electricity was applied to the carbon heater to ignite it. Current is TiB 2
As soon as the production reaction started, it was immediately shut off.
上記のようにして得られたTiB2の焼結体は、
密度99.3％、TiB2へ転換率99％以上であつた。 The TiB 2 sintered body obtained as above is
The density was 99.3% and the conversion rate to TiB 2 was over 99%.
実施例 ２
−325メツシユの金属Zr粉末91.22ｇ（１モル）
と、平均粒径1.0μｍのＢ粉末21.62ｇ（２モル）
を混合した後、直径40mmの金型プレスを用いて、
5ton／cm2の圧力で型押成形した。この円柱成形体
の１部分を切断し、水銀圧入法で空隙率を調べた
ところ9.3％であつた。残りの円柱成形体を反応
容器内に置き、円柱の上下面にカーボンヒーター
を接触させた。反応容器内をArガスで置換した
後、カーボンヒーターに通電して点火した。電流
はZrB2の生成反応が開始すると直ちに遮断した。Example 2 -91.22g (1 mol) of metal Zr powder of 325 mesh
and 21.62 g (2 moles) of B powder with an average particle size of 1.0 μm.
After mixing, using a mold press with a diameter of 40 mm,
Embossing was carried out at a pressure of 5 ton/cm 2 . A portion of this cylindrical molded body was cut and the porosity was examined by mercury intrusion method and found to be 9.3%. The remaining cylindrical molded body was placed in a reaction vessel, and carbon heaters were brought into contact with the upper and lower surfaces of the cylinder. After replacing the inside of the reaction vessel with Ar gas, electricity was applied to the carbon heater to ignite it. The current was interrupted immediately after the ZrB 2 production reaction started.
上記のようにして得られたZrB2の焼結体は、
密度90.5％、ZrB2への転換率99％以上であつた。 The ZrB 2 sintered body obtained as above is
The density was 90.5% and the conversion rate to ZrB 2 was over 99%.
実施例 ３
−325メツシユの金属Ti粉末47.90ｇ（１モル）
と、平均粒径100Åのアモルフアスカーボン12.01
ｇ（１モル）を混合した後、混合粉末の一部を金
型プレスを用いて2ton／cm2の圧力で、直径６mm高
さ６mmの円柱状に成形した。この円柱成形体を
BN製容器の中に納め、成形体の上端面をカーボ
ンヒーターに接触させた後、超高圧発生装置内に
置き、30000Kg／cm2の圧力で加圧しながら、カー
ボンヒーターに通電して点火した。電流はTiCの
生成反応が開始すると直ちに遮断した。Example 3 -47.90g (1 mol) of metallic Ti powder of 325 mesh
and amorphous carbon 12.01 with an average particle size of 100 Å.
g (1 mol), a part of the mixed powder was molded into a cylinder having a diameter of 6 mm and a height of 6 mm using a die press at a pressure of 2 tons/cm 2 . This cylindrical molded body
The molded body was placed in a BN container, and the upper end surface of the molded body was brought into contact with a carbon heater, and then placed in an ultra-high pressure generator, and while pressurized at a pressure of 30,000 Kg/cm 2 , electricity was applied to the carbon heater to ignite it. The current was interrupted immediately after the TiC production reaction started.
上記のようにして得られたTiCの焼結体は密度
99.7％、TiCへの転換率99％以上であつた。 The TiC sintered body obtained as described above has a density of
The conversion rate to TiC was 99.7% or more.
実施例 ４
−325メツシユの金属Si粉末28.09ｇ（１モル）
と、平均粒径100Åのアモルフアスカーボン12.01
ｇ（１モル）を混合した後、CIP装置を用いてこ
の混合粉末を6ton／cm2の圧力で直径15mmの円柱に
成形した。この円柱成形体の１部分を切断し、水
銀圧入法で空隙率を調べた際に水銀が全く侵入し
なかつた。このことから考えてこの円柱成形体の
空隙率は５％以下であると考えられる。残りの円
柱成形体を反応容器内に置き、反応容器内を１×
10-5torr前後の真空にした後、反応容器内を800
℃に予熱しながら、円柱の上端面をレーザーによ
つて加熱して点火した。レーザーはSiCの生成反
応が開始すると直ちに遮断した。Example 4 -28.09g (1 mol) of metal Si powder of 325 mesh
and amorphous carbon 12.01 with an average particle size of 100 Å.
g (1 mol), the mixed powder was molded into a cylinder with a diameter of 15 mm at a pressure of 6 tons/cm 2 using a CIP device. When a portion of this cylindrical molded body was cut and the porosity was examined by mercury intrusion method, no mercury had penetrated into it at all. Considering this, it is considered that the porosity of this cylindrical molded body is 5% or less. Place the remaining cylindrical molded body in the reaction container, and make the inside of the reaction container 1×
After creating a vacuum of around 10 -5 torr, the inside of the reaction vessel was heated to 800
While preheating to ℃, the upper end surface of the cylinder was heated with a laser and ignited. The laser was shut off immediately after the SiC production reaction started.
上記のようにして得られたSiCの焼結体は、密
度95.6％、SiCへの転換率97％であつた。 The SiC sintered body obtained as described above had a density of 95.6% and a conversion rate to SiC of 97%.
実施例 ５
−325メツシユの金属Ｗ粉末183.85ｇ（１モル）
と、平均粒径100Åのアモルフアスカーボン12.01
ｇ（１モル）を混合した後、Ｗ製の密封容器に真
空封入した。この密封容器には点火装置としてカ
ーボンヒーターが組込まれており、リード線が容
器の外に取り出されている。この密封容器を高圧
発生装置内に置き、密封容器を800℃に予熱し、
2000気圧のArガスで加圧しながら、カーボンヒ
ーターに通電して点火した。電流はWCの生成反
応が開始すると直ちに遮断した。Example 5 -325 mesh metal W powder 183.85g (1 mol)
and amorphous carbon 12.01 with an average particle size of 100 Å.
g (1 mol) was mixed, and the mixture was vacuum sealed in a sealed container made of W. A carbon heater is built into this sealed container as an ignition device, and a lead wire is taken out of the container. Place this sealed container in a high pressure generator, preheat the sealed container to 800℃,
The carbon heater was ignited by energizing it while pressurizing with Ar gas at 2000 atm. The current was interrupted immediately after the WC production reaction started.
上記のようにして得られたWCの焼結体は、密
度98.6％、WCへの転換率97％であつた。 The sintered body of WC obtained as described above had a density of 98.6% and a conversion rate to WC of 97%.
実施例 ６
−325メツシユの金属Al粉末26.98ｇ（１モル）
を、直径60mmの金型プレスを用いて2ton／cm2の圧
力で型押成形した。この円板成形体は理論密度の
91.2％の密度であつた。この円板成形体を高圧発
生装置内に置き、円板上面の一端にカーボンヒー
ターを接触させた。高圧発生装置内に1500気圧の
N2ガスを充填した後、ヒーターに通電して点火
した。電流はAlNの生成反応が開始すると直ち
に遮断した。Example 6 -26.98g (1 mol) of metal Al powder of 325 mesh
was molded using a mold press with a diameter of 60 mm at a pressure of 2 tons/cm 2 . This disk compact has a theoretical density of
The density was 91.2%. This disc molded body was placed in a high pressure generator, and a carbon heater was brought into contact with one end of the disc's upper surface. 1500 atm inside the high pressure generator
After filling with N2 gas, the heater was energized and ignited. The current was interrupted immediately after the AlN production reaction started.
上記のようにして得られたAlNの焼結体は、
密度92.3％、AlNへの転換率93％であつた。 The AlN sintered body obtained as above is
The density was 92.3% and the conversion rate to AlN was 93%.
実施例 ７
−325メツシユの金属Si粉末28.09ｇ（１モル）
に、Si3N4の合成反応を希釈して発生する反応熱
を制御しながら焼結を進行させる目的で、平均粒
径1μｍのSi3N4粉末14.03ｇ（0.1モル）を添加し
混合した。この混合粉末を直径60mmの金型プレス
を用いて2ton／cm2の圧力で型押成形した。この円
板成形体は理論密度90.3％の密度であつた。この
円板成形体を高圧発生装置内に置き、円板上面の
一端にカーボンヒーターを接触させた。高圧発生
装置内に1500気圧のN2ガスを充填した後、ヒー
ターに通電して点火した。電流はSi3N4の生成反
応が開始すると直ちに遮断した。Example 7 -28.09g (1 mol) of metal Si powder of 325 mesh
To this, 14.03 g (0.1 mol) of Si 3 N 4 powder with an average particle size of 1 μm was added and mixed in order to dilute the Si 3 N 4 synthesis reaction and proceed with sintering while controlling the reaction heat generated. . This mixed powder was pressed and molded using a die press with a diameter of 60 mm at a pressure of 2 tons/cm 2 . This disk compact had a density of 90.3% of the theoretical density. This disc molded body was placed in a high pressure generator, and a carbon heater was brought into contact with one end of the disc's upper surface. After filling the high-pressure generator with 1500 atmospheres of N 2 gas, the heater was energized and ignited. The current was interrupted as soon as the Si 3 N 4 production reaction started.
上記のようにして得られたSi3N4の焼結体は密
度93.1％、Si3N4への転換率95％であつた。 The Si 3 N 4 sintered body obtained as described above had a density of 93.1% and a conversion rate to Si 3 N 4 of 95%.
実施例 ８
−325メツシユの金属Ta粉末180.95ｇ（１モ
ル）と、−325メツシユの金属Si粉末56.17ｇ（２
モル）と混合した後、Ta製の密封容器に真空封
入した。この密封容器には点火装置としてカーボ
ンヒーターが組込まれており、リード線が容器の
外に取り出されている。この密封容器を高圧発生
装置内に置き、密封容器を600℃に予熱して、
2000気圧のArガスで加圧しながら、カーボンヒ
ーターに通電して点火した。電流はWCの生成反
応が開始すると直ちに遮断した。Example 8 180.95 g (1 mol) of -325 mesh metal Ta powder and 56.17 g (2 mol) of -325 mesh metal Si powder
mol) and then vacuum sealed in a Ta sealed container. A carbon heater is built into this sealed container as an ignition device, and a lead wire is taken out of the container. Place this sealed container in a high pressure generator, preheat the sealed container to 600℃,
The carbon heater was ignited by energizing it while pressurizing with Ar gas at 2000 atm. The current was interrupted immediately after the WC production reaction started.
上記のようにして得られたTaSi2の焼結体は密
度97.2％、TaSi2への転換率96％であつた。 The TaSi 2 sintered body obtained as described above had a density of 97.2% and a conversion rate to TaSi 2 of 96%.
第１図は本発明の方法イと従来の方法ロの工程
図、第２図は本発明の反応開始のための点火方法
を説明する図でイが１点点火法、ロが多点点火法
を示し、第３図は本発明の方法で作製したTiB2
焼結体の中央部の粒子構造の顕微鏡写真（1200倍
拡大図）である。
１：Si粉末、２：Ｃ粉末、３：混合、４：高圧
成型、５：成型、６：合成同時焼結、７：高圧下
合成同時焼結、８：SiC緻密質焼結体、９：加
熱、１０：粉砕、１１：焼結助剤添加混合、１
２：焼結、１３：加工、１４：カーボンヒータ
ー、Ａ：粉末合成工程、Ｂ：焼結工程、Ｍ：混合
物成型体。
Fig. 1 is a process diagram of method A of the present invention and conventional method B, and Fig. 2 is a diagram explaining the ignition method for starting the reaction of the present invention, in which A is the one-point ignition method and B is the multi-point ignition method. Figure 3 shows TiB 2 produced by the method of the present invention.
This is a micrograph (1200x magnification) of the grain structure in the center of the sintered body. 1: Si powder, 2: C powder, 3: Mixing, 4: High pressure molding, 5: Molding, 6: Synthesis and simultaneous sintering, 7: Synthesis and simultaneous sintering under high pressure, 8: SiC dense sintered body, 9: Heating, 10: Grinding, 11: Sintering aid addition and mixing, 1
2: Sintering, 13: Processing, 14: Carbon heater, A: Powder synthesis process, B: Sintering process, M: Mixture molded body.
Claims (1)
際に発生する反応熱を利用して、外熱を加えるこ
となく、あるいは通常の焼結温度よりはるかに低
い温度で予熱してセラミツクの合成と焼結を行う
ことを特徴とするセラミツクスの合成同時焼結
法。 ２ 金属元素が周期律表第、第ａ、第ａ及
び第ａ族から選ばれた少くとも１種の元素であ
り、非金属元素がＢ，Ｃ，Ｎ，Siからなる群から
選ばれた少くとも１種の元素であることを特徴と
する特許請求の範囲第１項記載のセラミツクスの
合成同時焼結法。 ３ 金属元素と非金属元素の混合物に、合成され
るセラミツクスと同一のセラミツクス粉末、或は
合成されるセラミツクスとは異なる種類のセラミ
ツクス粉末を、合成反応の希釈剤として添加する
ことによつて、セラミツクスの合成反応が進行す
る速度を制御しながら焼結することを特徴とする
特許請求の範囲第１項記載のセラミツクスの合成
同時焼結方法。 ４ 金属元素と非金属元素の混合物を成形した
後、この成形体の一部を加熱してセラミツクスの
合成反応を開始させ、この時発生する反応熱によ
つて隣接する部分の合成反応を誘起し、順次成形
体全体までセラミツクス化しながら焼結すること
を特徴とする特許請求の範囲第１項記載のセラミ
ツクスの合成同時焼結方法。 ５ 特許請求の範囲第４項記載の合成反応開始の
ための加熱方法がカーボンヒーターを用いた通電
加熱、電子ビームによる加熱、高周波誘導加熱、
レーザーによる加熱、助燃剤による加熱のいずれ
かであることを特徴とするセラミツクスの合成同
時焼結方法。 ６ 金属元素と非金属元素の混合物からセラミツ
クスを合成する時に発生する反応熱を利用して焼
結を行う際に、高圧力下で合成させることによ
り、焼結体の緻密化を促進することを特徴とする
セラミツクスの合成同時焼結方法。 ７ 金属元素と非金属元素の混合物を高圧力下で
圧密体の空隙率が30％以下になるまで圧密した
後、セラミツクスの合成時に発生する反応熱を利
用して焼結を行うことを特徴とする特許請求の範
囲第６項記載のセラミツクスの合成同時焼結方
法。 ８ 金属元素が周期律表第族、第ａ族、第
ａ族および第ａ族から選ばれた少なくとも１種
の金属元素と、Ｂ，Ｃ，Ｎ，Siからなる群より選
ばれた少くとも１種の元素であることを特徴とす
る特許請求の範囲第６項記載のセラミツクスの合
成同時焼結方法。[Claims] 1. Preheating without applying external heat or at a temperature far lower than the normal sintering temperature by using the reaction heat generated when synthesizing a metal element and a non-metal element. A method for simultaneously synthesizing and sintering ceramics, which is characterized by synthesizing and sintering ceramics. 2. The metallic element is at least one element selected from Group A, Group A, and Group A of the Periodic Table, and the nonmetallic element is at least one element selected from the group consisting of B, C, N, and Si. The method for simultaneously synthesizing and sintering ceramics according to claim 1, wherein both elements are one type of element. 3. Ceramics can be produced by adding ceramic powder of the same type as the ceramic to be synthesized or a ceramic powder of a different type from the ceramic to be synthesized as a diluent in the synthesis reaction to a mixture of metallic elements and non-metallic elements. 2. The method for simultaneously synthesizing and sintering ceramics according to claim 1, wherein the sintering is carried out while controlling the rate at which the synthesis reaction proceeds. 4. After molding a mixture of metal elements and non-metallic elements, a part of this molded body is heated to initiate a ceramic synthesis reaction, and the reaction heat generated at this time induces a synthesis reaction in adjacent parts. 2. The method for simultaneously synthesizing and sintering ceramics according to claim 1, wherein the entire molded body is sintered while being turned into a ceramic. 5. The heating method for starting the synthesis reaction described in claim 4 includes electrical heating using a carbon heater, heating using an electron beam, high-frequency induction heating,
A method for simultaneously synthesizing and sintering ceramics, characterized by heating with a laser or heating with a combustion improver. 6. When performing sintering using the reaction heat generated when ceramics are synthesized from a mixture of metal and non-metal elements, it is possible to promote the densification of the sintered body by performing the synthesis under high pressure. Features a method for simultaneously synthesizing and sintering ceramics. 7. A mixture of metallic and non-metallic elements is compacted under high pressure until the porosity of the compact becomes 30% or less, and then sintered using the reaction heat generated during the synthesis of ceramics. A method for simultaneously synthesizing and sintering ceramics according to claim 6. 8 The metal element is at least one metal element selected from Group A, Group A, Group A, and Group A of the Periodic Table, and at least one metal element selected from the group consisting of B, C, N, and Si. 7. The method for simultaneously synthesizing and sintering ceramics according to claim 6, wherein said element is a seed element.
Priority Applications (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59100893A JPS60246270A (en) | 1984-05-18 | 1984-05-18 | Ceramic simultaneously synthesizing and sintering process |
| EP91102739A EP0435854B1 (en) | 1984-05-18 | 1985-05-17 | Method of sintering metal-dispersed reinforced ceramics |
| DE8585303474T DE3584475D1 (en) | 1984-05-18 | 1985-05-17 | METHOD FOR SINTERING CERAMIC BODIES AND CERAMIC BODIES PRODUCED BY SAME WITH A DISTRIBUTED METAL REINFORCEMENT. |
| EP85303474A EP0165707B1 (en) | 1984-05-18 | 1985-05-17 | Method of sintering ceramics and metal-dispersed reinforced ceramics obtained thereby |
| DE3588005T DE3588005T2 (en) | 1984-05-18 | 1985-05-17 | Process for sintering ceramic bodies with a distributed metal reinforcement. |
| US07/158,115 US4906295A (en) | 1984-05-18 | 1988-02-16 | Dispersed reinforced ceramics |
| US07/392,287 US4965044A (en) | 1984-05-18 | 1989-08-11 | Method of sintering ceramics and metal dispersed reinforced ceramics obtained thereby |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59100893A JPS60246270A (en) | 1984-05-18 | 1984-05-18 | Ceramic simultaneously synthesizing and sintering process |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60246270A JPS60246270A (en) | 1985-12-05 |
| JPH0235705B2 true JPH0235705B2 (en) | 1990-08-13 |
Family
ID=14286012
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59100893A Granted JPS60246270A (en) | 1984-05-18 | 1984-05-18 | Ceramic simultaneously synthesizing and sintering process |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60246270A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4889745A (en) * | 1986-11-28 | 1989-12-26 | Japan As Represented By Director General Of Agency Of Industrial Science And Technology | Method for reactive preparation of a shaped body of inorganic compound of metal |
| JPH10101433A (en) * | 1996-09-30 | 1998-04-21 | Kagaku Gijutsu Shinko Jigyodan | Titanium boride-silicon carbide-based complex ceramic |
| JP2018135223A (en) * | 2017-02-20 | 2018-08-30 | 一般財団法人ファインセラミックスセンター | Production method of ceramic composite material and production method of ceramic member |
| JP2018135224A (en) * | 2017-02-20 | 2018-08-30 | 一般財団法人ファインセラミックスセンター | Production method of silicon carbide sintered body |
-
1984
- 1984-05-18 JP JP59100893A patent/JPS60246270A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60246270A (en) | 1985-12-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |