JPH0346432B2 - - Google Patents
Info
- Publication number
- JPH0346432B2 JPH0346432B2 JP11645983A JP11645983A JPH0346432B2 JP H0346432 B2 JPH0346432 B2 JP H0346432B2 JP 11645983 A JP11645983 A JP 11645983A JP 11645983 A JP11645983 A JP 11645983A JP H0346432 B2 JPH0346432 B2 JP H0346432B2
- Authority
- JP
- Japan
- Prior art keywords
- barium titanate
- hollandite
- mixture
- general formula
- tio
- 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
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- JRPBQTZRNDNNOP-UHFFFAOYSA-N barium titanate Chemical compound [Ba+2].[Ba+2].[O-][Ti]([O-])([O-])[O-] JRPBQTZRNDNNOP-UHFFFAOYSA-N 0.000 claims description 20
- 229910002113 barium titanate Inorganic materials 0.000 claims description 20
- 239000013078 crystal Substances 0.000 claims description 15
- 238000004519 manufacturing process Methods 0.000 claims description 13
- 239000000203 mixture Substances 0.000 claims description 13
- 239000000155 melt Substances 0.000 claims description 9
- 239000002994 raw material Substances 0.000 claims description 9
- 229910052723 transition metal Inorganic materials 0.000 claims description 9
- 150000003624 transition metals Chemical class 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 8
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 7
- 229910052782 aluminium Inorganic materials 0.000 claims description 6
- 229910052804 chromium Inorganic materials 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 6
- 238000002844 melting Methods 0.000 claims description 6
- 230000008018 melting Effects 0.000 claims description 6
- 150000001875 compounds Chemical class 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 5
- 238000001816 cooling Methods 0.000 claims description 4
- MEFBJEMVZONFCJ-UHFFFAOYSA-N molybdate Chemical compound [O-][Mo]([O-])(=O)=O MEFBJEMVZONFCJ-UHFFFAOYSA-N 0.000 claims description 4
- 239000006104 solid solution Substances 0.000 claims description 4
- 229910052733 gallium Inorganic materials 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 3
- 150000003839 salts Chemical class 0.000 claims description 3
- 238000010583 slow cooling Methods 0.000 claims description 3
- 238000001704 evaporation Methods 0.000 claims description 2
- QVQLCTNNEUAWMS-UHFFFAOYSA-N barium oxide Chemical compound [Ba]=O QVQLCTNNEUAWMS-UHFFFAOYSA-N 0.000 description 9
- 239000000463 material Substances 0.000 description 8
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 7
- 239000010936 titanium Substances 0.000 description 6
- NJLLQSBAHIKGKF-UHFFFAOYSA-N dipotassium dioxido(oxo)titanium Chemical compound [K+].[K+].[O-][Ti]([O-])=O NJLLQSBAHIKGKF-UHFFFAOYSA-N 0.000 description 5
- 230000004907 flux Effects 0.000 description 5
- 229910044991 metal oxide Inorganic materials 0.000 description 5
- 150000004706 metal oxides Chemical class 0.000 description 5
- 229910052700 potassium Inorganic materials 0.000 description 5
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 4
- 239000000835 fiber Substances 0.000 description 4
- 238000009413 insulation Methods 0.000 description 4
- 239000011591 potassium Substances 0.000 description 4
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 4
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 3
- 239000010425 asbestos Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 229910052895 riebeckite Inorganic materials 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 229910052788 barium Inorganic materials 0.000 description 2
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 2
- AYJRCSIUFZENHW-UHFFFAOYSA-L barium carbonate Chemical compound [Ba+2].[O-]C([O-])=O AYJRCSIUFZENHW-UHFFFAOYSA-L 0.000 description 2
- 229910052792 caesium Inorganic materials 0.000 description 2
- -1 deuterium carbonates Chemical class 0.000 description 2
- 239000011810 insulating material Substances 0.000 description 2
- 239000012774 insulation material Substances 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 229910052701 rubidium Inorganic materials 0.000 description 2
- 239000007858 starting material Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910018626 Al(OH) Inorganic materials 0.000 description 1
- 229910019440 Mg(OH) Inorganic materials 0.000 description 1
- 235000008331 Pinus X rigitaeda Nutrition 0.000 description 1
- 235000011613 Pinus brutia Nutrition 0.000 description 1
- 241000018646 Pinus brutia Species 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- WDIHJSXYQDMJHN-UHFFFAOYSA-L barium chloride Chemical compound [Cl-].[Cl-].[Ba+2] WDIHJSXYQDMJHN-UHFFFAOYSA-L 0.000 description 1
- 229910001626 barium chloride Inorganic materials 0.000 description 1
- 150000001553 barium compounds Chemical class 0.000 description 1
- 229910001632 barium fluoride Inorganic materials 0.000 description 1
- AYJRCSIUFZENHW-DEQYMQKBSA-L barium(2+);oxomethanediolate Chemical compound [Ba+2].[O-][14C]([O-])=O AYJRCSIUFZENHW-DEQYMQKBSA-L 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 229910052805 deuterium Inorganic materials 0.000 description 1
- 238000004079 fireproofing Methods 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229910000476 molybdenum oxide Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- PQQKPALAQIIWST-UHFFFAOYSA-N oxomolybdenum Chemical compound [Mo]=O PQQKPALAQIIWST-UHFFFAOYSA-N 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000000634 powder X-ray diffraction Methods 0.000 description 1
- 239000012254 powdered material Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000002982 water resistant material Substances 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Landscapes
- Inorganic Compounds Of Heavy Metals (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
- Compounds Of Iron (AREA)
Description
産業上の利用分野
本発明はホーランダイト型構造の繊維状バリウ
ムチタン酸塩の製造法に関する。更に詳しくは、
高温断熱性を有し、高温断熱材料、耐水材料等と
して優れた一次元の極めて大きなトンネル構造を
持つたホーランダイト型構造の繊維状バリウムチ
タン酸塩の製造法に関する。
従来技術
従来、広く利用されてきた高温断熱材としては
アスベストがある。しかし、アスベストは公害を
起こす欠点があり、その代替材料の開発が要望さ
れている。アスベストの代替材料として、さきに
本発明者の一人が新しいチタン酸カリウム繊維を
開発した(特公昭55−25157号公報参照)。しか
し、このチタン酸カリウム繊維は、断熱性ではセ
ラミツクスの中で抜群に優れているが、融点が
1370℃であるため、実際使用可能な温度は1200℃
程度までである問題点があつた。
発明の目的
本発明の目的は前記チタン酸カリウム繊維より
もより高温において使用可能な高温断熱材の製造
法を提供するにある。
発明の構成
本発明者らはチタン酸カリウムについて、永年
に亘る研究の結果、その断熱特性の原因が一次元
的なトンネル構造に関係することを明らかにし
た。その結果、チタン酸カリウムよりも更に大き
いトンネル構造を持ち、かつ融点の高い物質を得
んと鋭意研究を重ね、ホーランダイト型構造を有
するバリウムチタン酸塩の単結晶を合成したとこ
ろ、熱伝導率の極めて小さい、かつ高温に耐える
断熱特性を示すことを知見した。
また、ホーランダイト型構造のバリウムチタン
酸塩の単結晶は、一般式 Bax(ByTiz)8O16
(ただし、BはMg、二価遷移金属、Al、Fe、Cr
およびGaから選ばれた金属、xは0.5〜3、yは
0.5〜3、zは5〜8を表わす)で示されるホー
ランダイト型構造を有するバリウムチタン酸塩も
しくはその製造原料から特定のフラツクスを使用
し、結晶育成することにより得られることが分つ
た。これらの知見に基いて本発明を完成した。
本発明の要旨は、前記ホーランダイト型構造を
有するバリウムチタン酸塩もしくはその製造原料
に、一般式 A2MoO4・nMoO3(ただし、Aは
K、RbまたはCs、n=0〜3を表わす)で示さ
れるモリブデン酸金属塩、もしくはその製造原料
を混合し、該混合物を溶融してその溶融体から結
晶育成する方法にある。
本発明におけるホーランダイト型構造を有する
一般式で示されるB成分であるMg、Cu、Zn、
Ni、Coの二価遷移金属、Al、Fe、Cr、Gaはい
ずれもトンネルの枠組を作るTiO6の八面体中の
Tiの席を置換して占有することができる金属で
ある。特にMgとAlはTiを置換し易く、試料が作
り易く、かつ融点が高くなる点で好ましい。また
B成分は前記に示した2元素以上の固溶成分であ
つてもよい。また、一般式で示されるx、yはい
ずれも0.5〜3の範囲であることが必要であり、
好ましくは1.0〜2.4の範囲である。この範囲外で
は目的のホーランダイト型構造を有するバリウム
チタン酸塩以外の相が生成して混合相となり、熱
伝導率を大きくしたり、機械的強度の低下をきた
す。
また、zは5〜8であることが必要である。こ
の範囲外ではトンネル構造のTiO6の八面体が得
難い。
本発明において用いるホーランダイト型構造を
有するバリウムチタン酸塩は次の方法によつて製
造される。酸化バリウム(BaO)、一般式B〓O
(ただし、B〓はMgまたは二価遷移金属を表わす)
で示される金属酸化物または一般式B〓2O3(ただ
し、B〓はAl、Fe、CrまたはGaを表わす)で示
される金属酸化物、および酸化チタン(TiO2)
を、モル比で、
BaO:B〓O:TiO2
=2:1:3〜5:2:3
または、
BaO:B〓O:TiO2=2:1:3〜4:3:3
の割合の混合物または固溶体からなるものを製造
原料とする。
前記原料のBaOに代え、加熱によりBaOを生
成するバリウム化合物、例えばBa(OH)2、
BaCO3、Ba(NO3)2、BaF2、BaCl2、BaB4O7、
BaSO4なども使用し得られる。
また、B成分の金属酸化物に代え、加熱により
該金属酸化物を生成する化合物、例えばMgCO3、
二価遷移金属の炭酸化物、Mg(OH)2、二価遷移
金属の水酸化物、MgH2(CO3)2、二価遷移金属
の重水素炭酸化物、Al(OH)3、Fe(OH)3、Cr
(OH)3、Ga(OH)3、Al2(CO3)3、Fe2(CO3)3、
Cr2(CO3)3、Ga2(CO3)3なども使用し得られる。
前記TiO2も同様に加熱によりTiO2を生成する
化合物も使用し得られる。これらの金属酸化物以
外の金属化合物を使用する場合は、前記配合モル
割合は金属酸化物に換算してその割合を決定す
る。
前記のホーランダイト型構造を有するバリウム
チタン酸塩もしくはその製造原料に、一般式
A2MoO4・nMoO3(ただし、Aおよびnは前記と
同じ金属および数を表わす)で示されるモリブデ
ン酸金属塩を混合する。これらのモリブデン酸金
属塩はフラツクスとして作用し、MoO3は溶解度
を上げる作用をする。そして低揮発性であつて、
揮発による公害の心配もなく、また水に易溶性の
ため、生成した繊維の分離が簡単で回収が容易で
ある特性を有する。
両者の混合割合は、モル%で10:90〜50:50の
割合であることが好ましい。
この混合割合により多少生成の様子が異なる。
溶融体の塩基性度の相違により、低塩基性側では
ルチル相との混合物となつたり、また高塩基性で
余りにも塩基性が高くなると結晶し難かつたりす
ることがある。このような場合は調節剤として
K2O成分とMoO3成分を用いてその量比を制御す
ればよい。
これらの混合物を例えば800℃〜1500℃で溶融
して溶融体を作り、その溶融体から結晶育成する
と、ホーランダイト型構造を有するバリウムチタ
ン酸塩の繊維状単結晶が得られる。
溶融体からの結晶育成法としては、(1)溶融体の
温度から約700℃の温度まで徐冷する徐冷法。(2)
一定温度に保持してフラツクス成分を蒸発させる
蒸発法。(3)ルツボの上下間に温度差を与える温度
差法。(4)ルツボの底に空気を吹きつけるか、また
は冷却物を接触させて局部的に冷却する局部冷却
法、および(5)前記方法の組合せによる方法によつ
て行うことができる。
本発明の方法で得られるバリウムチタン酸塩
は、TiO6八面体でトンネル構造を作りそのトン
ネルの中をBaが占有した構造で、トンネルのC
軸方向へ伸びた一次元構造のものである。
また、バリウムとアルカリ金属、特にカリウ
ム、二価遷移金属のCuのイオンが固溶したホー
ランダイト型構造を有するバリウムチタン酸塩の
繊維状結晶も得られる。
実施例 1
炭酸バリウム、酸化アルミニウムおよび酸化チ
タンの各粉末を、モル比でBaCO3:Al2O3:
TiO2=4:4:6の割合で混合した。
また、モリブデン酸カリウムと酸化モリブデン
の各粉末を、モル比でK2MoO4:MoO3=1:0.5
の割合で混合した。
この両混合物をモル%で、(BaCO3)4・
(Al2O3)2・(TiO2)6:(K2MoO4)・(MoO3)0.5=
20:8の割合で混合し、出発原料とした。この出
発原料約30gを30mlの白金るつぼに充填し、
5kWの炭化珪素電気炉で1300℃で約10時間加熱
した。得られた溶融体を950℃附近まで8℃/h
の速度で冷却した。冷却後るつぼを電気炉から取
出し、室温まで放冷した。結晶は温水中でフラツ
クスを溶解して分離した。得られた結晶はC軸方
向の伸長した繊維状で灰色を呈していた。X線粉
末回折の結果、ホーランダイト型構造のバリウム
チタン酸塩で、その化学組成は(Ba、K)0.8
(Al1.6Ti6.4)8O16で、カリウムが微量であるが、
バリウムと固溶していた。
結晶は最大0.2×5mm、平均0.01×1mmであり、
融点は約1500℃であつた。
実施例 2〜7
ホーランダイト型構造のバリウムチタン酸塩の
組成を変え、また徐冷速度を8℃/hとし、ほか
実施例1と同様にして結晶育成した結果は次の通
りであつた。
FIELD OF INDUSTRIAL APPLICATION The present invention relates to a method for producing fibrous barium titanate having a hollandite structure. For more details,
This invention relates to a method for producing fibrous barium titanate having a hollandite-type structure and having a one-dimensional extremely large tunnel structure that has high-temperature insulation properties and is excellent as a high-temperature insulation material, a water-resistant material, etc. Prior Art Asbestos is a high-temperature insulation material that has been widely used in the past. However, asbestos has the disadvantage of causing pollution, and there is a demand for the development of alternative materials. One of the inventors of the present invention previously developed a new potassium titanate fiber as an alternative material to asbestos (see Japanese Patent Publication No. 55-25157). However, although this potassium titanate fiber has outstanding insulation properties among ceramics, it has a low melting point.
Since it is 1370℃, the actual usable temperature is 1200℃.
There were some problems to a certain extent. OBJECTS OF THE INVENTION An object of the present invention is to provide a method for producing a high-temperature heat insulating material that can be used at higher temperatures than the potassium titanate fibers. Structure of the Invention As a result of many years of research into potassium titanate, the present inventors have revealed that the cause of its heat insulating properties is related to its one-dimensional tunnel structure. As a result, they conducted intensive research to obtain a substance with a larger tunnel structure than potassium titanate and a higher melting point, and when they synthesized a single crystal of barium titanate with a hollandite structure, they found that the thermal conductivity was It was discovered that the material has an extremely small amount of heat and exhibits heat insulating properties that can withstand high temperatures. In addition, a single crystal of barium titanate with a hollandite structure has the general formula B x (B y Ti z ) 8 O 16 (where B is Mg, a divalent transition metal, Al, Fe, Cr
and Ga, x is 0.5 to 3, y is
It has been found that it can be obtained by crystal growth using a specific flux from a barium titanate having a hollandite structure (0.5 to 3, z representing 5 to 8) or a raw material for its production. The present invention was completed based on these findings. The gist of the present invention is that the above-mentioned barium titanate having a hollandite structure or a raw material for its production has a general formula A 2 MoO 4 .nMoO 3 (where A represents K, Rb or Cs, n = 0 to 3). ) or its production raw materials are mixed, the mixture is melted, and crystals are grown from the melt. Mg, Cu, Zn, which is the B component represented by the general formula having a hollandite structure in the present invention,
Ni, Co, divalent transition metals, Al, Fe, Cr, and Ga are all present in the TiO 6 octahedron that forms the tunnel framework.
It is a metal that can replace and occupy the seat of Ti. In particular, Mg and Al are preferable because they can easily replace Ti, facilitate sample preparation, and have a high melting point. Moreover, the B component may be a solid solution component of two or more of the above-mentioned elements. In addition, both x and y shown in the general formula must be in the range of 0.5 to 3,
Preferably it is in the range of 1.0 to 2.4. Outside this range, a phase other than the barium titanate having the desired hollandite structure is formed, resulting in a mixed phase, which increases thermal conductivity and reduces mechanical strength. Moreover, z needs to be 5-8. Outside this range, it is difficult to obtain a TiO 6 octahedron with a tunnel structure. The barium titanate having a hollandite structure used in the present invention is produced by the following method. Barium oxide (BaO), general formula B〓O
(However, B〓 represents Mg or divalent transition metal)
Metal oxides represented by or represented by the general formula B〓 2 O 3 (where B〓 represents Al, Fe, Cr or Ga), and titanium oxide (TiO 2 )
In terms of molar ratio, BaO:B〓O: TiO2 = 2:1:3 to 5:2:3 or BaO:B〓O: TiO2 = 2:1:3 to 4:3:3. The raw material for production is a mixture or solid solution of In place of the raw material BaO, a barium compound that generates BaO upon heating, such as Ba(OH) 2 ,
BaCO3 , Ba( NO3 ) 2 , BaF2 , BaCl2 , BaB4O7 ,
BaSO 4 etc. can also be used. In addition, instead of the metal oxide of component B, a compound that generates the metal oxide upon heating, such as MgCO 3 ,
Carbonates of divalent transition metals, Mg(OH) 2 , hydroxides of divalent transition metals, MgH 2 (CO 3 ) 2 , deuterium carbonates of divalent transition metals, Al(OH) 3 , Fe(OH) ) 3 , Cr
(OH) 3 , Ga(OH) 3 , Al 2 (CO 3 ) 3 , Fe 2 (CO 3 ) 3 ,
Cr 2 (CO 3 ) 3 , Ga 2 (CO 3 ) 3 and the like can also be used. Similarly, a compound that generates TiO 2 upon heating can be used as the TiO 2 mentioned above. When a metal compound other than these metal oxides is used, the molar ratio is determined in terms of the metal oxide. The general formula
A molybdate metal salt represented by A 2 MoO 4 .nMoO 3 (A and n represent the same metals and numbers as above) is mixed. These molybdate metal salts act as a flux, and MoO 3 acts to increase solubility. And it has low volatility,
There is no concern about pollution due to volatilization, and since it is easily soluble in water, the produced fibers can be easily separated and recovered. The mixing ratio of both is preferably 10:90 to 50:50 in mol%. The appearance of production differs somewhat depending on the mixing ratio.
Due to the difference in basicity of the melt, if the basicity is low, the melt may become a mixture with the rutile phase, or if the basicity is too high, it may be difficult to crystallize. In such cases, as a regulator
The quantity ratio may be controlled using the K 2 O component and the MoO 3 component. When these mixtures are melted at, for example, 800° C. to 1500° C. to form a melt, and crystals are grown from the melt, a fibrous single crystal of barium titanate having a hollandite structure is obtained. Methods for growing crystals from a melt include (1) a slow cooling method in which the temperature of the melt is slowly cooled to approximately 700°C; (2)
An evaporation method that evaporates flux components while maintaining a constant temperature. (3) Temperature difference method that creates a temperature difference between the top and bottom of the crucible. (4) A local cooling method in which air is blown onto the bottom of the crucible or a cooling substance is brought into contact with the crucible to locally cool it, and (5) a combination of the above methods can be used. The barium titanate obtained by the method of the present invention has a tunnel structure made of TiO 6 octahedrons and has a structure in which Ba occupies the tunnel.
It has a one-dimensional structure extending in the axial direction. In addition, fibrous crystals of barium titanate having a hollandite structure in which barium and alkali metals, particularly potassium, and Cu ions, which are divalent transition metals, are solidly dissolved can also be obtained. Example 1 Barium carbonate, aluminum oxide, and titanium oxide powders were prepared in a molar ratio of BaCO 3 :Al 2 O 3 :
TiO 2 was mixed at a ratio of 4:4:6. In addition, each powder of potassium molybdate and molybdenum oxide was mixed in a molar ratio of K 2 MoO 4 :MoO 3 =1:0.5.
mixed in the ratio of Both mixtures are expressed in mol% as (BaCO 3 ) 4 .
(Al 2 O 3 ) 2・(TiO 2 ) 6 : (K 2 MoO 4 )・(MoO 3 ) 0.5 =
The mixture was mixed at a ratio of 20:8 and used as a starting material. Approximately 30g of this starting material was filled into a 30ml platinum crucible,
It was heated at 1300°C for about 10 hours in a 5kW silicon carbide electric furnace. The obtained melt is heated at 8℃/h until it reaches around 950℃.
It was cooled at a rate of . After cooling, the crucible was taken out of the electric furnace and allowed to cool to room temperature. The crystals were separated by dissolving the flux in hot water. The obtained crystals were fibrous and gray in color, extending in the C-axis direction. As a result of X-ray powder diffraction, it is barium titanate with a hollandite structure, and its chemical composition is (Ba, K) 0.8
(Al 1.6 Ti 6.4 ) 8 O 16 , with a trace amount of potassium,
It was in solid solution with barium. The maximum crystal size is 0.2 x 5 mm, and the average size is 0.01 x 1 mm.
The melting point was approximately 1500°C. Examples 2 to 7 Crystals were grown in the same manner as in Example 1 except that the composition of barium titanate having a hollandite structure was changed and the slow cooling rate was 8° C./h. The results were as follows.
【表】
なお実施例1におけるAl2O3に代え、Fe、Cr、
およびGaの酸化物を使用した場合もほぼ同じ結
果が得られた。また、フラツクスのKに代え、
Rb、Csを使用した場合もほぼ同様な結果が得ら
れた。
実施例 8
実施例1と同様にしてBa1.4Al2.8Ti5.2O16の結晶
を作つた。比較のためK2.0Al2.0Ti6O16の焼結体を
作り、それぞれの試料の室温および1000Kにおけ
る比熱容量Cp、熱拡散率α、および熱伝導率K
を測定した結果は次の通りであつた。K=ρ・
Cp・α(ρは密度を表わす)[Table] Note that instead of Al 2 O 3 in Example 1, Fe, Cr,
Almost the same results were obtained when Ga oxide was used. Also, instead of K for flux,
Almost similar results were obtained when Rb and Cs were used. Example 8 A Ba 1.4 Al 2.8 Ti 5.2 O 16 crystal was produced in the same manner as in Example 1. For comparison, a sintered body of K 2.0 Al 2.0 Ti 6 O 16 was prepared, and the specific heat capacity Cp, thermal diffusivity α, and thermal conductivity K of each sample at room temperature and 1000K were determined.
The results of the measurements were as follows. K=ρ・
Cp・α (ρ represents density)
【表】
上記表から、本発明のバリウムチタン酸塩は六
チタン酸カリウム焼結体より20%以上低い値を示
している。また、室温よりも1000Kの方が低い熱
伝導率を示し、高温下で断熱性に優れた特性を有
することを示している。
発明の効果
本発明の方法によると、融点が1500℃以上で高
温に堪え、かつ、高断熱性の優れた特性を有する
ホーランダイト型構造の繊維状バリウムチタン酸
塩が得られ、これをマツト材、シート材、電線お
よび鉄骨被覆材、各種保温材、耐火材として有効
に利用し得られる。また粉末状のものは耐熱性断
熱塗料の素材ともなる優れた効果を奏し得られ
る。[Table] From the above table, the barium titanate of the present invention shows a value that is 20% or more lower than that of the potassium hexatitanate sintered body. Furthermore, it exhibits lower thermal conductivity at 1000K than at room temperature, indicating that it has excellent heat insulation properties at high temperatures. Effects of the Invention According to the method of the present invention, a fibrous barium titanate having a hollandite structure, which has a melting point of 1500°C or higher, can withstand high temperatures, and has excellent properties of high heat insulation, is obtained, and this is used as a material for making pine wood. It can be effectively used as sheet materials, electric wire and steel frame covering materials, various heat insulating materials, and fireproofing materials. Powdered materials can also be used as materials for heat-resistant heat-insulating paints.
Claims (1)
およびGaから選ばれた金属、xは0.5〜3、yは
0.5〜3、zは5〜8を表わす。)で示されるホー
ランダイト型構造を有するバリウムチタン酸塩も
しくはその製造原料化合物の混合物に、一般式 A2MoO4・nMoO3 (ただし、AはK、RbまたはCs、nは0〜3を
表わす)で示されるモリブデン酸金属塩もしくは
その製造原料を混合し、該混合物を溶融してその
溶融体から結晶育成することを特徴とするホーラ
ンダイト型構造の繊維状バリウムチタン酸塩の製
造法。 2 一般式Bax(ByTiz)8O16で示されるホーラン
ダイト型構造を有するバリウムチタン酸塩の製造
原料化合物の混合物が、BaO、一般式B〓O(ただ
し、B〓はMgまたは二価遷移金属を表わす)で示
される金属酸化物または一般式B〓2O3(ただし、
B〓はAl、Fe、CrまたはGaを表わす)で示され
る金属酸化物、およびTiO2をモル比で、 BaO:B〓O:TiO2=2:1:3〜5:2:3 または BaO:B〓2O3:TiO2 =2:1:3〜4:3:3 の割合の混合物もしくはその固溶体である特許請
求の範囲第1項記載のホーランダイト型構造の繊
維状バリウムチタン酸塩の製造法。 3 溶融体からの結晶育成法が、徐冷法、蒸発
法、温度差法、局部冷却法またはそれらの組合せ
法である特許請求の範囲第1項記載の製造法。[Claims] 1 General formula Ba x (B y Ti z ) 8 O 16 (B is Mg, divalent transition metal, Al, Fe, Cr
and Ga, x is 0.5 to 3, y is
0.5-3, z represents 5-8. ), or a mixture of barium titanate having a hollandite -type structure or a compound as a raw material for its production, is added to a mixture of barium titanate having a hollandite-type structure or a raw material compound for its production. 1. A method for producing a fibrous barium titanate having a hollandite structure, which comprises mixing molybdate metal salts represented by () or raw materials for producing the same, melting the mixture, and growing crystals from the melt. 2 A mixture of raw material compounds for producing barium titanate having a hollandite structure represented by the general formula B x (B y Ti z ) 8 O 16 is BaO, the general formula B〓O (where B〓 is Mg or represents a divalent transition metal) or has the general formula B〓 2 O 3 (however,
B〓 represents Al, Fe, Cr or Ga) and TiO 2 in molar ratio, BaO:B〓O:TiO 2 = 2:1:3 to 5:2:3 or BaO The fibrous barium titanate having a hollandite structure according to claim 1, which is a mixture or a solid solution thereof in a ratio of :B〓 2 O 3 :TiO 2 = 2:1:3 to 4:3:3. manufacturing method. 3. The manufacturing method according to claim 1, wherein the method for growing crystals from a melt is a slow cooling method, an evaporation method, a temperature difference method, a local cooling method, or a combination thereof.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11645983A JPS6011227A (en) | 1983-06-28 | 1983-06-28 | Manufacture of fibrous barium titanate having hollandite type structure |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11645983A JPS6011227A (en) | 1983-06-28 | 1983-06-28 | Manufacture of fibrous barium titanate having hollandite type structure |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS6011227A JPS6011227A (en) | 1985-01-21 |
JPH0346432B2 true JPH0346432B2 (en) | 1991-07-16 |
Family
ID=14687636
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP11645983A Granted JPS6011227A (en) | 1983-06-28 | 1983-06-28 | Manufacture of fibrous barium titanate having hollandite type structure |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6011227A (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0316680B1 (en) * | 1987-11-19 | 1992-07-22 | Degussa Aktiengesellschaft | Use of compounds of metal oxides or of metal oxides and non-metal oxides as inorganic pigments |
JPH0736706Y2 (en) * | 1991-09-26 | 1995-08-23 | 株式会社山田プランニング | Goldfish scooping toys |
JPH05285277A (en) * | 1992-04-13 | 1993-11-02 | Sankyo Seiki Mfg Co Ltd | Action mechanism of doll and the like and method for setting initial position of motion |
FR2833257B1 (en) * | 2001-12-11 | 2004-01-30 | Commissariat Energie Atomique | HOLLANDITE STRUCTURE CERAMIC INCORPORATING CESIUM FOR USE IN POSSIBLE CONDITIONING OF RADIOACTIVE CESIUM AND PROCESSES FOR SYNTHESIS |
-
1983
- 1983-06-28 JP JP11645983A patent/JPS6011227A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPS6011227A (en) | 1985-01-21 |
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