RO119458B1 - Carbothermal process for preparing barium titanate - Google Patents
Carbothermal process for preparing barium titanate Download PDFInfo
- Publication number
- RO119458B1 RO119458B1 ROA200100524A RO200100524A RO119458B1 RO 119458 B1 RO119458 B1 RO 119458B1 RO A200100524 A ROA200100524 A RO A200100524A RO 200100524 A RO200100524 A RO 200100524A RO 119458 B1 RO119458 B1 RO 119458B1
- Authority
- RO
- Romania
- Prior art keywords
- barium titanate
- graphite
- barium
- titanium
- temperature
- Prior art date
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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 title claims abstract description 10
- 229910002113 barium titanate Inorganic materials 0.000 title claims abstract description 10
- 238000004519 manufacturing process Methods 0.000 title abstract description 3
- AYJRCSIUFZENHW-UHFFFAOYSA-L barium carbonate Chemical compound [Ba+2].[O-]C([O-])=O AYJRCSIUFZENHW-UHFFFAOYSA-L 0.000 claims abstract description 14
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 12
- 239000010439 graphite Substances 0.000 claims abstract description 12
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims abstract description 10
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 8
- 239000000203 mixture Substances 0.000 claims abstract description 6
- 235000019441 ethanol Nutrition 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 9
- 239000010936 titanium Substances 0.000 claims description 8
- 229910052719 titanium Inorganic materials 0.000 claims description 5
- 238000000265 homogenisation Methods 0.000 abstract 1
- 238000006243 chemical reaction Methods 0.000 description 10
- 238000002485 combustion reaction Methods 0.000 description 5
- 239000000843 powder Substances 0.000 description 5
- 239000000919 ceramic Substances 0.000 description 4
- 229910010413 TiO 2 Inorganic materials 0.000 description 3
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 3
- 239000000376 reactant Substances 0.000 description 3
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- XBYNNYGGLWJASC-UHFFFAOYSA-N barium titanium Chemical compound [Ti].[Ba] XBYNNYGGLWJASC-UHFFFAOYSA-N 0.000 description 2
- 238000005469 granulation Methods 0.000 description 2
- 230000003179 granulation Effects 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000011541 reaction mixture Substances 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- ZJRXSAYFZMGQFP-UHFFFAOYSA-N barium peroxide Chemical compound [Ba+2].[O-][O-] ZJRXSAYFZMGQFP-UHFFFAOYSA-N 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
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 239000003985 ceramic capacitor Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910001510 metal chloride Inorganic materials 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000010517 secondary reaction Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
Landscapes
- Compositions Of Oxide Ceramics (AREA)
Abstract
Description
Invenția se referă la un procedeu carbotermic, de obținere a titanatului de bariu, sub formă de pulbere, utilizat la confecționarea condensatoarelor ceramice, de permitivitate înaltă.The invention relates to a carbothermal process for obtaining barium titanate, in powder form, used in the manufacture of ceramic capacitors, of high permittivity.
Este cunoscută metoda de sinteză a titanatului de bariu, hexagonal, prin metoda reacției autopropagate, la temperatură înaltă.The synthesis method of hexagonal barium titanate is known by the high temperature self-propelled reaction method.
Se cunoaște, de asemenea, prepararea titanatului de bariu, prin reacție de autopropagare, la temperatură înaltă, folosind ca sursă de bariu, peroxidul de bariu, BaO2, iar ca sursă de titan, bioxidul de titan TiO2, titan metalic, Ti și TiCI3. Reacția a fost inițiată în aer, cu ajutorul unui filament încălzit. Din BaO2 și Ti s-a obținut BaTiO3 hexagonal, în timp ce BaTiO3 tetragonal s-a obținut din amestecurile reactante, compuse din BaO2, Ti, TiO2; BaO2, TiCI3 și BaO2, TiO2, TiCI3.Also known is the preparation of barium titanate, by self-propagating reaction, at high temperature, using as barium source, barium peroxide, BaO 2 , and as source of titanium, titanium dioxide TiO 2 , titanium metal, Ti and TiCI 3 . The reaction was initiated in the air with the help of a heated filament. BaO 2 and Ti of BaTiO 3 was obtained hexagonal, while the tetragonal BaTiO 3 was obtained from the reaction mixtures consisting of BaO 2, Ti, TiO 2; BaO 2 , TiCI 3 and BaO 2 , TiO 2 , TiCI 3 .
Dezavantajul metodelor care folosesc TiCI3 ca sursă de combustie cu BaO2 constă în formarea, ca produs secundar a BaCI2, care trebuie eliminată. în plus, implicarea clorurilor metalice în reacțiile autopropagate este mai puțin obișnuită și, prin urmare, cunoștințele despre mecanismele acestor reacții sunt limitate.The disadvantage of the methods that use TiCI 3 as a combustion source with BaO 2 is the formation, as a by-product of BaCI 2 , which must be eliminated. In addition, the involvement of metal chlorides in self-propagating reactions is less common and, therefore, knowledge about the mechanisms of these reactions is limited.
Problema tehnică, pe care o rezolvă invenția, este elaborarea unui procedeu de obținere a titanatului de bariu, utilizat în compoziții ceramice cu bune caracteristici dielectrice.The technical problem, which the invention solves, is the elaboration of a process for obtaining barium titanium, used in ceramic compositions with good dielectric characteristics.
Procedeul conform invenției înlătură dezavantajele menționate prin aceea că se realizează un amestec de carbonat de bariu și titan pulbere în raport molar de 1:1, se adaugă un exces de 0,5% grafit fin măcinat, se omogenizează pe cale umedă în alcool etilic p.a., se calcinează, timp de 3 h, în aer, la o temperatură de 1300°C.The process according to the invention removes the mentioned disadvantages by making a mixture of barium carbonate and titanium powder in a molar ratio of 1: 1, an excess of 0.5% finely ground graphite is added, it is homogenized in aqueous ethyl alcohol. , it is calcined for 3 hours in air at a temperature of 1300 ° C.
Prin aplicarea invenției, se obțin următoarele avantaje:By applying the invention, the following advantages are obtained:
- se reduce temperatura de obținere a titanatului de bariu de la 1350...1400°C, la 1300°C;- the barium titanate temperature is reduced from 1350 ... 1400 ° C, to 1300 ° C;
- se obține o pulbere cu granulație uniformă;- a powder with uniform granulation is obtained;
- nu există compuși secundari de reacție;- there are no secondary reaction compounds;
- produsul obținut are o puritate înaltă;- the product obtained has a high purity;
- procedeul este ieftin și ușor de aplicat;- the process is cheap and easy to apply;
- ceramica preparată din pulberea de titanat de bariu, obținută prin acest procedeu, are o constantă dielectrică egală cu 1400 la temperatura camerei și cu 8300 la temperatura punctului Curie (127°C), la 1 kHz.- the ceramic prepared from the barium titanium powder, obtained by this process, has a dielectric constant equal to 1400 at room temperature and 8300 at Curie point temperature (127 ° C), at 1 kHz.
Procedeul este considerat carbotermic, deoarece se utilizează grafitul ca sursă de combustie. S-a utilizat combustia grafitului cu oxigen și încălzirea electrică pentru inițierea arderii grafitului (la 690°C) și pentru compensarea pierderilor de căldură din cuptor, în timpul reacției dintre carbonatul de bariu și titan.The process is considered carbothermal, because graphite is used as a combustion source. Oxygen graphite combustion and electric heating were used to initiate the combustion of graphite (at 690 ° C) and to compensate for heat losses in the furnace, during the reaction between barium carbonate and titanium.
Se prezintă, în continuare, un exemplu de realizare a invenției.The following is an example of an embodiment of the invention.
Se prepară un amestec din părți molare, egale, de carbonat de bariu, titan pulbere și un exces de 0,5% grafit fin măcinat.A mixture of molar parts, equal, barium carbonate, titanium powder and an excess of 0.5% finely ground graphite is prepared.
Grafitul se aprinde la 690°C, iar reacția sa de ardere are un efect exoterm egal cu 94 kcal pentru un mol de C. Reacția dintre carbonatul de bariu și titan este puternic endotermă, entalpia de reacție fiind egală cu 104,5 kcal la 300K și 1 atm. Se folosește grafit spectral pur cu o granulație micronică (diametrul mediu al particulelor ~ 10 pm), pulbere de titan cu diametrul particulei <100 pm și carbonat de bariu de puritate >99%. Amestecarea reactanților se realizează în alcool etilic. Raportul grafit:amestec reactant se stabilește pe baza entalpiilor reacțiilor de mai sus. Practic, se utilizează un raport mai mare, excesul de grafit compensând pierderile de căldură și asigurând o viteză de reacție suficient de mare.Graphite ignites at 690 ° C, and its combustion reaction has an exothermic effect equal to 94 kcal for one mole of C. The reaction between barium carbonate and titanium is strongly endothermic, the reaction enthalpy being 104.5 kcal at 300K. and 1 atm. Pure spectral graphite with a micron granulation (mean particle diameter ~ 10 pm), titanium powder with particle diameter <100 pm and barium carbonate of purity> 99% are used. The mixing of the reactants is carried out in ethyl alcohol. Graphite ratio: reactant mixture is determined based on the enthalpies of the above reactions. Basically, a higher ratio is used, the excess graphite compensating for heat losses and ensuring a sufficiently high reaction rate.
Se obține titanat de bariu tetragonal, după 3 h de tratament termic, la 1300°C a amestecului reactant. Sub această temperatură, reactanții nu intră complet în reacție, când durata calcinării este de 4...8 h. Pulberea de titanat de bariu, obținută, se caracterizează prin difracție de raze X evidențiindu-se numai prezența formei tetragonale a titanatului de bariu.Tetragonal barium titanate is obtained, after 3 hours of heat treatment, at 1300 ° C of the reaction mixture. Below this temperature, the reactants do not completely react, when the duration of the calcination is 4 ... 8 h. The obtained barium titanate powder is characterized by X-ray diffraction, highlighting only the presence of the tetragonal form of the barium titanate.
RO 119458 Β1RO 119458 Β1
Ceramica dielectrică preparată din această pulbere prin presare la 650 Kgf/cm2 și sinterizare la 1300°C, 0,5 h în aer, prezintă o constanta dielectrică egală cu 1400, la temperatura camerei și 8300 la temperatura punctului Curie (127°C). Măsurătorile electrice se efectuează la 1 kHz.The dielectric ceramic prepared from this powder by pressing at 650 Kgf / cm 2 and sintering at 1300 ° C, 0.5 h in air, has a dielectric constant equal to 1400, at room temperature and 8300 at Curie point temperature (127 ° C). . Electrical measurements are performed at 1 kHz.
Ceramica obținută are caracteristicile dielectrice, corespunzătoare pentru condensatoare de permitivitate înaltă.The ceramic obtained has the dielectric characteristics, suitable for high permittivity capacitors.
Claims (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ROA200100524A RO119458B1 (en) | 2001-05-14 | 2001-05-14 | Carbothermal process for preparing barium titanate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ROA200100524A RO119458B1 (en) | 2001-05-14 | 2001-05-14 | Carbothermal process for preparing barium titanate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| RO119458B1 true RO119458B1 (en) | 2004-11-30 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| ROA200100524A RO119458B1 (en) | 2001-05-14 | 2001-05-14 | Carbothermal process for preparing barium titanate |
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| RO (1) | RO119458B1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7897135B2 (en) * | 2004-09-27 | 2011-03-01 | University Of Houston | Carbon combustion synthesis of oxides |
-
2001
- 2001-05-14 RO ROA200100524A patent/RO119458B1/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7897135B2 (en) * | 2004-09-27 | 2011-03-01 | University Of Houston | Carbon combustion synthesis of oxides |
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