IPC분류정보
| 국가/구분 |
United States(US) Patent
등록
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| 국제특허분류(IPC7판) |
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| 출원번호 |
US-0494737
(1974-08-05)
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발명자
/ 주소 |
- Harrington Roy V. (Brecksville OH) Beal Donald F. (Medina OH)
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| 출원인 / 주소 |
- Ferro Corporation (Cleveland OH 02)
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| 인용정보 |
피인용 횟수 :
28 인용 특허 :
0 |
초록
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A cordierite-type glass-ceramic and a process for its preparation are disclosed, characterized in that a nucleating agent in a small amount is added preferably to a glass batch capable of producing cordierite. The nucleating agent aids in forming a glass-ceramic refractory of relatively large amount
A cordierite-type glass-ceramic and a process for its preparation are disclosed, characterized in that a nucleating agent in a small amount is added preferably to a glass batch capable of producing cordierite. The nucleating agent aids in forming a glass-ceramic refractory of relatively large amounts of crystalline cordierite. The melt is quenched and ground to an average particle size no greater than about minus 325 U.S. Standard sieve. This particle size in combination with a relatively small amount of a nucleating agent has been found to increase the amount of cordierite formed during crystallization and simultaneously decrease the amount of glassy phase remaining in the glass-ceramic. In this manner, the ultimate product more nearly resembles pure cordierite. The nucleating agent includes the compounds, usually the oxides, of Mo, Ta, Zr, Nb, Ti, Li, As, and mixtures thereof. The preferred nucleating additive or agent is Nb2O5. The present refractories may have a coefficient of thermal expansion less than 1.60 ×106 inch/inch/°C from room temperature to about 600°C as determined by the Orton dilatometer.
대표청구항
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In a process for producing a cordierite glassceramic by fusing a mixture of ingredients to form a melt consisting essentially of MgO, Al2O3, and SiO2, quenching the melt to a solid glass, and then heating the solid glass to crystallize such oxides to a cordierite crystalline structure in the presenc
In a process for producing a cordierite glassceramic by fusing a mixture of ingredients to form a melt consisting essentially of MgO, Al2O3, and SiO2, quenching the melt to a solid glass, and then heating the solid glass to crystallize such oxides to a cordierite crystalline structure in the presence of a glassy phase; the improvement of increasing the amount of cordierite crystalline structure formed and reducing the amount of glassy phase obtained, comprising: admixing with said mixture or glass at any time prior to such heating step a nucleating agent in a relatively small amount of about 0.5% to about 3%, based on the weight of said solid glass, said agent consisting essentially of a metal Compound, the metal of said compound being selected from a class consisting of Mo, Ta, Zr, Nb, Ti, Li, As and mixtures thereof, and said compound of the metal being selected from the class consisting of the metal itself, an oxide of the metal, a compound convertible to the oxide by heat, and lithium fluoride, comminuting said solid glass to an average particle size no greater than about minus 325 U.S. Standard sieve to provide substantially increased surface area, heating said particles and nucleating agent to a nucleating temperature and forming a plurality of sites for crystallization of said comminuted glass to a cordierite glass-ceramic by the combination of said relatively small amount of nucleating agent and said increased surface area, and then heating the particles and agent at a higher temperature to promote crystallization and form a cordierite glass-ceramic containing at least 80% by weight of a cordierite crystalline structure corresponding to 2MgO.2Al2O3.nSiO2, n being a whole number within the range of 5 to 8, said glass-ceramic having a coefficient of thermal expansion less than 1.60 ×106 inch/inch/° C from room temperature to 600°C as determined by the Orton dilatometer.
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