Barium titanate and production and process thereof
First Claim
1. A barium titanate comprising at least one element selected from the group consisting of Sn, Zr, Ca, Sr, Pb, La, Ce, Mg, Bi, Ni, Al, Si, Zn, B, Nb, W, Mn, Fe, Cu, and Dy, said at least one element being in an amount of less than about 5 mol %, inclusive of 0 mol %, on the basis of the entirety of BaTiO3,wherein BET specific surface area x, unit:
- m2/g, and the ratio y of the c-axis length, unit;
nm, of a crystal unit lattice to the a-axis length, unit;
nm, of the crystal unit lattice as measured by means of a Rietveld method satisfy one of the following two relations (1) and (2);
(1) y≧
1.01−
(8.8)(10−
6)(x3), wherein x is greater than about 0.1 and not more than 9.7(2) y≧
1.003 and x>
9.7.
1 Assignment
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Accused Products
Abstract
The present invention provides a barium titanate having a small particle size, containing small amounts of unwanted impurities, and exhibiting excellent electric characteristics, which can be employed for forming a dielectric ceramic thin film required for a small-sized capacitor which enables production of a small-sized electronic apparatus; and a process for producing the barium titanate. When a titanium oxide sol is reacted with a barium compound in an alkaline solution containing a basic compound, the basic compound is removed in the form of gas after completion of reaction, and the resultant reaction mixture is fired, a barium titanate having a large BET specific surface area and a high tetragonality content is produced.
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Citations
16 Claims
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1. A barium titanate comprising at least one element selected from the group consisting of Sn, Zr, Ca, Sr, Pb, La, Ce, Mg, Bi, Ni, Al, Si, Zn, B, Nb, W, Mn, Fe, Cu, and Dy, said at least one element being in an amount of less than about 5 mol %, inclusive of 0 mol %, on the basis of the entirety of BaTiO3,
wherein BET specific surface area x, unit: - m2/g, and the ratio y of the c-axis length, unit;
nm, of a crystal unit lattice to the a-axis length, unit;
nm, of the crystal unit lattice as measured by means of a Rietveld method satisfy one of the following two relations (1) and (2);(1) y≧
1.01−
(8.8)(10−
6)(x3), wherein x is greater than about 0.1 and not more than 9.7(2) y≧
1.003 and x>
9.7. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
- m2/g, and the ratio y of the c-axis length, unit;
Specification