ISSN 0862-5468 (Print), ISSN 1804-5847 (online) 

Ceramics-Silikáty 48, (4) 180 - 184 (2004)


CaTiO₃ RELATED MATERIALS FOR RESONATORS
 
Taibi-Benziada Laldja 1, Mezrqua Abderrahmane 2, Von Der Mühll Regnault 3
 
1 USTHB, BP 32 El-Alia, Bab-Ezzouar, 16311 Algiers, Algeria
2 EMP, B.P.17, Bordj-El-Bahri, 16111 Algiers, Algeria
3 IMCB - C.N.R.S., 87 Avenue Albert Schweitzer, 33608 Pessac, France

Keywords: CaTiO₃, Oxyfluorides, Phase transitions, Dielectric characteristics
 

Ceramics of Ca0.95M0.05(Ti0.95Li0.05)O2.85F0.15 (M = Ca, Sr, Pb) are prepared from mixtures of CaTiO₃, MF₂ and LiF powders by sintering at 950°C for 4 hours in free-air. The samples are investigated by X-ray diffraction, scanning electron microscopy , differential scanning calorimetry and dielectric measurements. The phase transitions of pure CaTiO₃ are strongly influenced by the incorporation of the fluoride mixture MF₂ + LiF into the host lattice whereas the orthorhombic symmetry at room temperature is not at all affected by the chemical substitutions Ca–M, Ti–Li and O–F. The dielectric permittivity ε'r and losses tanδ are slightly dependent of temperature between 20°C and 200°C. At room temperature, ε'r is stable over a large frequency range with tanδ < 1%. The Ca0.95M0.05(Ti0.95Li0.05)O2.85F0.15 (M = Ca, Sr, Pb) oxyfluorides are promising materials to manufacture resonators.


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