الفهرس 
Fibrous materialsOnly 14 pages are availabe for public view
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Abstract
the problem presented i n t h i s thesis i s the study of the electrical properties of an insulating material, namely BaZr02 J doped with different percentages of Li,O ranging from mol $ to L 40 mol 5. The ceramic materials were prepared by the usual solid state react ion of BaCO- and ZrO (1 : 1) i n the temperature range bet- 3 2 ween 1200 - 1400” C. Different percentages of Li 0 were then added 2 to BaZrO, powder, the mixture fired at different temperatures from J 750’ C to 1450’ C; the f i r i n g temperature increasing as the Li20 percentage decreases. The materials prepared were identified by X-ray diffraction patterns. Infrared and ultraviolet absorption spectra were also made, in order to throw light on the manner Li 0 enters the l a t t i c e . 2 The D.C. e l e c t r i c a l conductivity of BaZr03 - Li 0 composit-2 ions, the relation between log CY and T were studied, The former r e l a t ion of contjuc-tivity versus 1/~sh owed ma~maf o r t h e samples containing 3$m01 and 15% mol of Li20 the l a t t e r relation, which i s linear with negative slope is characteristic of semi-conductors. from these relations differences i n the value of log @ between compos2tions having mall and great percentages of Li20 r~ngingfr om 10-l~t o 10 -8 can be detected. The high temperature conductivity i s mainly attributed t o the original l a t t i c e , because a l l impurities are ionized. A t lower temperatures, conductivity i s due t o ionization of impurities which i s characterized by small activation energy.