الفهرس 
Theoretical and fundamentalsOnly 14 pages are availabe for public view
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Abstract
Semiconducting Ba-titanate has been used as a thermistor because of the PTCR anomaly and as a barrier-layer capacitor and a boundary-layer ceramic capacitor because of its ferroelectricity. The present work was performed with the object of investigating the effect of rare earth cations, coinage materials and gamma radiation on the physico-chemical properties of Ba-titanate ceramic dielectrics. For this purpose, the procedure of investigations comprises the following investigational 1-ines : 1. preparation of pure and various doped Ba-titanate. 2. X-ray diffraction studies. 3. True and bulk density studies. 4. Microscopic examinations of the sintered bodies. 5. Mechanical strength (crushing strength) examinations. 6. Solid electronic absorption spectra studies. 7. Solid.infrared (IR) absorption spectra studies. 8. Thermogravimetric analysis (TGA). 9. Differential scanning calorimetry (DSC). 10. The temperature dependence of DC-electri-cal conductivity. 11.. I-V characteristi-cs. 12. The temperature dependence of dielectric constant. In the present thesis, Ba-titanate was prepared by the usual solid state reaction of BaCO 3 and Ti03 (1:l)and sintering technique (ll!B•‹Cfor 7 hrs). To get modified Ba-titanate sampels, different percentages of rare earth oxides (La2O3, La203+ IigB03, SII-I .,~:~’,l ’bOx and 110~0,~a)n d coinage materials (Cu,Ag and PtCI2) were added to Batitanate ceramics, the mixture was sintered at 1150•‹C for 6 hrs whereas mixtures of Ba-titanata and (La;!O + 3 H 3 BO ) were sintered at 500•‹C and 1000•‹C. T o evaluate 3 the effect of %-irradiation on the prepared ceramic samples, some of them were exposed to an absorbed gamma 7 radiation dose of 3.5~10 rad.