| In this thesis, lead scandium tantalate-lead titanate (1-x) Pb(Sc1/2Ta1/2)O3-xPbTiO3 (abbr. as PSTT(100x) in the following) relaxor ferroelectric ceramics were prepared by the processing of the electronic ceramics using metal oxides. The crystallization, microstructures, chemical compositions and valence states, and so on, were systematically characterized by means of analysis techniques, such as XRD, SEM, EDAX, XPS, RAMAN and so on. The electrical properties of PSTT(100x) ferroelectric ceramics, including the dielectric constant dependence of temperature, compositions and frequency, and the relationship between dielectric loss and frequency, were measured and analyzed. The mainly research work of the thesis includes the following contents:1. The progresses of research on ferroelectric materials were summarized. The properties and applied fields of relaxor ferroelectric ceramic materials were outlined, and several famous theoretical models explaining the origins of relaxation of ferroelectrics were thoroughly introduced, and the order-disorder transformation theory as one of the concerns of ferroelectric physicists was pointed out.2. The structural characteristics, dielectric properties, ferroelectric properties and pyroelectric properties of lead scandium tantalite Pb(Sc1/2Ta1/2) O3 (abbr. as PST in the following) ceramics were summed up. The preparing process of PST ceramics and the phase diagram and structures of PSTT(1000x) ceramics were introduced.introduced.3. PSTT(100x) relaxor ferroelectric ceramics with high perovskite phase were prepared by a one-step-method. XRD analytical technique was used to quantitatively calculate the volume fraction of perovskite phase of PSTT(100x) ceramics. The results showed that the percent of perovskite phase of PSTT(100x) ceramics prepared by the one-step-method could be up to 100%. The preparing process of one-step-method was simple and advantageous to be generalized in industrialized production.4. The features of the growing kinetics of relaxor ferroelectric ceramics were studied. A forming index of the perovskite structure F was defined for the first time in this thesis, which could show whether a compound could be easily prepared with ABO3-type perovskite structure. The theoretical values accorded well with experimental results.5. SEM micrographs showed that crystalline properties of PSTT(100x) ceramics were good, the interface of crystal grains was clear and crystal grains had a full crystal grain forming. The percentage of the four main elements Pb, Sc, Ta, and Ti in PSTT(100x) ceramics were semi-quantitatively calculated by the EDAX technique. The results showed that the percentage of Pb and Ti elements in PSTT(100x) ceramics approached the theoretical value and the percentage of Sc and Ta elements had bigger deviation from theoretical values. Maybe there were some Ta-rich or Sc-rich micro-domains in PSTT(100x) ceramics.6. The electrical measurement showed that the Curie temperature of PSTT(100x) relaxor ferroelectric ceramics prepared by the one-step-method was higher than that prepared by the two-step-method. The morphotropic phase boundary of PSTT(100x) relaxor ferroelectric ceramics by the one-step-method lied in the composition range about x=0.4-0.45.The thermal hysteresises of PSTT(25), PSTT(35), PSTT(40) and PSTT(45) ceramics were measured in our experiment, and it was found that PSTT(35) ceramics possessed the smallest thermal hysteresis.7. XPS analyses indicated that the chemical states of Sc, Ta and Ti in PSTT(100x) ceramics before and after Ar+ etching are +3 ,+5 and +4, respectively. The peak of Pb4f before etching was analysed, and the results showed the chemicalstate of Pb on the surface of PSTT(100x) ceramics was +2. The detail scanning of Pb4f peaks after etching was decomposed, and the results indicated that there were Pb2+ and free Pb in PSTT(100x) ceramics, and the possibility of existing free Pb in PSTT(100x) ceramics was discussed.8. Raman analyses i...
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