THERMAL CHARACTERIZATION AND CRYSTAL-STRUCTURE OF AN ELECTRORHEOLOGICAL MATERIAL - COMPLEX STRONTIUM-TITANATE

A new type of anhydrous complex strontium titanate (STO) electrorheolo gical fluid (ERF) material is obtained, which demonstrates a good elec trorheological (ER) character even at lower applied electric held. Its shear stress is about 8 kPa at electric field of 2.4 kV/mm. The curre nt density is only 1.6 mu A/cm(2) leaking through the fluids. Some add itive in our samples prevents sedimentation. The shear stresses vary o nly slightly in a wide temperature range. The thermal characteristics of the solid phase STO including the heat capacity and thermal stabili ty were investigated. The value of the activation energy of crystalliz ation was derived to be about 100 kJ/mole. The crystal structure of Y- doped STO was refined by the Rietveld method. Y3+ substitutes for Sr2 in the 1(a) position of space group Pm3m.