Compositions in the system Th02-Y01 6 were coprecipitated as oxalates and converted to oxides. Disks were pressed and sintered in oxygen at 1400" to 2200°C. Densities of the sintered disks were 96 to 98% of theoretical. Solid solutions with the fluorite-type structure were formed up to 20 to 25 mole yo YOl,s at 1400OC and up to 45 to 50 mole ' % Y O 1 .~ at 2200°C. Density data showed that these solid solutions correspond to Thl-,Y,Oz-o.s,, having a complete cation sublattice filled by T h 4 + and Y3+ ions, and vacancies in t h e anion sublattice. The observed increase in electrical conductivity with increase in Y01.5 content is consistent with charge transport by oxygen ions through a vacancy mechanism. Approximately 7 mole % T h o 2 is soluble in Y01.5 at 2200°C. Density results indicate an anion interstitial structure for the Yz03 phase. Transference number measurements indicate that the electrical conductivities are only partly due to ions.

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The formation of a complete series of solid solutions in the system PbTi03-KNbOs was established by X-ray and dielectric studies. The room-temperature symmetry of the entire system was tetragonal except for compositions containing more than 96 mole yo KNb03, which had orthorhombic symmetry. The axial ratio, c/a, and the ferroelectric Curie temperature decreased from both the end-members. The lowest Curie temperature observed in the system was 175°C for the composition with 80 mole % KNbOR. A generalization has been made on the variation of ferroelectric Curie temperatures with compositions in binary systems of perovskite-type solid solutions with and without a common cation.

An X-ray and dielectric study of three series of PbNbz06-type solid solutions was carried out.The PbNbZOs-type phase was present up to the following limits : (1) (Pbl-,Bi,) (Ti,Nbz-.)Oa,Orthorhombic distortion b / a and Curie temperature decreased with increasing x. Bi4/3-Ti206 was most effective in this respect and Biz, 3-Nb206 had the least influence. The important role played by ions of different valency located on crystallographically equivalent sites is pointed out.

A sample holder is described which has been used for the investigation of dielectric properties of ferroelectric materials from room temperature to over 700°C at frequencies up to 100 kc. It has also been used to observe hysteresis (D-E) loops of ferroelectrics in ceramic and single crystal form.