[en] A new process for the production of high surface area, high reactivity ceramic oxide powders involves the bonding of metal cations to polymeric polyacrylate chains. This process results in the formation of a gelatinous metal polyacrylate precipitate which can be easily removed from the mother liquor, and then calcined to form a high density ceramic oxide. Using FTIR spectroscopy, the nature of the structural arrangements has been studied for metal complexes in the yttrium, lanthanum, aluminum, cerium, copper, and iron polyacrylates. Interpretation of the infrared spectra indicates that two types of metal complex formation occur in these precipitates, involving bidentate or bridging interactions. The type that is observed for a particular metal ion is dependent on its metal ion size

[en] A new process for the production of fine grained Ba/sub 2/YCu/sub 3/O/sub 7-∞/ material has been studied. The process involves the chelation of the metal ions in solution to an organic acid polymer and subsequent calcination. Using TG, DTG, and X-ray powder diffraction the formation of the 213 phase was investigated. It was determined that the final 213 phase could be formed 50⁰C lower than using a traditional solid state reaction

[en] Thermal cycling of Ba₂YCu₃O_7±x powder under air and nitrogen atmospheres in either a scanning calorimeter or a thermogravimetric analyzer results in alternating oxidation/reduction reactions. Thermal cycling also leads to substantial modifications of the crystallographic unit cell and microstructure. The 440⁰C phase transformation disappears during this process. 3 refs

[en] Thermal diffusivity and conductivity values for several Al₂O₃-SiC whisker composites were determined. The thermal diffusivity values spanned the range from 373 to 1473 K, and thermal conductivity data were obtained between 305 and 365 K. The thermal diffusivity decreased with increasing temperature and increased with SiC-whisker content. An estimate of the thermal conductivity of the whiskers was obtained from the direct thermal conductivity measurements, but attempts to derive whisker conductivity values from the thermal diffusivity data were not successful because the laser flash method lacks the required accuracy and precision. Specimens were subjected to two different thermal quench experiments to investigate the effect of thermal history on diffusivity. In the most severe case, multiple 1073- to 373-K quenches, radial cracks were observed in the test specimens; however, there was no change in diffusivity. The lack of sensitivity to thermal cycling appears to be related to the sample size