Barium titanate precursors with Ba/Ti ratio 2:9 and 1:s were prepared by first hydrolyzing titanium alkoxide and then mixing the resulting titania sol with a barium alkoxidemethanol solution. After drying, the xerogels of the precursors of barium titanates were sintered at temperatures from 700°C (4 h) to 1200°C (110 h or longer). Characterization of the product was performed using X-ray diffraction and laser Raman spectroscopy. At 700"C, BaTi5OI1 was formed from the 1:5 precursor and a two-phase mixture of BaTizOs and BaTiSOII was formed from the 2:9 precursor. After prolonged heating at 1200°C, the latter mixture converted to a single-phase material, BazTiPOzo. [

The effect of agglomerate strength on sintered density, was determined for several yttria powders made by intentionally agglomerating 0.1‐μm, monodisperse yttrium hydroxycarbonate precursor spheres and calcining separate portions of the precursor at different temperatures to vary the strength of the intraagglomerate bonds. In this way, the effects of differences in particle morphology and other characteristics among the powders were minimized and the effect of agglomerate strength could be seen more clearly. The sintered density of the yttria powders decreased with increasing agglomerate strength, and even a small fraction of unbroken fragments of agglomerates in the pressed powder caused a substantial decrease in the sintered density.

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