Abstract: The present invention provides substantially spherical composite ceria/titania particles, a method of forming the same, and chemical mechanical polishing compositions comprising such particles. The substantially spherical particles include a substantially crystalline core portion including one or more crystallites having a cubic lattice structure including Ce(1-x)Ti(x)O2, where x is <0.25, and a substantially amorphous cladding covering at least a portion of the substantially crystalline core portion, the substantially amorphous cladding including Ti(1-y)Ce(y)O2, where y is ?0.50. The method of forming the particles includes combusting an organic solvent including a cerium salt of a carboxylic acid and a titanium (IV) chelate in a combustion supporting gas and collecting agglomerates comprising two or more substantially spherical particles.

Abstract: A transparent yttrium aluminum garnet precursor composition is provided that includes a plurality of calcined particles of yttrium aluminum oxide having a mean particle domain size of between 10 and 200 nanometers and a predominant hexagonal crystal structure. High levels of YAG transparency are obtained for large YAG articles through control of the aluminum:yttrium atomic ratio to 1:06±0.001 and limiting impurity loadings to less than 100 ppm. The composition is calcined at a temperature between 700° Celsius and 900° Celsius to remove organic additives to yield a predominant metastable hexagonal phase yttrium aluminum oxide nanoparticulate having an atomic ratio of aluminum: yttrium of 1:0.6±0.001. With dispersion in an organic binder and a translucent YAG article is formed having a transmittance at a wavelength of 1064 nanometers of greater than 75%.

Abstract: A composition is provided that includes a plurality of calcined particles of terbium aluminum oxide having a mean particle domain size of between 30 and 600 nanometers. A translucent article having a surface includes polycrystalline terbium aluminum garnet having a mean grain size from 1 to 10 microns and light scattering inclusions of aluminum-rich oxide and/or terbium-rich oxide that are present at less than 2 surface area percent of the surface. A process for forming such an article involves sintering the above provided composition at a temperature between 1500° C. and 1700° C. to yield a sintered article. The article has improved translucency and even transparency as sintering is performed under vacuum at a temperature between 1610° C. and 1680° C. Hot isostatic pressing alone or in combination with article polishing also improves article translucency.