Synthesis of oxide powders by way of a polymeric steric entrapment precursor route

A polymerized organic-inorganic complexion route is introduced for the synthesis of yttrium aluminum garnet, YAG (Y₃Al₅O₁₂) and cordierite (Mg₂Al₄Si₅O₁₈) powders. Long-chain polymers such as polyvinyl alcohol (-[CH₂-CHOH]-n or PVA) or polyethylene glycol (H[O-CH₂-CH₂]nOH or PEG) were used as the organic carriers for a precursor ceramic gel. Calcined powders were very porous and homogeneous in distribution of components. Experimental studies by differential thermal analysis and thermogravimetric analysis, x-ray diffraction, solid-state nuclear magnetic resonance, and Fourier transform infrared spectrometry indicated that metal-ion chelation is not the primary mechanism for obtaining molecularly homogeneous precursor powders. Water-soluble cations of mixed oxides in the PVA or PEG process were sterically entrapped in the entangled network and resulted in fine and pure, mixed oxide powders.