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 (Y 3 Al 5 O 12 ) and cordierite (Mg 2 Al 4 Si 5 O 18 ) powders. Long-chain polymers such as polyvinyl alcohol (–[CH 2 –CHOH]- n or PVA) or polyethylene glycol (H[O–CH 2 –CH 2 ] n OH 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.