Preparation of Cerium-Activated GAG Phosphor Powders

An impure-phase usually remains in the product of gadolinium aluminum garnet (GAG) powder as synthesized. In this study, an attempt to prepare a stable GAG pure-phase powder by substituting small cations ( , , or ) at the dodecahedral sites or the substituting the large cation for the sites of the garnet structure was made. Pure garnet-phase GAG powder was formed by calcining at for . It was found that increasing the content in the lattice site of the dodecahedral or increasing the content in the site induces a blue shift in the emission wavelength. The color temperature of the pure (YAG:Ce) phosphor powder formed was lower than that of yttrium aluminum garnet and terbium aluminum garnet (TAG:Ce) phosphors.