Abstract: In order to prevent BaMgAl₁₀O₁₇∶Eu (BAM) phosphor from thermal degradation, MgF₂ coatings on the surface of BAM were prepared by a sol-gel process. The coatings were characterized by X-ray photoelectron spectroscopy and scanning electron microscopy. The results indicate that BAM is successfully coated with homogenous, close MgF₂ coatings. The photoluminescence and anti-thermal degradation properties of coated BAM were investigated under 254 and 147nm excitations. The optimum anti-thermal degradation properties are obtained at the mass ratio of MgF₂ to BAM 0.2% under 254nm excitation and 0.5% under 147nm excitation, respectively. It is considered that trace MgO formed after baked would cause different optimum coating thicknesses under 254 and 147nm excitations.

Key words: BaMgAl₁₀O₁₇; Eu; thermal degradation; sol-gel process; coating