The effects of re-firing process under oxidizing atmosphere and temperatures on the properties of strontium aluminate phosphors

Inorganic phosphorescent pigments have a very wide application, consisting of ceramic decoration and glazes. Therefore, in the present study 3 different commercially available strontium aluminate phosphors (coded Phosphor A, B and C) emitting yellowish-green light were investigated to determine their behaviour when re-fired under oxidizing atmosphere. The phosphors were re-fired at 10 different temperatures and consequent effects were studied. All the samples were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), laser particle size, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and fluorescence spectrometer analysis. It was found that firing them under oxidizing atmosphere strongly affected their phosphorescence abilities especially over 800–900 °C, because doped europium ions (Eu2+) in their structures are oxidized to Eu3+. It was also concluded that the phosphor powders clumped as the temperature rose, leading to their particle size distributions to change.