Synthesis and Fluorescence Properties of Europium-Lanthanum-Calcium Orthophosphates and Condensed Phosphates

Abstract

<p class="MsoNormal"> <span lang="EN-US">Mixtures of lanthanum oxide, europium oxide, calcium carbonate, and phosphoric acid were heated with various ratios of P/(Eu</span><span lang="EN-US"> </span><span lang="EN-US">+</span><span lang="EN-US"> </span><span lang="EN-US">La</span><span lang="EN-US"> </span><span lang="EN-US">+</span><span lang="EN-US"> </span><span lang="EN-US">Ca) and La/Ca. Europium ratio was settled at Eu/(Eu</span><span lang="EN-US"> </span><span lang="EN-US">+</span><span lang="EN-US"> </span><span lang="EN-US">La</span><span lang="EN-US"> </span><span lang="EN-US">+</span><span lang="EN-US"> </span><span lang="EN-US">Ca)</span><span lang="EN-US"> </span><span lang="EN-US">=</span><span lang="EN-US"> </span><span lang="EN-US">0.03. The obtained phosphates were estimated using X-ray diffraction (XRD) patterns, Fourier transform infrared spectroscopy (FT-IR) spectra, and scanning electron micrograph (SEM) images. The fluorescence spectra and resistance against hydrofluoric acid were estimated as functional properties of these phosphate materials. The mixture of lanthanum and calcium phosphates were formed from XRD patterns and IR spectra. Samples prepared in P/(Eu</span><span lang="EN-US"> </span><span lang="EN-US">+</span><span lang="EN-US"> </span><span lang="EN-US">La</span><span lang="EN-US"> </span><span lang="EN-US">+</span><span lang="EN-US"> </span><span lang="EN-US">Ca)</span><span lang="EN-US"> </span><span lang="EN-US">=</span><span lang="EN-US"> </span><span lang="EN-US">2 and 3 had large particles in SEM images. The condensed phosphates showed a strong peak at 615 nm and high resistance against hydrofluoric acid.</span> </p&gt