LnPO4·nH2O particles (Ln = La, Nd, Sm, Eu, Gd, Tb, Ho, Yb, Y) were prepared by homogeneous precipitation from hydrothermal reactions of Ln(edta)- and PO4 3- at 120-200°C and pH 3.0-8.5. Four different types of LnPO4·nH2O, monazite LnPO4·nH2O (Ln = La, Nd, Sm), rhabdophane LnPO4·nH2O (Ln = Nd, Sm, Eu, Gd, Tb, Ho, Y, Yb), xenotime LnPO4·nH2O (Ln = Y, Yb), and amorphous LnPO4·nH2O (Ln = Sm), were obtained depending on the solution pH, concentration, and molar ratios of Ln3+, PO4 3-, edta4-, and Na+, Rhabdophane YbPO4·nH2O which was prepared first contained significant amounts of Na+. Monazite LaPO4·nH2O and rhabdophane LnPO4·nH2O (Ln = Tb, Ho) consisted of a monodispersed spherical particles 0.5-2 μm in diameter, whereas rhabdophane YPO4·nH2O consisted of monodispersed rodlike particles 1-2 μm in length and 0.1-0.2 μm in diameter. Preparation by homogeneous precipitation under hydrothermal conditions using Ln(edta)- chelates has resulted in the discovery of a new synthesis route for rhabdophane LnPO4·nH2O (Ln = Ho, Yb, Y).
|Number of pages||5|
|Journal||British Ceramic Transactions|
|Publication status||Published - 1995 Jan 1|
ASJC Scopus subject areas
- Ceramics and Composites