Phase relations in the system Y2O3-CaO-B2O3

The subsolidus phase relations of the system Y2O3 -CaO-B2O3 are investigate d by means of X-ray diffraction (XRD) analyses. There are six binary compou nds and three ternary compounds in this system. The phase diagram comprises 13 three-phase regions. The ternary compound CaYBO4 is refined from powder XRD data by the Rietveld method. It has a warwickite-like structure with c ell parameters a=10.4354(3) Angstrom, b=9.6126(2) Angstrom, c=3.5880(1) Ang strom and space group Nam. The rationality of the CaYBO4 structure is exami ned by Brown bond valence model and IR spectra. (C) 2001 Elsevier Science B Y. All rights reserved.