PHASE-RELATIONS IN THE SYSTEM AL2O3-B2O3-ND2O3

The phase relations at a temperature below "subsolidus" in the system Al2O3-B2O3-Nd2O3 are reported. Specimens were prepared from various compositions of Al2O3, B2O3, and Nd2O3 of purity 99.5%, 99.99%, and 99.9%, respectively, and fired at 1100-degrees-C. There are six binary compounds and one ternary compound in this system. The ternary compound, NdAl3(BO3)4 (NAB), has a phase transition at 950-degrees-C +/- 15-degrees-C. The high-temperature form of NAB has a second harmonic generation (SHG) efficiency of KH2PO4 (KDP) of the order of magnitude of the form which has been used as a good self-activated laser material, and the low-temperature form of NAB has no SHG efficiency.