Phase Relations in the System Al ₂ O ₃ –B ₂ O ₃ –Nd ₂ O ₃

Abstract

The phase relations at a temperature below “subsolidus” in the system Al 2 O 3 –B 2 O 3 –Nd 2 O 3 are reported. Specimens were prepared from various compositions of Al 2 O 3 , B 2 O 3 , and Nd 2 O 3 of purity 99.5%, 99.99%, and 99.9%, respectively, and fired at 1100°C. There are six binary compounds and one ternary compound in this system. The ternary compound, NdAl 3 (BO 3 ) 4 (NAB), has a phase transition at 950°C ± 15°C. The high‐temperature form of NAB has a second harmonic generation (SHG) efficiency of KH 2 PO 4 (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.