The Al ₂ O3‐Nd ₂ O ₃ Phase Diagram

Abstract

A tentative phase diagram for the system Al 2 0 3 ‐Nd 2 O 3 is presented. Three compounds were obtained: a β ‐A1 2 O 3 ‐type compound, the perovskite NdAlO 3 , and Nd 4 Al 2 O 9 . The perovskite melts congruently (mp 2090°C), and the two other compounds exhibit incongruent melting behavior: β ‐Nd/Al 2 O 3 , mp 1900°C; Nd 4 Al 2 O 9 , mp 1905°C. Two eutectics exist with the following compositions and melting points: 80 mol% Al 2 O 3 , 1750°C; 23 mol% Al 2 O 3 ,1800°C. Nd 4 Al 2 O9 decomposes in the solid state at 1780°C.