Solubility Limits of α'‐SiAION Solid Solutions in the System Si,Al,Y/N,O

Abstract

The solubility limit of α'‐SiAION solid solutions on the Si 3 N 4 ─YN:3AIN composition join in the system Si 3 N 4 ─YN─AIN has been determined at 1800°C. The end members of these solid solutions are Y 0.43 Si 10.7 Al 1.3 N 16 and Y 0.8 Si 9.6 Al 2.4 N 16 . Unit‐cell dimensions of the α'‐SiAION solid solutions in the system Si,Al,Y/N,O can be expressed as follows: a o (Å) = 7.752 + 0.045 m + 0.009 n , c o (Å) = 5.620 + 0.048 m + 0.009 n , where the α'‐SiAION solid solution has the formula Y x Si 12‐( m+n ) Al m+n N 16‐ n O n . The single‐phase boundary of the solid solution α'‐SiAION on the composition triangle Si 3 N 4 ─YN:3AIN─AIN:Al 2 O 3 is delineated. The present paper also reports the phase relationships involving α'‐SiAION.