Substitution of Ba for Ca in the Structure of CaAl ₁₂ O ₁₉

Abstract

The effect of Ba 2+ on the crystallization thickness of calcium hexaaluminate ( CA 6 ) along the c axis was studied. The results show that after introduction of Ba 2+ , the CA 6 flake crystals fired at 1600°C become thicker obviously. The structure refinement shows that the structure formula of the doped CA 6 is (Ca 0.973 Ba 0.027 )O·6Al 2 O 3 , indicating Ba 2+ has entered the lattices of CA 6 and substituted Ca 2+ in the mirror layers. The introduction of Ba 2+ results in more defects V A l in spinel block layers in CA 6 , making ions easier to diffuse along c axis and fastening the growing of CA 6 crystals along c axis. Thus, the introduction of Ba 2+ is feasible and advantageous to increase the crystallization thickness of CA 6 along c axis.