Solute redistribution during planar growth of intermetallic compound with nil solubility

► Banded structure is observed in directionally solidified Al-11at%Co alloy. ► Planar growth of Al9Co2 is first experimentally confirmed. ► Solute redistribution during planar growth of intermetallics is analyzed. ► A linear equation is obtained to describe solute variation in the liquid. ► Steady state for planar growth of intermetallic compound is analyzed.