Abstract
When 2.25Cr-1Mo steel was hot-dip aluminized, a coating consisting of (Al-rich topcoat)/(Al₁₃Fe₄ layer)/(Al₅Fe₂ layer) formed. With increment of oxidation temperature, the transform of Al→Al₁₃Fe₄→Al₅Fe₂→AlFe→AlFe₃→α-Fe(Al)→α-Fe occurred through interdiffusion between the coating and the substrate as follows. The oxidation at 700 ^oC changed the coating to (α-Al₂O₃ scale)/(α-Al₂O₃, Al₁₃Fe₄, Al₅Fe₂)-mixed layer)/(Al₅Fe₂ layer)/(AlFe..... More