Abstract:The oxidation behaviors of Y-Cr-Al coatings by pack cementation process with different Al content were investigated. The results show that the coating with 2% Al content in the pack has a three-layer structure, while the coatings with 2.5% and 3% Al content have two layers. And the main phases in the coating with 2% and 3% Al content are α-Cr and NiAl, respectively. But the main phases in coating with 2.5% Al content is NiAl with several Cr-rich particles and solid solution Cr atoms in the coating. The oxidation test demonstrates that the coated specimen with 2% Al content has the poorest oxidation resistance, but the one with 2.5% Al content has a favorable oxidation resistance.