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 ℃curred through interdiffusion between the coating and the substrate as follows. The oxidation at 700 ℃ changed the coating to (α-Al2O3 scale)/(α-Al2O3, Al13Fe4, Al5Fe2)-mixed layer)/(Al5Fe2 layer)/(AlFe layer)/(AlFe3 layer)/(α-Fe(Al) layer). The oxidation at 800 ℃ changed the coating to (α-Al2O3 scale)/((α-Al2O3, Al5Fe2)-mixed layer)/(Al5Fe2 layer)/(AlFe layer)/(AlFe3 layer)/(α-Fe(Al) layer). The oxidation at 900 ℃ changed the coating to (α-Al2O3 scale)/((α-Al2O3, AlFe)-mixed layer)/(AlFe layer)/(AlFe3 layer)/(α-Fe(Al) layer). The oxidation at 1000 ℃ changed the coating to ((α-Al2O3, Fe2O3)-mixed layer))/(AlFe3 layer)/(α-Fe(Al) layer). |
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Key Words |
hot dipping, aluminizing, P22 steel, oxidation |
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