Phase structure of sputtered Ta coating and its ablation behavior by laser pulse heating (LPH)

Abstract

Abstract Phase structure of sputtered Ta coating in the negative glow space and LPH effect were explored. The whole coating/substrate system is substrate → physically gas-absorbed Fe surface → oxygen-enriched TaOx layer → amorphous Ta → α and β dual phase → single α phase. After LPH course, microstructure of Ta coating shows intact, only a few cracks emerge after 100 laser pulses, exhibiting thin HAZ but thick Fe/Ta ICZ, without martensitic transformation. For the electrodeposited Cr coating, continuous thermal stresses produce many extra micro-crack, substrate oxidation and martensitic transformation, leading to crack propagations and final bulk delamination, without any ICZ.