Air oxidation behaviour of standard PVD and novel HIPIMS coatings at 750°C for 1000 h

Abstract

High temperature oxidation resistance of Al₂Au and TiAlCr standard PVD coatings and novel nano-structured CrAlYN/CrN coatings developed by HIPIMS technology was studied at 750°C for 1000 h. The results showed better high temperature oxidation resistance offered by HIPIMS coatings where protective oxide scales formed rich in Al and Cr, with lack of spallation and low mass gain during whole test duration was observed. In contrast Al₂Au and TiAlCr coated materials showed thicker oxide scales, the samples coated by Al₂Au and TiAlCr TiAl–8Nb alloy showed poorer corrosion resistance in air than that offered by the uncoated alloy. Post exposure analyses were performed by means of scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS).

Keywords:

• TiAl
• Oxidation
• Coatings
• High temperature
• HIPIMS
• SEM EDS

Acknowledgement

The authors gratefully acknowledge the financial support from The European Union (INNOVATIAL-Project NMP3-CT-2005-515844).