Investigation of microstructure and Isothermal oxidation resistance of cermet HVOF coated on AISI316L at 900 °C

Abstract

The current paper examines the WCCoCr coatings using HVOF sprayed on AISI316L stainless steel and their oxidation behaviour 50 cycles at 900 °C. Oxidation kinetics was developed by calculating weight changes for uncoated and cermet sprayed samples, and the outcomes were evaluated against uncoated and coated stainless steel. Element mapping, EDS, FESEM, and XRD methods were used to examine uncoated and coated AISI316L oxidation samples. Non-protective oxide scale Fe2O3 is formed and broken due to oxidation in the uncoated sample. The scale's high Fe2O3 content caused considerable weight gain in uncoated AISI316L steel substrate. On the other hand, WCCoCr HVOF sprayed samples to have an oxide scale, and it was found that the protective Cr2O3 and WO3 phases offered notable oxidation resistance. The cermet coating reduced the weight gain of AISI316L stainless steel by 73.83%. The HVOF-sprayed AISI316L stainless steel showed superior oxidation resistance to an uncoated specimen.

Keywords

• Isothermal oxidation
• HVOF thermal spraying
• AISI316L
• XRD, SEM/EDS