The effect of surface condition and cold work on the sulphidation resistance of 153MA at 700°C

Abstract

The normal grain sized 153MA-sample experienced an almost linear weight gain curve in the sulphidizing environment while modified materials, with a finer grain size or cold worked structure, displayed more parabolic behaviour and lover weight gains. These effects may be related to more effective Cr-diffusion in the modified samples with a higher Cr-grain boundary diffusion in the fine grain-sample and a higher Cr-bulk diffusion rate in the cold worked sample. The sand blasted sample performed exceedingly well with a thin protective oxide layer compared to the etched and ground samples which both suffered significant weight loss and spalling. The deformed surface structure on the sand blasted sample enhances the Cr-bulk diffusion thus promoting a protective Cr-rich oxide formation.