Characterization of High-Mn-Cr Austenitic Steel Powder Fe-19Mn-18Cr-C-N

Paper i proceeding, 2011

High strength Mn-Cr-austenitic stainless steel offers an appropriate and efficient alternative to Nibased austenitic steel. However, high oxygen affinity of manganese (Mn) and chromium (Cr) entails challenges during manufacturing, handling and further consolidation of Cr- and Mn-rich steel powder. Thus, the composition of the surface of highly alloyed powder is the key parameter that determines powder properties and usefulness. The surface layer of the gas-atomized high-strength austenitic steel Fe-19Mn-18Cr-C-N powder was studied by means of surface analytical techniques (XPS and HR-SEM combined with EDX). The XPS-study indicates the presence of relatively large manganese-rich oxide islands surrounded by a homogeneous iron-based thin oxide layer on the powder surface. Up to 7 nm a zone enriched in chromium in oxide state is observed. HR-SEM images in combination with EDX verify the presence of large Mn-based oxide particulates on the powder surface. Obtained results emphasize the substantial effect of a high manganese content on the surface composition.