High temperature oxidation resistance of 316 stainless steel doped with Yttrium using intense pulsed plasma beams

Doping stainless steels or iron chromium alloys with oxygen reactive elements like Y and rare earth elements (REE) like Ce, La, Er and others improves their oxidation resistance at high temperature.
There are numerous methods of incorporating REE into steel by surface treatment, e.g.: ion implantation, metalo-organic, chemical vapour deposition, sol-gel coating, pack cementation, screen-printing, molten-salt electrodeposition.
Recently we undertook an attempt to incorporate REE into steels using a new approach based on the use of high intensity pulsed plasma beams (HIPPB). The characteristic feature of this method rely upon the fact that the REE elements are alloyed into the near-surface region of the substrate in its transient liquid state. The preliminary results obtained on AISI 316L steel samples doped with Ce-La in this way and then oxidized in air for 80 hours at 1000°C were encouraging as regards the scales which were thinner, more compact and well adhered.
In the present work we report on the use of yttrium as an active element incorporated into 316 stainless steel using HIPPB. The surface modification of treated samples was performed using 3 pulses with their energy density of 2 Jcm-2 each. Nitrogen was used as a working gas. The yttrium doses accumulated in stainless steel range from 2.34e16 to 1.28e17 cm-2.
The samples are examined by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), X-ray diffraction (XRD) and crucially important Rutherford Back Scattering (RBS) measurements and subjected to oxidation in air at a temperature of 1000°C for a period of 100 h.