The influence of cerium, yttrium and lanthanum ion implantation on the oxidation behaviour of a 20Cr25NiNb stainless steel in carbon dioxide at 900–1050°C

• Published in: Materials science and engineering 1987-06, Vol.90, p.177-190
• Main Authors: Bennett, M.J., Bishop, H.E., Chalker, P.R., Tuson, A.T.
• Format: Article
• Language: English
• ISSN: 0025-5416
• DOI: 10.1016/0025-5416(87)90210-2

The influence of the implantation of 10 17 Ce + cm −2, 10 17 La + cm −2 and 10 −2 on the oxidation behaviour of 20Cr25NiNb stainless steel (where the composition is in weight per cent) in carbon dioxide has been examined at temperatures between 900 and 1050°C. The oxidation kinetics during isothermal exposures of about 250 h duration were followed using a controlled-atmosphere microbalance, and spallation during subsequent cooling to room temperature was assessed. The composition and microstructure of the multicomponent scales formed were examined by a range of surface-analytical techniques, with the location of the implanted atoms being established by dynamic secondary ion mass spectrometry. The oxidation of the 20Cr25NiNb stainless steel over this temperature range is characterized by the transition from protective- to non-protective-type behaviour with scale breakdown due to the occurrence of cracking during isothermal oxidation and due to spallation on thermal cycling. By incorporation within the oxide scale, and in particular by segregation to the oxide grain boundaries, the implanted reactive elements extended the temperature range of protective-type behaviour to 1000°C or less, depending on the element, by modifying the initial scale growth mechanism and also the resultant scale microstructure and mechanical properties. Implantation had no significant beneficial influence on the oxidation behaviour of the steel at 1050°C.