High-temperature creep and corrosion resistant nano-dispersed ferritic/martensitic (F/M) alloys (such as a T91 steel), or other 'the oxide dispersion strengthened (ODS) steels', are under consideration for nuclear applications because of their high-temperature mechanical properties. They consist typically of a high-chromium steel structure dispersed and reinforced by a dispersion of nano-sized rare-earth metal oxides, typically yttrium oxide (Y2O3). In this study, the production of ODS based on T91 is examined by adding a 0.3 wt% colloidal Y2O3 dispersion to a T91 steel melt in combination with metallic yttrium (YM). The production of the following systems is evaluated: T91-Y2O 3, T91-YM and T91-YM-Y2O 3. At first, it was found that when YM is added to a steel melt, internal oxidation occurs. Furthermore, it was shown that the T91 system with addition of Y2O3 in combination with rare-earth metal YM, creates a homogeneously dispersed ODS T91 material. Moreover, the role of YM as a possible surface active element lowering the surface tension at the contact interface is studied. High-temperature contact angle wetting tests between Y2O3 ceramic substrates in contact with an T91 and a [T91+YM] melt, combined with auger-electron spectroscopy (AES), indicate the influence of YM on the surface activity of Y2O3 in contact with T91. After YM addition, the contact angle between T91 and the Y2O3 substrate lowers down to angles below 90°.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Process Chemistry and Technology
- Surfaces, Coatings and Films
- Materials Chemistry