Different Fe(Al) transition coatings on the performance of Al2O3 coating

Abstract

Three kinds of Al2O3-based tritium permeation barriers with different Fe(Al) transition layers, namely, FeAl/Al2O3, FeAl2/Al2O3 and Fe3Al/Al2O3 coatings were prepared on Si substrates using radio frequency magnetron sputtering technology. The microstructure, mechanical properties, and electron-irradiation resistance of the coatings were investigated systematically to explore the effect of Fe(Al) transition layers on the growth and performance of the Al2O3 coatings. These different coatings were fabricated successfully on Si substrates, while FeAl, FeAl2 and Fe3Al transition layers exhibited a columnar grain structure and the Al2O3 coatings were composed of amorphous and γ-Al2O3 crystalline phases. FeAl and Fe3Al transition layers enhance the formation of γ-Al2O3 crystalline phase, whereas the surface of FeAl2 transition layer is mainly amorphous Al2O3. The FeAl2/Al2O3 coating exhibits the highest adhesive force of 49.75 N among the three samples, and the adhesive forces of the FeAl/Al2O3 and Fe3Al/Al2O3 coatings are 37.75 N and 47.4 N respectively. The surface roughness values of the FeAl/Al2O3, FeAl2/Al2O3 and Fe3Al/Al2O3 coatings are 3.483 nm, 1.042 nm, 4.565 nm, while the hardness values of three samples are 4199 MPa, 6812 MPa, 4796 MPa, respectively. The surface roughness of the FeAl/Al2O3 and Fe3Al/Al2O3 coatings decreased, but the surface roughness of FeAl2/Al2O3 increased after electron irradiation tests. Moreover, the hardness of all three samples was reduced after electron irradiation. These results provide a reference for further studies of the Fe(Al)/Al2O3 coating.