Abstract
This work reports the formation of self-organized Zircaloy-4 (Zr-4) oxide nanotubes in viscous organic ethylene glycol (EG) electrolyte containing a small amount of fluoride salt and deionized (DI) water via an electrochemical anodization. The structure, morphology, and composition of the Zr-4 oxide nanotubes were studied using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), EDX, and XPS. SEM results showed that the length of the nanotubes is approximately 13 μm, and TEM results showed that the inner diameter of the Zr-4 oxide nanotubes is approximately 20 nm with average wall thickness of approximately 7 nm. XRD and selected area electron diffraction pattern (SAED) results confirmed that the as-anodized Zr-4 oxide nanotubes have cubic crystalline structure. Both cubic and monoclinic phases were found after annealing of Zr-4 oxide nanotubes. The tubular structure morphology of Zr-4 oxide nanotubes did not remain intact after annealing which is attributed to the elimination of F species from the annealed nanotubes.
Highlights
Zirconium alloys (Zircaloy-2 and Zircaloy-4) are important alloys that are widely used as cladding materials for fuel rods in the light water nuclear reactors due to their low-neutron absorption cross section, high corrosion resistance, high ductility, and adequate hardness during normal operating conditions [1,2,3]
FESEM images of the as-anodized Zr-4 oxide nanotubes prepared in ethylene glycol (EG)-based electrolyte are shown in Figure 1a, b,c
A small variation in the wall thickness of Zr-4 oxide nanotube at the same location can be found in the high-resolution transmission electron microscope (TEM) image (Figure 2b)
Summary
Zirconium alloys (Zircaloy-2 and Zircaloy-4) are important alloys that are widely used as cladding materials for fuel rods in the light water nuclear reactors due to their low-neutron absorption cross section, high corrosion resistance, high ductility, and adequate hardness during normal operating conditions [1,2,3]. It is well known that nanostructured materials possess excellent properties compared to their bulk counterparts because of their high surface-to-volume ratio. The surface-to-volume ratio increases when the size of the materials decreases down to nanometer scale. The enhancement in the critical heat flux (CHF) has been reported when Zr-4 oxide nanostructures were implied in a pool-boiling experiment compared to the bulk materials as a result of good surface wettability [4,5]. The nanostructures exhibit superhydrophilic properties, and, heat transfer coefficient and CHF can be much increased.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
