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SEM top-view (first row) and cross-section (second row) images of the Nb 0.13 (a), Nb 0.19 (b), Nb 0.25 (c), Nb 0.31 (d) and Nb 0.37 (e) thin films, respectively.
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Multicomponent as well as high-entropy-based nitrides have received increasing interest in the field of materials science and engineering. The structural characteristics of these compounds result in a mix of covalent, metallic, and ionic bonds that give rise to a number of attractive properties including high hardness, electrical and thermal conduc...
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... the films, given the high uncertainty associated with EDS measurements of nitrogen concentrations. The target power and atomic composition estimated by means of EDS measurements are given for each component in Table 1. Furthermore, all the films exhibited a similar NaCl-type fcc phase structure with a distinct (200) Bragg peak at ∼41° (see Fig. S1 in the Supporting Information ...
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... top-view SEM images in Fig. 1 (first row), show that the thin films with different Nb concentrations all exhibited a surface morphology with fine grains with a diameter of ∼20 nm. All thin films showed a dense nanocolumnar structure in the SEM cross-section images and an average thickness of ∼500 nm (Fig. 1, second row). This microstructure of the films was ...
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... top-view SEM images in Fig. 1 (first row), show that the thin films with different Nb concentrations all exhibited a surface morphology with fine grains with a diameter of ∼20 nm. All thin films showed a dense nanocolumnar structure in the SEM cross-section images and an average thickness of ∼500 nm (Fig. 1, second row). This microstructure of the films was optimized by substrate biasing based on the results of a previous study [28] as it was important to work with dense thin films in the corrosion studies. Previous corrosion studies on multicomponent AlCrNbYZrN thin films have shown that a higher corrosion resistance was observed for ...
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... samples scanned for higher potentials, see paragraph 3.2.2.). Subsequent to the polarization experiments between − 0.7 and 0.45 V vs. Ag/AgCl (3 M NaCl), XPS was used to probe the surface composition of both Nb 0.31 films (Fig. 8b), and the thicknesses of the oxide layers were also determined by TEM (Fig. 9). The high-resolution XPS spectra (Fig. S10) showed that a mixture of oxides was present on the surface of the films and that the peaks could be assigned to Nb 2 O 5 , ZrO 2 , TiO 2 and Ta 2 O 5 , in agreement with the results for the pristine films (Fig. 2). The TEM results indicated that the average oxide layer for the Nb 0.13 film obtained without any cathodic pre-treatment ...
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... about ∼2.9 nm (Fig. 9). The latter finding is in accordance with the larger oxidation current seen in the polarization curve for the cathodically pretreated film (Fig. 8a). The limited growth of the oxide layer during the scan up to 0.45 V vs. Ag/ AgCl (3 M NaCl) explains why nitride peaks also could be observed in the XPS high-resolution spectra (Fig. S10) since the probing depth of the XPS technique was about 5-10 nm ...
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... seen in the Nyquist plots in Fig. S11a, a capacitive-like behavior was seen before and after the recording of the polarization curves in agreement with the results for the pristine Nb 0.31 film. The inset of Fig. S11a shows the impedance values for the Nb 0.31 films at a higher magnification. The electronic resistance of the films before and after the polarization to 0.45 V ...
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... seen in the Nyquist plots in Fig. S11a, a capacitive-like behavior was seen before and after the recording of the polarization curves in agreement with the results for the pristine Nb 0.31 film. The inset of Fig. S11a shows the impedance values for the Nb 0.31 films at a higher magnification. The electronic resistance of the films before and after the polarization to 0.45 V vs. Ag/AgCl (3 M NaCl) was estimated following the approach applied for the pristine materials (see Section 2.1). From the data presented in Fig. S11b, minor variations in the ...
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... pristine Nb 0.31 film. The inset of Fig. S11a shows the impedance values for the Nb 0.31 films at a higher magnification. The electronic resistance of the films before and after the polarization to 0.45 V vs. Ag/AgCl (3 M NaCl) was estimated following the approach applied for the pristine materials (see Section 2.1). From the data presented in Fig. S11b, minor variations in the high frequency resistance are seen, suggesting a negligible effect of the anodic polarization treatment (up to 3.0 V vs. Ag/ AgCl (3 M NaCl)) on the electronic properties of the ...
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... that the ECSA value should be affected by changes in the surface morphology of the films (e.g., variations in the porosity). A change in the ECSA should result in a change in the capacitance, C, of the interface since the capacitance should be proportional to the ECSA. The capacitance values were extracted from the EIS data presented in Fig. 10, using the approach reported by Pickup et al. [42,43]. This approach involves plotting the parameter − 1/(2πfImZ) (representing the capacitance of the interface) vs. ReZ. From such plots, the limiting capacitance value, C lim , can be approximated by the plateau of the − 1/(2πfImZ) parameter often seen in the low frequency range. The C ...
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... means that the entire ECSA is probed. In this approach, it is assumed that the interface exhibits a blocking behavior at low frequencies and that the reactance of the system therefore is solely attributed to the double layer capacitance. This assumption should be valid here given the phase angle values (> 85°) seen in the Bode phase plots in Fig. 10. From the results presented in Figs. S12 and S13, it can be deduced that C lim values for the Nb 0.13 and Nb 0.25 films decreased by a factor of about four as a result of their scanning up to 3.0 vs. Ag/AgCl (3 M NaCl), but for the Nb 0.31 films scanned up to 0.45 V vs. Ag/AgCl (3 M NaCl) a slight increase by a factor of ca. 1.2 was ...
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