The inflection point at ~400 nm wavelength (~3 eV) in curves means the onset of optical absorption, which is in agreement with the above results. Decomposed Si2p peaks of oxidized PM2000 at 1073 K. XPS spectra in the Mg2p region for treated PM2000 from 1073 K to 1473 K. XPS spectra in the C1s region for treated and as-received PM2000 at various temperatures (a) and decomposed C1s peak of oxidized PM2000 at 1073 K (b). Typical morphology of the surface scales of PM2000 after 7 h exposure at 873 K (a), 1073 K (b), 1173 K (c), and 1473 K (d). 2019 May 18;20(10):2468. doi: 10.3390/ijms20102468. The Al2O3 films growth occurs during alternating exposures to TMA and H2O. First, the ALD growth speed is not constant in each cycle. It is now possible to detect the presence of transition Al2O3 and perhaps their nature on oxide scales formed by oxidation of alumino-former alloys. (ii)The percentage of the thermal α-Al2O3 formation was estimated by XPS analysis as a function of temperature. Through ligand exchange between TMA and surface hydroxyl groups form the bridging oxygen bonds Al-O-Al on the surface and in the meantime release methane molecules. Figure 11 provides the calculated dielectric function spectra of amorphous Al2O3 film with different thickness. Mg doping α-Al2O3 improved densification and elimination of residual porosity . These results have allowed us to determine some characteristic IR and XPS peaks, that is, signatures, for the various transition Al2O3 phases and α-Al2O3. A. Sasse, and H. E. Evans, “Dependence of oxidation behaviour on silicon content of 20%Cr austenitic steels,”, N. Louet, H. Reveron, and G. Fantozzi, “Sintering behaviour and microstructural evolution of ultrapure, J. Chovanec, D. Galusek, J. Ráhe, and P. Šajgalík, “Low loss alumina dielectrics by aqueous tape casting: the influence of composition on the loss tangent,”, V. V. Ivanov, S. Y. Ivin, A. I. Medvedev, S. N. Paranin, V. R. Khrustov, and A. K. Shtol'tz, “Fabrication of Mg- and Ti-doped submicron-grained alpha-alumina-based ceramics,”, T. L. Barr and S. Seal, “Nature of the use of adventitious carbon as a binding energy standard,”, S. Ben Amor, G. Baud, M. Jacquet, G. Nansé, P. Fioux, and M. Nardin, “XPS characterization of plasma-treated and alumina-coated PMMA,”. Concerning the morphology of the oxide obtained at 1473 K, which can be seen in Figure 2(d), the formation of a bulk porous microstructure is observable, with a quite different microstructure in comparison with the a, b, c specimens. Works demonstrate that Mg additions uniformly distributed over a nanometer-sized Al2O3 powder have no effect on the γ to δ phase transition, raise the densification rate in the rapid-sintering stage, and increase the net shrinkage . The FTIR spectrum obtained after oxidation in air for 7 h of a PM2000 sample at 1073 K (Figure 6(b)) differs from the previous one. This work is an original example to compare the results obtained after calcination of Al2O3 hydroxides and oxidation of alumino-formers alloys. SiO2 has a detrimental effect on the Al2O3 densification behavior particularly during the intermediate stage of sintering (from 1473 to 1673 K). Large thin sheets of Sapphire can be made by ribbon growth. It is established by Jellison et al. The surface topography … Bur. Copyright © 2015 K. Djebaili et al. In this work, AFM is used to characterize the surface structure of the amorphous Al2O3 films. FTIR and XPS signatures were obtained for various oxidation temperatures and compared with those known from the literature about calcination of Al2O3 precursors. Peak observed at ~873 cm−1 is due to out-of-plane bending vibration (υ4–) of carbonate. The high prevalence of extended-spectrum β-lactamases (76.3 %) and metallo-β-lactamases (7.3 %) amongst the bacteria Pseudomonas aeruginosa is a critical problem that has set forth an enormous therapeutic challenge. The number of surface activation groups determines the number of molecules per cycle. Before oxidation, at room temperature, native oxide, thin film exists on the alloy surface, with only several nanometers in thickness, and it consists of all the alloying elements as mentioned in literature . This native oxides is Al2O3 and a mixture of oxides as Fe, and Cr. Second, the thickness calculated by SE analysis has about 0.5 nm error. This formula is not limited by the preferential orientation and is valid for an ordinary XRD profile. Review articles are excluded from this waiver policy. The outer surface of the Al2O3 scale formed on PM2000 after 7 h oxidation at 1073 K in air was observed by SEM (Figure 2). Optical Transmission of UV Grade Sapphire and Standard Commercial Grade This low slope is the same as the situation in SE measurement, which also convincingly verifies the reliability of our SE results. Nanoparticles as Anti-Microbial, Anti-Inflammatory, and Remineralizing Agents in Oral Care Cosmetics: A Review of the Current Situation. It can be seen from Figure 1(a) that Si XRD exhibits three diffraction peaks at 61.86°, 66.02°, and 69.16°, respectively. FTIR spectra were obtained using a Perkin-Elmer spectrometer at a resolution of 8 cm, An XPS spectrometer was used to qualitatively and quantitatively verify the composition of the different powder compounds. 2015AA042601), and Shanxi “1331 Project” Key Subject Construction (1331KSC). For single layer film, the amplitude ratio is characterized by the refractive index , while represents light absorption by applying the Fresnel equations. The values of the and parameters from the XRD peak are estimated by Gaussian fitting. Crit Rev Microbiol. Data were collected with steps of 0.021° (2θ). The electrical properties of alumina films were determined by measuring (C–V) and (I–V) characteristics in a metal oxide semiconductor (MOS) structure. Epub 2015 Sep 11. can change your cookie settings at any time. Indeed, the most common technique, the XRD, provides patterns for various Al2O3 which are relatively close to each other. (iv)An XPS spectrometer was used to qualitatively and quantitatively verify the composition of the different powder compounds. The EDS result combined with XRD result confirms that our samples deposited at 200°C is amorphous. Antibiotics (Basel). 2020 Oct 7;8(10):1545. doi: 10.3390/microorganisms8101545. heating it up to the specified temperature at 20 K/min; maintaining it for 7 h at the oxidation temperature; cooling it down rapidly to room temperature (air quench). Sapphire is used for its extreme toughness and strength. In this paper, we report the preparation and characterization of alumina films prepared by both electron beam evaporation and spray pyrolysis method. The hydrodynamic size in Milli Q water and Zeta potential were determined to be 254 nm and +52.2 mV, respectively. The bulk layer plays a key role in the values of Al2O3 samples, and the surface roughness is subordinate. It can be seen that the calculated outcomes fit the experimental points well. Figure 3(a) shows the EDX analysis samples of PM2000 (as-received and oxidized). -, Diagn Microbiol Infect Dis. The decomposition of the C1s signal in the domain (oxidation PM2000 at 873–1473 K) results in too bands (Figures 15(a) and 15(b)). Likewise, the XRD patterns of all deposited films almost completely overlap the Si XRD , and no other peaks are observed, implying the amorphous structure of the obtained samples.
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