scholarly journals Effect of Al Addition on the Oxidation Resistance of HfC Thin Films

Coatings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 27
Author(s):  
Aleksander Gaydaychuk ◽  
Stepan Linnik ◽  
Aleksander Mitulinsky ◽  
Sergei Zenkin
Keyword(s):  
Thin Films ◽  
Solid Solution ◽  
Oxidation Resistance ◽  
Mass Gain ◽  
Film Structure ◽  
Sample Mass ◽  
Al Addition ◽  
Oxidation In Air ◽  
Xrd Patterns

In this paper, we focus on the research of Al addition on Hf–Al–C film structure and oxidation resistance. It was found that obtained Hf–A–C films consist of a solid solution of Al in non-stoichiometric cubic HfC and have identical XRD patterns to bcc–HfC. Besides, the Al addition decreases the sample mass gain during oxidation in air at temperatures up to 800 °C. Mass gain for Hf–Al–C was 44.3 and 22.5% less, compared to pristine HfC, at 600 and 800 °C, respectively.

scholarly journals On the Microstructure and Isothermal Oxidation at 800 and 1200 °C of the Nb-24Ti-18Si-5Al-5Cr-5Ge-5Sn (at.%) Silicide-Based Alloy

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 722 ◽  
Author(s):  
Ofelia Hernández-Negrete ◽  
Panos Tsakiropoulos
Keyword(s):  
Solid Solution ◽  
Oxidation Resistance ◽  
Volume Fraction ◽  
Coefficient Of Thermal Expansion ◽  
Cast Alloy ◽  
Isothermal Oxidation ◽  
Valence Electron Concentration ◽  
Scale Spallation ◽  
Substrate Interface ◽  
Oxidation In Air

The research presented in this paper aspired to understand how the simultaneous addition of Ge and Sn in an Hf-free Nb-silicide-based alloy affected its oxidation resistance. Results are presented for the Nb-24Ti-18Si-5Al-5Cr-5Ge-5Sn alloy (at.%) which was studied in the as-cast and heat-treated (1400 °C/100 h) conditions and after isothermal oxidation in air at 800 and 1200 °C. There was macrosegregation in the cast alloy, in which the Nbss formed at a low volume fraction and was not stable after heat treatment at 1400 °C. The βNb5Si3, A15-Nb3Sn, and C14-NbCr2 were stable phases. The alloy did not undergo pest oxidation at 800 °C, and there was no spallation of its scale at 1200 °C. There was enrichment in Ge and Sn in the substrate below the scale/substrate interface, where the compounds Nb3Sn, Nb5Sn2Si, (Ti,Nb)6Sn5, and Nb5Ge3 were formed. After the oxidation at 1200 °C, the solid solution in the bulk of the alloy was very Ti-rich (Ti,Nb)ss. Improvement of oxidation resistance at both temperatures was accompanied by a decrease and increase, respectively, of the alloy parameters VEC (valence electron concentration) and δ, in agreement with the alloy design methodology NICE (Niobium Intermetallic Composite Elaboration). The elimination of scale spallation at 1200 °C was attributed (a) to the formation of Ti-rich (Ti,Nb)ss solid solution and (Ti,Nb)6Sn5, respectively, in the bulk and below the scale, (b) to the low concentration of Cr in the scale, (c) to the absence of GeO2 in the scale, (d) to the formation of αAl2O3 in the scale, and (e) to the presence (i) of Nb5Ge3 below the scale/substrate interface and (ii) of oxides in the scale, namely, SiO2, Al2O3, TiO2, and SnO2, and Ti2Nb10O29,TiNb2O7, and AlNbO4, respectively, with a range of intrinsic thermal shock resistances and coefficient of thermal expansion (CTE) values that reduced stresses in the scale and the substrate below it.

Deposition of ZnS thin films by electron beam evaporation technique, effect of thickness on the crystallographic and optical properties

2019 ◽  
Vol 33 (04) ◽  
pp. 1950034 ◽  
Author(s):  
Bassam Abdallah ◽  
Koutayba Alnama ◽  
Fareza Nasrallah
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Electron Beam ◽  
Film Thickness ◽  
Optical Transmittance ◽  
Electron Beam Evaporation ◽  
Film Structure ◽  
Dielectric Constants ◽  
Glass Substrates ◽  
Xrd Patterns

Deposition of Zinc sulfide (ZnS) thin films on Si (100) and glass substrates has been performed using electron beam evaporation (EBE) method without annealing. Film structure has been analyzed by XRD, while SEM and AFM have been used to explore the films morphology. Raman spectroscopy has been used to confirm film composition. The stoichiometry has been verified by EDX and XPS techniques. XRD patterns indicated that the films possess a polycrystalline cubic structure with orientations along (111) and (220) planes. The crystallinity has been better with film thickness in the 350–1700 nm range while the RMS roughness increases. Optical properties of the grown films were characterized by optical transmittance measurements (UV–Vis). The deduced energy band gap of the films shows a clear reduction from 3.45 eV to 3.36 eV with increasing film thickness. The evolution of refractive index, extinction coefficient, and dielectric constants with thickness has been investigated from transmittance spectra in the 500–1000 nm wavelength range.

Effect of Sputtering Conditions on the Microstructures of YNiBi Thin Film

2013 ◽  
Vol 341-342 ◽  
pp. 149-152
Author(s):  
Guo Hua Wang ◽  
Niu Yi Sun ◽  
Juan Qin ◽  
Wei Min Shi ◽  
Lin Jun Wang
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Film Structure ◽  
Root Mean Square Roughness ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Diffraction Peaks ◽  
Xrd Patterns ◽  
Sputtering Pressure

Half-Heusler compound YNiBi thin films have been prepared by direct current (DC) magnetron sputtering from an YNiBi target. The film structure and surface morphology of YNiBi thin films were analyzed with X-ray diffraction (XRD) and atomic force microscopy (AFM). The electrical properties of the films were studied by Hall measurements. XRD patterns show that the films prepared at lower sputtering pressure and higher growth temperature exhibit minimum full width at half maximum (FWHM) and maximum diffraction peaks which belong to the same family of crystal planes. Results of AFM reveal that the surface of a variety of fabricated YNiBi films is smooth and keeps good adhesion to the substrate. The increasing of substrate temperature and slightly lowering of sputtering pressure are in favor of reducing the root mean square roughness during magnetron sputtering process. The film with high crystallinity has an electrical conductivity of 938 S/cm and carrier concentration of 2.15×1021cm-3.

scholarly journals The Effect of Annealing on The Structural and Optical Properties of Copper Oxide Thin Films Prepared by SILAR Method

2014 ◽  
Vol 11 (2) ◽  
pp. 718-729
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Copper Oxide ◽  
Annealed Sample ◽  
Film Structure ◽  
X Rays ◽  
Oxide Thin Films ◽  
Silar Method ◽  
Average Grain Size ◽  
Xrd Patterns

Copper oxide thin films were deposited on glass substrate using Successive Ionic Layer Adsorption and Reaction (SILAR) method at room temperature. The thickness of the thin films was around 0.43?m.Copper oxide thin films were annealed in air at (200, 300 and 400°C for 45min.The film structure properties were characterized by x-ray diffraction (XRD). XRD patterns indicated the presence of polycrystalline CuO. The average grain size is calculated from the X-rays pattern, it is found that the grain size increased with increasing annealing temperature. Optical transmitter microscope (OTM) and atomic force microscope (AFM) was also used. Direct band gap values of 2.2 eV for an annealed sample and (2, 1.5, 1.4) eV at 200, 300,400oC respectively.

The Precipitation of Si in AlCuSi Thin Films

1973 ◽  
Vol 31 ◽  
pp. 34-35 ◽  
Author(s):  
R. M. Anderson
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Heat Treatment ◽  
Solid Solution ◽  
Integrated Circuit ◽  
Copper Film ◽  
Solution Concentration ◽  
X Ray ◽  
Silicon Thin Films ◽  
Before And After

Aluminum-copper-silicon thin films have been considered as an interconnection metallurgy for integrated circuit applications. Various schemes have been proposed to incorporate small percent-ages of silicon into films that typically contain two to five percent copper. We undertook a study of the total effect of silicon on the aluminum copper film as revealed by transmission electron microscopy, scanning electron microscopy, x-ray diffraction and ion microprobe techniques as a function of the various deposition methods.X-ray investigations noted a change in solid solution concentration as a function of Si content before and after heat-treatment. The amount of solid solution in the Al increased with heat-treatment for films with ≥2% silicon and decreased for films <2% silicon.

Preferential Orientation of Photochromic Gadolinium Oxyhydrides

2020 ◽  
Author(s):  
Elbruz Murat Baba ◽  
Jose Montero ◽  
Dmitrii Moldarev ◽  
Marcos V. Moro ◽  
Max Wolff ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Rare Earth ◽  
Preferential Orientation ◽  
Reactive Magnetron ◽  
Flow Ratio ◽  
Deposition Pressure ◽  
Step Process ◽  
Oxidation In Air ◽  
Key Parameter

<p>We report preferential orientation control in photochromic gadolinium oxyhydride (GdHO) thin films deposited by a two-step process. Gadolinium hydride (GdH<sub>2-x</sub>) films were grown by reactive magnetron sputtering, followed by oxidation in air. The preferential orientation, grain size, anion concentrations, and photochromic response of the films are strongly dependent on the deposition pressure. GdHO films show preferential orientation along the [100] direction and exhibit photochromism when synthesized at deposition pressures up to 5.8 Pa and. The photochromic contrast is larger than 20 % when the films are deposited below 2.8 Pa with 0.22 H<sub>2</sub>/Ar flow ratio. We argue that the degree of preferential orientation defines the oxygen concentration which is known to be a key parameter for photochromism in rare-earth oxyhydride thin films. The experimental observations described above are explained by the oxidation-induced decrease of the grain size as a result of the increase of the deposition pressure of the sputtering gas. </p>

PYROMET 538

Alloy Digest ◽  
1970 ◽  
Vol 19 (12) ◽  
Keyword(s):  
Solid Solution ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
Heat Treating ◽  
Temperature Performance ◽  
Technology Corporation ◽  
Carpenter Technology Corporation

Abstract PYROMET 538 is a solid-solution strengthened, austenitic alloy with a desirable combination of strength, corrosion resistance, oxidation resistance, and economy. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-247. Producer or source: Carpenter Technology Corporation.

scholarly journals Ultra-high oxidation resistance of nano-structured thin films

2021 ◽  
Vol 201 ◽  
pp. 109499
Author(s):  
E. Aschauer ◽  
T. Wojcik ◽  
P. Polcik ◽  
O. Hunold ◽  
M. Arndt ◽  
...  
Keyword(s):  
Thin Films ◽  
Oxidation Resistance ◽  
High Oxidation ◽  
High Oxidation Resistance

scholarly journals Oxidation behavior of non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution powders in air

2021 ◽  
Author(s):  
Huilin Lun ◽  
Yi Zeng ◽  
Xiang Xiong ◽  
Ziming Ye ◽  
Zhongwei Zhang ◽  
...  
Keyword(s):  
Solid Solution ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Group Iv ◽  
Hypersonic Vehicles ◽  
Metal Carbides ◽  
Initial Oxidation ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Kinetics Of

AbstractMulti-component solid solutions with non-stoichiometric compositions are characteristics of ultra-high temperature carbides as promising materials for hypersonic vehicles. However, for group IV transition-metal carbides, the oxidation behavior of multi-component non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution has not been clarified yet. The present work fabricated four kinds of (Zr,Hf,Ti)Cx carbide solid solution powders by free-pressureless spark plasma sintering to investigate the oxidation behavior of (Zr,Hf,Ti)Cx in air. The effects of metallic atom composition on oxidation resistance were examined. The results indicate that the oxidation kinetics of (Zr,Hf,Ti)Cx are composition dependent. A high Hf content in (Zr,Hf,Ti)Cx was beneficial to form an amorphous Zr-Hf-Ti-C-O oxycarbide layer as an oxygen barrier to enhance the initial oxidation resistance. Meanwhile, an equiatomic ratio of metallic atoms reduced the growth rate of (Zr,Hf,Ti)O2 oxide, increasing its phase stability at high temperatures, which improved the oxidation activation energy of (Zr, Hf, Ti)Cx.

scholarly journals Effect of film structure on CH3NH3PbI3 perovskite thin films’ degradation

AIP Advances ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 025226
Author(s):  
F. Khelfaoui ◽  
I. Belaidi ◽  
N. Attaf ◽  
M. S. Aida
Keyword(s):  
Thin Films ◽  
Film Structure
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