scholarly journals Synthesis and Characterization of Complex Nanostructured Thin Films Based on Titanium for Industrial Applications

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 399 ◽  
Author(s):  
Rodica Vladoiu ◽  
Aurelia Mandes ◽  
Virginia Dinca ◽  
Maria Balasoiu ◽  
Dmytro Soloviov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Lattice Parameter ◽  
Industrial Applications ◽  
Vacuum Arc ◽  
Average Roughness ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Cubic System ◽  
Gear Wheels ◽  
Thermionic Vacuum Arc

Titanium-based composites—titanium and silver (TiAg) and titanium and carbon (TiC)—were synthesized by the Thermionic Vacuum Arc (TVA) method on substrates especially for gear wheels and camshaft coating as mechanical components of irrigation pumps. The films were characterized by surface morphology, microstructure, and roughness through X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Small-Angle Neutron Scattering (SANS). The silver (Ag) films crystallized into a cubic system with lattice a = 4.0833 Å at room temperature, indexed as cubic Ag group Fm3m. The crystallites were oriented in the [111] direction, and mean grain size was <D>111 = 265 Å. The TiC structure revealed a predominant cubic TiC phase, with a = 0.4098 as a lattice parameter determined by Cohen’s method. Average roughness (Ra) was 8 nm for the as-grown 170 nm thick TiAg film, and 1.8 nm for the as-grown 120 nm thick TiC film. Characteristic SANS contribution was detected from the TiAg layer deposited on a substrate of high-quality stainless steel with 0.45% carbon (OLC45) in the range of 0.015 Å−1 ≤ Q ≤ 0.4 Å−1, revealing the presence of sharp surfaces and an averaged triaxial ellipsoidal core-shell object.

scholarly journals Structural and Mechanical Properties of Nanostructured C-Ag Thin Films Synthesized by Thermionic Vacuum Arc Method

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Rodica Vladoiu ◽  
Aurelia Mandes ◽  
Virginia Dinca-Balan ◽  
Vilma Bursikova
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Mechanical Properties ◽  
Elastic Modulus ◽  
Silicon Substrate ◽  
Vacuum Arc ◽  
Average Roughness ◽  
Thermionic Vacuum Arc ◽  
Induced Aggregation ◽  
Ag Film

Nanostructured C-Ag thin films of 200 nm thickness were successfully synthesized by the Thermionic Vacuum Arc (TVA) method. The influence of different substrates (glass, silicon wafers, and stainless steel) on the microstructure, morphology, and mechanical properties of nanostructured C-Ag thin films was characterized by High-Resolution Transmission Electron Microscopy (HRTEM), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and TI 950 (Hysitron) nanoindenter equipped with Berkovich indenter, respectively. The film’s hardness deposited on glass (HC-Ag/Gl = 1.8 GPa) was slightly lower than in the case of the C-Ag film deposited on a silicon substrate (HC-Ag/Si = 2.2 GPa). Also the apparent elastic modulus Eeff was lower for C-Ag/Gl sample (Eeff = 100 GPa) than for C-Ag/Si (Eeff = 170 GPa), while the values for average roughness are Ra=2.9 nm (C-Ag/Si) and Ra=10.6 (C-Ag/Gl). Using the modulus mapping mode, spontaneous and indentation-induced aggregation of the silver nanoparticles was observed for both C-Ag/Gl and C-Ag/Si samples. The nanocomposite C-Ag film exhibited not only higher hardness and effective elastic modulus, but also a higher fracture resistance toughness to the silicon substrate compared to the glass substrate.

scholarly journals Polarized Catalytic Polymer Nanofibers

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2859 ◽  
Author(s):  
Dinesh Lolla ◽  
Ahmed Abutaleb ◽  
Marjan A. Kashfipour ◽  
George G. Chase
Keyword(s):  
Electron Microscopy ◽  
Metallic Nanoparticles ◽  
Polyvinylidene Fluoride ◽  
Morphological Changes ◽  
Industrial Applications ◽  
Metallic Nanoparticle ◽  
Cross Sectional ◽  
Force Microscopy ◽  
Catalytic Support ◽  
Transmission Electron

Molecular scale modifications were achieved by spontaneous polarization which is favored in enhancements of β-crystallization phase inside polyvinylidene fluoride (PVDF) nanofibers (NFs). These improvements were much more effective in nano and submicron fibers compared to fibers with relatively larger diameters. Metallic nanoparticles (NPs) supported by nanofibrous membranes opened new vistas in filtration, catalysis, and serving as most reliable resources in numerous other industrial applications. In this research, hydrogenation of phenol was studied as a model to test the effectiveness of polarized PVDF nanofiber support embedded with agglomerated palladium (Pd) metallic nanoparticle diameters ranging from 5–50 nm supported on polymeric PVDF NFs with ~200 nm in cross-sectional diameters. Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM), Energy Dispersive X-Ray Spectroscopy (EDX), Fourier Transform Infrared Spectroscopy (FTIR) and other analytical analysis revealed both molecular and surface morphological changes associated with polarization treatment. The results showed that the fibers mats heated to their curie temperature (150 °C) increased the catalytic activity and decreased the selectivity by yielding substantial amounts of undesired product (cyclohexanol) alongside with the desired product (cyclohexanone). Over 95% phenol conversion with excellent cyclohexanone selectivity was obtained less than nine hours of reaction using the polarized PVDF nanofibers as catalytic support structures.

scholarly journals Characterization of Platinum-Based Thin Films Deposited by Thermionic Vacuum Arc (TVA) Method

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1796
Author(s):  
Sebastian Cozma ◽  
Rodica Vlǎdoiu ◽  
Aurelia Mandes ◽  
Virginia Dinca ◽  
Gabriel Prodan ◽  
...  
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Materials Science ◽  
Vacuum Arc ◽  
Silicon Substrates ◽  
Force Microscopy ◽  
Energy Evaluation ◽  
Transmission Electron ◽  
Potential Applications ◽  
Thermionic Vacuum Arc

The current work aimed to characterize the morphology, chemical, and mechanical properties of Pt and PtTi thin films deposited via thermionic vacuum arc (TVA) method on glass and silicon substrates. The deposited thin films were characterized by means of a scanning electron microscope technique (SEM). The quantitative elemental microanalysis was done using energy-dispersive X-ray spectroscopy (EDS). The tribological properties were studied by a ball-on-disc tribometer, and the mechanical properties were measured using nanoindentation tests. The roughness, as well as the micro and nanoscale features, were characterized using atomic force microscopy (AFM) and transmission electron microscopy (TEM). The wettability of the deposited Pt and PtTi thin films was investigated by the surface free energy evaluation (SFE) method. The purpose of our study was to prove the potential applications of Pt-based thin films in fields, such as nanoelectronics, fuel cells, medicine, and materials science.

scholarly journals Morphology, microstructure and magnetic properties of thermionic vacuum arc deposited NiFeCu ferromagnetic thin films

2012 ◽  
Vol 23 (1) ◽  
pp. 21-26
Author(s):  
Viorel Ionescu ◽  
Gabriel Prodan ◽  
Ionut Jepu ◽  
Ion Mustata ◽  
Cristian Petrica Lungu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Morphological Properties ◽  
Vacuum Arc ◽  
Spectroscopy Analysis ◽  
Kerr Rotation ◽  
Ferromagnetic Thin Films ◽  
Transmission Electron ◽  
Thermionic Vacuum Arc ◽  
Microstructure And Magnetic Properties

AbstractNiFeCo granular ferromagnetic thin films were deposited on glass and silicon wafer substrates in thermionic vacuum arc plasma with simultaneous ignition of plasma in Cu and NiFe vapors. The structural and morphological properties of the prepared films were investigated by TEM Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). Elemental composition of the films was revealed after X-ray energy dispersive spectroscopy analysis (EDAX). The magneto-optical longitudinal Kerr rotation spectra of the samples were also measured and compared.

KINETICS, MICROSTRUCTURE AND STRAIN IN GaN THIN FILMS GROWN VIA PENDEO-EPITAXY

2004 ◽  
Vol 14 (01) ◽  
pp. 21-37
Author(s):  
A. M. ROSKOWSKI ◽  
E. A. PREBLE ◽  
S. EINFELDT ◽  
P. M. MIRAGLIA ◽  
J. SCHUCK ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Growth Conditions ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Force Microscopy ◽  
Microelectronic Devices ◽  
Atomic Force ◽  
Transmission Electron ◽  
Thermal Stability Of

Maskless pendeo-epitaxy involves the lateral and vertical growth of cantilevered "wings" of material from the sidewalls of unmasked etched forms. Gallium Nitride films grown at 1020°C via metalorganic vapor phase epitaxy on GaN / AlN /6 H - SiC (0001) substrates previously etched to form [Formula: see text]-oriented stripes exhibited similar vertical [0001] and lateral [Formula: see text] growth rates, as shown by cross-sectional scanning electron microscopy. Increasing the temperature increased the growth rate in the latter direction due to the higher thermal stability of the [Formula: see text] surface. The [Formula: see text] surface was atomically smooth under all growth conditions with a root mean square (RMS)=0.17 nm. High resolution X-ray diffraction and atomic force microscopy of the pendeo-epitaxial films confirmed transmission electron microscopy results regarding the significant reduction in dislocation density in the wings. This result is important for the properties of both optoelectronic and microelectronic devices fabricated in III-Nitride structures. Measurement of strain indicated that the wing material is crystallographically relaxed as evidenced by the increase in the c-axis lattice parameter and the upward shift of the E2 Raman line frequency. A strong D°X peak at 3.466 eV was also measured in the wing material. However, tilting of the wings of ≤0.15° occurred due to the tensile stresses in the stripes induced by the mismatch in the coefficients of thermal expansion between the GaN and the underlying substrate.

scholarly journals The Domain and Microstructure of Resin-Bonded Magnets

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2849
Author(s):  
Marcin Jan Dośpiał
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Size ◽  
Size Distribution ◽  
Domain Structure ◽  
Grain Size Distribution ◽  
Exchange Interactions ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Scanning Electron

This paper presents domain and structure studies of bonded magnets made from nanocrystalline Nd-(Fe, Co)-B powder. The structure studies were investigated using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Mössbauer spectroscopy and X-ray diffractometry. On the basis of performed qualitative and quantitative phase composition studies, it was found that investigated alloy was mainly composed of Nd2(Fe-Co)14B hard magnetic phase (98 vol%) and a small amount of Nd1.1Fe4B4 paramagnetic phase (2 vol%). The best fit of grain size distribution was achieved for the lognormal function. The mean grain size determined from transmission electron microscopy (TEM) images on the basis of grain size distribution and diffraction pattern using the Bragg equation was about ≈130 nm. HRTEM images showed that over-stoichiometric Nd was mainly distributed on the grain boundaries as a thin amorphous border of 2 nm in width. The domain structure was investigated using a scanning electron microscope and metallographic light microscope, respectively, by Bitter and Kerr methods, and by magnetic force microscopy. Domain structure studies revealed that the observed domain structure had a labyrinth shape, which is typically observed in magnets, where strong exchange interactions between grains are present. The analysis of the domain structure in different states of magnetization revealed the dynamics of the reversal magnetization process.

scholarly journals The Examination of Calcium ion Implanted Alumina with Energy Filtered Transmission Electron Microscopy

1997 ◽  
Vol 3 (S2) ◽  
pp. 413-414
Author(s):  
E.M. Hunt ◽  
J.M. Hampikian ◽  
N.D. Evans
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Pure Aluminum ◽  
Lattice Parameter ◽  
Face Centered Cubic ◽  
Ion Channeling ◽  
Transmission Electron ◽  
Knoop Microhardness ◽  
Aluminum Nanocrystals ◽  
Face Centered

Ion implantation can be used to alter the optical response of insulators through the formation of embedded nano-sized particles. Single crystal alumina has been implanted at ambient temperature with 50 keV Ca+ to a fluence of 5 x 1016 ions/cm2. Ion channeling, Knoop microhardness measurements, and transmission electron microscopy (TEM) indicate that the alumina surface layer was amorphized by the implant. TEM also revealed nano-sized crystals ≈7 - 8 nm in diameter as seen in Figure 1. These nanocrystals are randomly oriented, and exhibit a face-centered cubic structure (FCC) with a lattice parameter of 0.409 nm ± 0.002 nm. The similarity between this crystallography and that of pure aluminum (which is FCC with a lattice parameter of 0.404 nm) suggests that they are metallic aluminum nanocrystals with a slightly dilated lattice parameter, possibly due to the incorporation of a small amount of calcium.Energy-filtered transmission electron microscopy (EFTEM) provides an avenue by which to confirm the metallic nature of the aluminum involved in the nanocrystals.

Defect-Engineered Graded GexSi1-x Buffers on Si (001) with Extreme Low Threading Dislocation Density

1995 ◽  
Vol 378 ◽  
Author(s):  
G. Kissinger ◽  
T. Morgenstern ◽  
G. Morgenstern ◽  
H. B. Erzgräber ◽  
H. Richter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Dislocation Density ◽  
Threading Dislocation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Threading Dislocation Density

AbstractStepwise equilibrated graded GexSii-x (x≤0.2) buffers with threading dislocation densities between 102 and 103 cm−2 on the whole area of 4 inch silicon wafers were grown and studied by transmission electron microscopy, defect etching, atomic force microscopy and photoluminescence spectroscopy.

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