scholarly journals Comparative Study of DC and RF Sputtered MoSe2 Coatings Containing Carbon—An Approach to Optimize Stoichiometry, Microstructure, Crystallinity and Hardness

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 133 ◽  
Author(s):  
Talha Bin Yaqub ◽  
Todor Vuchkov ◽  
Pedro Sanguino ◽  
Tomas Polcar ◽  
Albano Cavaleiro
Keyword(s):  
Electron Microscopy ◽  
Magnetron Sputtering ◽  
Solid Lubricant ◽  
Transition Metal Dichalcogenides ◽  
Low Carbon ◽  
X Ray Diffraction ◽  
Wavelength Dispersive Spectroscopy ◽  
Transmission Electron ◽  
Metal Dichalcogenides ◽  
Carbon Additions

Low stoichiometry, low crystallinity, low hardness and incongruencies involving the reported microstructure have limited the applicability of TMD-C (Transition metal dichalcogenides with carbon) solid-lubricant coatings. In this work, optimized Mo–Se–C coatings were deposited using confocal plasma magnetron sputtering to overcome the above-mentioned issues. Two different approaches were used; MoSe2 target powered by DC (direct current) or RF (radio frequency) magnetron sputtering. Carbon was always added by DC magnetron sputtering. Wavelength dispersive spectroscopy displayed Se/Mo stoichiometry of ~2, values higher than the literature. The Se/Mo ratio for RF-deposited coatings was lower than for their DC counterparts. Scanning electron microscopy showed that irrespective of the low carbon additions, the Mo–Se–C coatings were highly compact with no vestiges of columnar growth due to optimal bombardment of sputtered species. Application of substrate bias further improved compactness at the expense of lower Se/Mo ratio. X-ray diffraction, transmission electron microscopy, and Raman spectroscopy confirmed the presence of MoSe2 crystals, and (002) basal planes. Even very low carbon additions led to an improvement of the hardness of the coatings. The work reports a comparison between RF and DC sputtering of MoSe2 coatings with carbon and provides a guideline to optimize the composition, morphology, structure, and mechanical properties.

Variation of the Reversed Austenite Amount with the Tempering Temperature in a Fe-13%Cr-4%Ni-Mo Martensitic Stainless Steel

2010 ◽  
Vol 650 ◽  
pp. 193-198 ◽  
Author(s):  
Yuan Yuan Song ◽  
Xiu Yan Li ◽  
Fu Xing Yin ◽  
De Hai Ping ◽  
Li Jian Rong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stainless Steel ◽  
Martensitic Stainless Steel ◽  
Low Carbon ◽  
Reversed Austenite ◽  
X Ray Diffraction ◽  
Tempering Temperature ◽  
X Ray ◽  
Transmission Electron

Tempering temperature dependence of the amount of the reversed austenite in the range of 570 oC to 680 oC was investigated by means of X-ray diffraction (XRD) measurements and transmission electron microscopy (TEM) in a low carbon Fe-13%Cr-4%Ni-Mo (wt.%) martensitic stainless steel. It was found that the reversed austenite began to form at the tempered temperature slightly above the As temperature. As the tempered temperature increased, the amount of the reversed austenite changed little in the temperature range of 580-595 oC. Then, the amount of the reversed austenite increased sharply with the increased tempered temperature. When the tempered temperature increased to about 620 oC, the amount of the reversed austenite exhibited a peak. Afterward, it decreased quickly at the elevated tempered temperature. The microstructural evolvement of the reversed austenite at different tempering temperature was also observed by TEM.

scholarly journals Atomic structure of defects and dopants in 2D layered transition metal dichalcogenides

2018 ◽  
Vol 47 (17) ◽  
pp. 6764-6794 ◽  
Author(s):  
Shanshan Wang ◽  
Alex Robertson ◽  
Jamie H. Warner
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Transition Metal ◽  
Atomic Structure ◽  
Transition Metal Dichalcogenides ◽  
Transmission Electron ◽  
Metal Dichalcogenides ◽  
Layered Transition Metal

Transmission electron microscopy can directly image the detailed atomic structure of layered transition metal dichalcogenides, revealing defects and dopants.

scholarly journals Synthesis of Transition Metal Dichalcogenides based hybrid nanostructures by thermal decomposition method

2021 ◽  
Vol 2070 (1) ◽  
pp. 012095
Author(s):  
Melbin Baby ◽  
K. Rajeev Kumar
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Decomposition Method ◽  
Transition Metal Dichalcogenides ◽  
Hybrid Nanostructures ◽  
Hybrid Nanostructure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Decomposition Method ◽  
Metal Dichalcogenides

Abstract In this work, we report synthesis of hybrid nanostructures of Transition Metal Dichalcogenides via thermal decomposition method. Ammonium tetrathiomolybdate was used as not only growth templates but also as starting precursor for synthesis of hybrid nanostructures. The conditions for the synthesizing method were optimized using electron microscopy and x-ray diffraction. In this hybrid nanostructure synthesis, it was found that MoO3 nanorods are interspersed on exfoliated MoS2 nanosheets. The structural and optical properties of the hybrid nanostructure were investigated using transmission electron microscopy (TEM), Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and Ultraviolet Visible spectrophotometry (UV-VIS). The hybrid nanostructure of MoO3 on MoS2 shows a band gap of 2.2 eV. It was also found that by tuning the preparation parameters viz temperature of heating and time of heating, the composition of the hybrid nanostructure can be varied.

scholarly journals Microstructure and Oxidation Behavior of Metal V Films Deposited by Magnetron Sputtering

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 425 ◽  
Author(s):  
Song Zhang ◽  
Tingting Wang ◽  
Ziyu Zhang ◽  
Jun Li ◽  
Rong Tu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Surface Morphology ◽  
Magnetron Sputtering ◽  
Photoelectron Spectroscopy ◽  
Oxidation Behavior ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Force ◽  
Transmission Electron ◽  
Influence Of Substrate

Direct-current magnetron sputtering (DCMS) was applied to prepare vanadium (V) films on Si substrate. The influence of substrate temperature (Ts) and target–substrate distance (Dt–s) on phase structure and surface morphology of V films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscope (AFM) and transmission electron microscopy (TEM). The results show that the crystallinity of the V films increases with increasing Ts and decreasing Dt–s. The film deposited at Ts = 400 °C and Dt–s = 60 mm exhibits the best crystallinity and <111> preferred orientation with a regular tetrahedral surface morphology. Oxidation behavior of the V thin films has also been studied by X-ray photoelectron spectroscopy (XPS).

scholarly journals Structural and Mechanical Properties of CrNxCoatings Deposited by Medium-Frequency Magnetron Sputtering with and without Ion Source Assistance

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Can Xin Tian ◽  
Bing Yang ◽  
Jun He ◽  
Hong Jun Wang ◽  
De Jun Fu
Keyword(s):  
Electron Microscopy ◽  
Magnetron Sputtering ◽  
Ion Source ◽  
X Ray Diffraction ◽  
Medium Frequency ◽  
Force Microscopy ◽  
Mechanical And Tribological Properties ◽  
Atomic Force ◽  
Transmission Electron ◽  
Pin On Disc

CrNxcoatings were deposited on Si (100) and WC-Co substrates by a home-made medium-frequency magnetron sputtering system with and without thermal filament ion source assistance. The structure and composition of the coatings were characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy, and transmission electron microscopy. The mechanical and tribological properties were assessed by microhardness and pin-on-disc testing. The ion source-assisted system showed a deposition rate of 3.88 μm/h, much higher than the value 2.2 μm/h without ion source assistance. The CrNxcoatings prepared with ion source assistance exhibited an increase in microhardness (up to 16.3 GPa) and adecrease in friction coefficient (down to 0.48) at the optimized cathode source-to-substrate distance.

Influence of Ammoniating Temperatures on Microstructures, Morphologies and Optical Properties of GaN/Nb Nanostructures by RF Magnetron Sputtering Technique

2012 ◽  
Vol 1439 ◽  
pp. 17-23
Author(s):  
Feng Shi ◽  
Chengshan Xue
Keyword(s):  
Electron Microscopy ◽  
Optical Properties ◽  
Magnetron Sputtering ◽  
Photoelectron Spectroscopy ◽  
Hexagonal Wurtzite Structure ◽  
Rf Magnetron Sputtering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gan Nanowires ◽  
Transmission Electron

AbstractGaN nanowires and nanorods have been successfully synthesized on Si (111) substrates by magnetron sputtering through ammoniating Ga2O3/Nb thin films and the effects of ammoniation temperatures on growth of GaN nanowires and nanorods were analyzed in detail. X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, and photoluminescence spectra were carried out to characterize microstructures, morphologies, and optical properties of GaN samples. The results demonstrate that sample after ammoniation at 950 °C is single crystal GaN with hexagonal wurtzite structure and high crystalline quality, having the size of 30 - 80 nm in diameter. After ammoniation at 1000 °C, GaN nanorods appear with smooth and clean surface and more than 100 nm in diameter. The optical properties of GaN nanowires grown at 950 °C and nanorods grown at 1000 °C are best with strong emission intensities.

Growth and Characterization of Well-Aligned RuO2/R-TiO2 Heteronanostructures on Sapphire (100) Substrates by Reactive Magnetron Sputtering

2011 ◽  
Vol 170 ◽  
pp. 78-82
Author(s):  
Hung Pin Hsu ◽  
Ying Sheng Huang ◽  
Chien Nan Yeh ◽  
Yi Min Chen ◽  
Dah Shyang Tsai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Magnetron Sputtering ◽  
Reactive Magnetron Sputtering ◽  
Reactive Magnetron ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Vertically Aligned ◽  
Xrd Patterns ◽  
Electron Diffractometry

We report the growth of well-aligned RuO2/R-TiO2 heteronanostructures on sapphire (100) substrates by reactive magnetron sputtering using Ti and Ru metal targets under different conditions. The surface morphology and structural properties of the as-deposited heteronanostructures were characterized using field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and selected-area electron diffractometry (SAED). The FESEM micrographs and XRD patterns indicated the growth of vertically aligned RuO2(001) nanotubes and twinned V-shaped RuO2(101) nanowedges (NWs) on top of R-TiO2 nanorods under different sputtering pressures. TEM and SAED characterizations of the V-shaped RuO2 NWs showed that the NWs are crystalline RuO2 with twin planes of (101) and twin direction of [ 01] at the V-junction.

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