Thermochromic Properties of Vanadium Oxide Films Prepared by R-HIPIMS Using Closed-Loop Controlled with Plasma Emission Monitoring

2018 ◽  
Vol 940 ◽  
pp. 114-119
Author(s):  
Chien Jen Tang ◽  
Wei Hsuan Hsu ◽  
Ching Tang Li
Keyword(s):  
Vanadium Dioxide ◽  
Emission Intensity ◽  
Pid Controller ◽  
Plasma Emission ◽  
X Ray Diffraction ◽  
X Ray ◽  
Emission Monitoring ◽  
Thermochromic Properties ◽  
Electrical Source ◽  
Plasma Emission Intensity

The vanadium dioxide films were deposited by reactive high-power impulse magnetron sputtering for different plasma emission intensity at the substrate temperature of 310 °C. The setpoint of plasma emission intensity was controlled by a PID controller with plasma-emission-monitoring. The vanadium dioxide films characteristics were measured by optical spectrophotometer, X-ray diffraction and electrical source meter.

New route for modification of thermochromic properties of vanadium dioxide films via high-energy X-ray irradiation

2019 ◽  
Vol 45 (2) ◽  
pp. 1661-1669 ◽  
Author(s):  
Maodong Zhu ◽  
Hu Wang ◽  
Bin Wang ◽  
Hongji Qi ◽  
Dongping Zhang ◽  
...  
Keyword(s):  
Vanadium Dioxide ◽  
High Energy ◽  
X Ray ◽  
Thermochromic Properties

Ash Deposition in a Wood-Fired Gas Turbine

1995 ◽  
Vol 117 (3) ◽  
pp. 509-512 ◽  
Author(s):  
K. W. Ragland ◽  
M. K. Misra ◽  
D. J. Aerts ◽  
C. A. Palmer
Keyword(s):  
Gas Turbine ◽  
Emission Spectroscopy ◽  
Plasma Emission ◽  
Ash Deposition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gravel Bed ◽  
Plasma Emission Spectroscopy

A small four-stage gas turbine was directly fired with woodchips using a novel downdraft, gravel-bed combustor for a total 250 hours of tests. The average turbine blockage due to deposits was 0.19 percent per hour. The composition of deposits was studied using plasma emission spectroscopy and x-ray diffraction. The main constituents of the deposits were CaO, MgO, and K2SO4. The deposits contained 5 to 15 percent potassium and 0.5 to 3 percent sulfur.

scholarly journals Effect of Cr Atom Plasma Emission Intensity on the Characteristics of Cr-DLC Films Deposited by Pulsed-DC Magnetron Sputtering

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 608
Author(s):  
Guang Li ◽  
Yi Xu ◽  
Yuan Xia
Keyword(s):  
Magnetron Sputtering ◽  
Emission Intensity ◽  
Gas Flow ◽  
Optical Emission ◽  
Scratch Test ◽  
Deposition Process ◽  
Plasma Emission ◽  
Cross Sectional ◽  
Pulsed Dc ◽  
Plasma Emission Intensity

A pulsed-dc (direct current) magnetron sputtering with a plasma emission monitor (PEM) system was applied to synthesize Cr-containing hydrogenated amorphous diamond-like carbon (Cr-DLC) films using a large-size industrial Cr target. The plasma emission intensity of a Cr atom at 358 nm wavelength was characterized by optical emission spectrometer (OES). C2H2 gas flow rate was precisely adjusted to obtain a stable plasma emission intensity. The relationships between Cr atom plasma emission intensity and the element concentration, cross-sectional morphology, deposition rate, microstructure, mechanical properties, and tribological properties of Cr-DLC films were investigated. Scanning electron microscope and Raman spectra were employed to analyze the chemical composition and microstructure, respectively. The mechanical and tribological behaviors were characterized and analyzed by using the nano-indentation, scratch test instrument, and ball-on-disk reciprocating friction/wear tester. The results indicate that the PEM system was successfully used in magnetron sputtering for a more stable Cr-DLC deposition process.

Preparation of Tungsten-Doped VO2 (M) Nanoparticles through Sol-Gel Method and Hydrothermal Synthesis

2014 ◽  
Vol 881-883 ◽  
pp. 960-963 ◽  
Author(s):  
Ji Qi ◽  
Bin Zhao ◽  
Naisen Yu ◽  
Chen Niu ◽  
Guan Gran Sun
Keyword(s):  
Phase Transition ◽  
Vanadium Dioxide ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
New Process ◽  
Scanning Electron

A new process was developed for synthesizing tungsten-doped vanadium dioxide VO2(M) from ammonium metavanadate. The process includes obtaining V2O5by pyrolysing NH4VO3, doping tungsten in V2O5by sol-gel method, and reducing V2O5to VO2(M) with hydrazine by hydrothermal method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) were applied to characterizing the product. The experimental results indicated that tungsten doped VO2(M) nanoparticles were successfully synthesized. The product VO2(M) presents mainly rod-like and block-like morphology. The phase transition temperature decreases with tungsten doped amount increasing, the phase transition takes place over the range from 36.23°C to 62.16°C and the largest enthalpy of the phase transition is 16.24J/g.

Effect of Compositions, Crystal Structures and Morphologies on Photo-Luminescent Property of LaPO4:Gd3+

2016 ◽  
Vol 848 ◽  
pp. 413-418 ◽  
Author(s):  
Luo Zhang ◽  
Xiao Yan Wang ◽  
Xin Wang ◽  
Hong Tao Ni
Keyword(s):  
Crystal Structures ◽  
Emission Intensity ◽  
Photo Luminescence ◽  
Atom Fraction ◽  
X Ray Diffraction ◽  
Mass Percentage ◽  
Higher Symmetry ◽  
X Ray ◽  
Maximum Value ◽  
Percentage Concentration

Various LaPO4:Gd3+ samples were synthesized by the hydrothermal method under different conditions to investigate the influence of crystalline structures, compositions and morphologies on the photo-luminescence. The compositions, crystal structures and morphologies were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and photo-luminescence emission spectrum (PL). The results revealed that the emission intensity of LaPO4:Gd3+ reached the maximum value as the mass percentage concentration of Gd3+ ions ascended to 3%. Monoclinic LaPO4:Gd3+ had stronger emission intensity than hexagonal sample which had more zeolitic water, higher symmetry and lower crystallinity. The nanospheres which dispersed better and had higher uniformity and surface atom fraction had the stronger PL intensity than the nanorods. It has been found that the La0.97Gd0.03PO4, which was prepared under the condition of pH=1, T=20 °C and excess PO43-, performed the best PL property after heat treatment at 900 °C for 4h.

An X-ray diffraction study of semiconductor and metallic vanadium dioxide

1993 ◽  
Vol 8 (4) ◽  
pp. 240-244 ◽  
Author(s):  
K. D. Rogers
Keyword(s):  
Vanadium Dioxide ◽  
Room Temperature ◽  
Transition Process ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Coexistence Of Phases ◽  
Diffraction Patterns ◽  
Tetragonal Cell ◽  
Monoclinic Cell

Powder diffraction data for semiconductor and metallic states of vanadium dioxide are presented. The structures are refined by Rietveld methods using a monoclinic cell (a = 5.7529Å, b = 4.5263Å, c = 5.3825Å, β = 122.61°) and space group P21/c for the room temperature data, and a tetragonal cell (a =4.5540Å, c = 2.8557Å) and space group P42/mnm for data collected at 400 K. The similarity between the corresponding X-ray diffraction patterns is discussed. The transition process from the monoclinic to tetragonal phase is investigated and initial evidence for the coexistence of phases over a small temperature range is presented.

scholarly journals Synthesis & characterization of nanostructure VO2 thin film

2021 ◽  
Vol 2070 (1) ◽  
pp. 012098
Author(s):  
P K Ojha ◽  
S K Mishra
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Vanadium Dioxide ◽  
Sol Gel ◽  
Cost Effective ◽  
Metallic Phase ◽  
Strongly Correlated ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Process

Abstract Vanadium dioxides are strongly correlated systems which undergo an insulator-metal transition (IMT) from a low-temperature semiconducting phase to a high-temperature metallic phase. Among them, Vanadium dioxide (VO2) undergoes IMT close to room temperature, accompanied by a structural transition resulting change of several orders of magnitude in the electrical and optical properties. Here, we present the synthesis of VO2 by sol-gel process which employs cost-effective precursors to synthesize pure phase of VO2 thin films. The synthesized thin films were characterized using an X-ray diffraction (XRD) to confirm phase purity and high resolution scanning electron microscope (HR-SEM) to study the crystallite and particle size for the synthesized films. The film’s surface was analyzed by X-ray photoelectron spectroscopy (XPS) to determine the valence state and chemical composition of vanadium dioxide.

scholarly journals Effects of annealing parameters on phase, structure and thermochromic properties of VO2 (M) derived from nanostructured VO2(B)

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hamdi Muhyuddin Barra ◽  
Soo Kien Chen ◽  
Nizam Tamchek ◽  
Zainal Abidin Talib ◽  
Oon Jew Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
X Ray ◽  
Thermogravimetric Analyzer ◽  
Different Temperatures ◽  
Thermochromic Properties ◽  
Scanning Electron

Abstract Synthesis of thermochromic VO2 (M) was successfully done by annealing hydrothermally-prepared VO2 (B) at different temperatures and times. Conversion of the metastable VO2 (B) to the thermochromic VO2 polymorph was studied using thermogravimetric analyzer (TGA) under N2 atmosphere. Moreover, the phase and morphology of the synthesized samples were studied using X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM), respectively. Accordingly, the XRD scans of all the annealed samples exhibited the presence of monoclinic VO2 (M), while the FE-SEM images of the samples showed the formation of nanorods and nanospheres, particularly those heated at high temperatures (650 °C and 700 °C). Meanwhile, differential scanning calorimetry (DSC) was used to measure the phase transition temperature (τc), hysteresis, and enthalpy of the prepared VO2. Based on these results, all samples displayed a τc of about 66 °C. However, the hysteresis was high for the samples annealed at lower temperatures (550 °C and 600 °C), while the enthalpy was very low for samples heated at lower annealing time (1.5 h and 1 h). These findings showed that crystallinity and nanostructure formation affected the thermochromic properties of the samples. In particular, the sample annealed at 650 °C showed better crystallinity and improved thermochromic behavior.

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