scholarly journals Influence of Laser-Assisted Fusing on Microstructural Evolution and Tribological Properties of NiWCrSiB Coating

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 548 ◽  
Author(s):  
Changkyoo Park ◽  
Eun-Joon Chun
Keyword(s):  
Spray Coating ◽  
Thermal Spray Coating ◽  
Temperature Control System ◽  
Secondary Phases ◽  
Hardening Behavior ◽  
Transmission Electron ◽  
Transmission Electron Microscope Analysis ◽  
Electron Microscope Analysis ◽  
Sprayed Coating ◽  
M23c6 Carbides

The present study examines the applicability of a diode laser-assisted fusing treatment and a temperature-control system to the NiWCrSiB thermal spray coating to develop the enhanced wear resistance of continuous-casting molds. As a result of the use of the lasers, the variations in the microstructure and the hardening behavior during the fusing treatment could be controlled. Fine secondary phases (approximately 0.05–10 μm in size) homogeneously present in the coating after the laser-assisted fusing were observed to be Cr-, Mo- and W-based carbides and borides. Transmission electron microscope analysis was used to characterize these fine secondary phases as M7C3 and M23C6 carbides and M5B3 boride. Because of these fine secondary phases, the hardness increased from 730 (as-sprayed status) to 1230 HV (after fusing at a temperature of 1473 K). Finally, given the formation of fine secondary phases and the occurrence of surface hardening, the laser-assisted fusing treatment was deemed to enhance the tribological performance of the thermal-sprayed coating, in that it exhibited a lower coefficient of friction and lower wear rate than the as-sprayed coating.

Effect of Calcinations on Characterizations of Fabricated Nano Manganese Ferrite

2013 ◽  
Vol 634-638 ◽  
pp. 2150-2154 ◽  
Author(s):  
Rita Sundari ◽  
Tang Ing Hua ◽  
M. Rusli Yosfiah
Keyword(s):  
Sol Gel ◽  
Volatile Components ◽  
Manganese Ferrite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Reflectance Analysis ◽  
Transmission Electron Microscope Analysis ◽  
Electron Microscope Analysis ◽  
Nano Size

A citric acid anionic surfactant has been applied for nano manganese ferrite (MnFeO3) fabrication using sol gel method. The calcinations have been varied for 300, 600 and 800oC. The UVDR (UV-Vis Diffused Reflectance) analysis shows a high absorptive band gap after 400 nm for the 600oC calcinated MnFeO3. The DTA (Differential Thermal Analysis) profiles exhibit remarkably trapped volatile matters (H2O, CO2, and NO2) in the fabricated MnFeO3 under sol gel heat treatment at 100oC and the peaks disappeared as the calcination increased to 600oC. As the temperature elevated from 100 to 300oC, the absorption peaks of volatile components are disappeared as demonstrated clearly by the FTIR (Fourier Transform Infrared) spectra of the fabricated material, which 3393 cm-1 corresponded to OH group, 1624 cm-1 to CO group, and 1384 cm-1 to NO group. The XRD (X-Ray Diffraction) spectra show clearly the alteration process from amorphous to crystalline structure as the calcinations increased from 300 to 600oC. In addition, the TEM (Transmission Electron Microscope) analysis exhibits parts of the fabricated MnFeO3 found in cubic nano size of 15-40 nm under interested calcinations and the result is in agreement with that obtained by XRD investigation.

Microstructure of Interfacial Basal Plane Dislocations in 4H-SiC Epilayers

2019 ◽  
Vol 954 ◽  
pp. 77-81
Author(s):  
Zhe Li ◽  
Xuan Zhang ◽  
Ze Hong Zhang ◽  
Li Guo Zhang ◽  
Tao Ju ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Cross Section ◽  
Basal Plane ◽  
Power Devices ◽  
Etch Pits ◽  
Transmission Electron ◽  
Interfacial Dislocations ◽  
Transmission Electron Microscope Analysis ◽  
Electron Microscope Analysis ◽  
Special Category

As SiC power devices are being developed toward ultrahigh-voltage bipolar structures, the density of basal plane dislocations in SiC epilayers has to be minimized. In this work, a special category of basal plane dislocations, i.e. interfacial dislocations, was investigated. Their etch pits were detected at the interface and the microstructure was revealed by cross-section transmission electron microscope analysis.

The Optical and Electrical Properties of SiOx(x<2) Thin Films Prepared by Pulsed Laser Deposition Technique

2007 ◽  
Vol 997 ◽  
Author(s):  
Byoung Youl Park ◽  
Sol Lee ◽  
Chang Hyun Bae ◽  
Seung Min Park ◽  
Kyoungwan Park
Keyword(s):  
Pulsed Laser Deposition ◽  
Crystalline Silicon ◽  
Quantum Confinement Effect ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
X Ray ◽  
Post Annealing ◽  
Transmission Electron ◽  
Transmission Electron Microscope Analysis ◽  
Electron Microscope Analysis

AbstractSiOx (x<2) films were deposited in an O2 atmosphere using Si target in a pulsed laser deposition system. Post-annealing process was employed in an O2 atmosphere to form the nanometer-sized Si crystallites embedded in the SiO2 films. The transmission electron microscope analysis shows the existence of crystalline silicon nano-dots with diameters ranging from 2 to 4 nm. Also, the clear separation of Si and SiO2 phases can be seen in the X-ray photoemission spectra. Photoluminescence peak from the annealed films was obtained, which is attributed to the quantum confinement effect of the Si nano-dots. C-V measurements of the metal-oxide-silicon (MOS) structure containing the silicon nano-dots in the oxide layer were performed to investigate the charging/discharging behavior of the silicon nano-dots. The maximum program window of the MOS was measured to be4.1V under ±5V sweep.

scholarly journals Significant differences in nucleocapsid morphology within the Paramyxoviridae

2002 ◽  
Vol 83 (8) ◽  
pp. 1831-1839 ◽  
Author(s):  
David Bhella ◽  
Adam Ralph ◽  
Lindsay B. Murphy ◽  
Robert P. Yeo
Keyword(s):  
Measles Virus ◽  
Sendai Virus ◽  
Simian Virus ◽  
N Protein ◽  
Transmission Electron ◽  
Ring Structures ◽  
Transmission Electron Microscope Analysis ◽  
Electron Microscope Analysis ◽  
Syncytial Virus ◽  
Multiple Conformations

Nucleocapsid (N) proteins from representative viruses of three genera within the Paramyxoviridae were expressed in insect cells using recombinant baculoviruses. RNA-containing structures, which appear morphologically identical to viral nucleocapsids, were isolated and subsequently imaged under a transmission electron microscope. Analysis of these images revealed marked differences in nucleocapsid morphology among the genera investigated, most notably between viruses of the Paramyxovirinae and the Pneumovirinae subfamilies. Helical pitch measurements were made, revealing that measles virus (MV, a Morbillivirus within the subfamily Paramyxovirinae) N protein produces helices that adopt multiple conformations with varying degrees of flexibility, while that of the Rubulavirus simian virus type 5 (SV5, subfamily Paramyxovirinae) produces more rigid structures with a less heterogeneous pitch distribution. Nucleocapsids produced by respiratory syncytial virus (RSV, subfamily Pneumovirinae) appear significantly narrower than those of MV and SV5 and have a longer pitch than the most extended form of MV. In addition to helical nucleocapsids, ring structures were also produced, image analysis of which has demonstrated that rings assembled from MV N protein consist of 13 subunits. This is consistent with previous reports that Sendai virus nucleocapsids have 13·07 subunits per turn. It was determined, however, that SV5 subnucleocapsid rings have 14 subunits, while rings derived from the radically different RSV nucleocapsid have been found to contain predominantly 10 subunits.

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