Process Study on Prepared Al2O3-TiB2 Composite Coating by Reactive Spray

2012 ◽  
Vol 472-475 ◽  
pp. 309-312
Author(s):  
Xiao Ping Zhou ◽  
Ming Li ◽  
Xin Zhou

The microstructures and properties of Al2O3-TiB2 composite coating on the surface of the aluminum alloy by reactive spraying was studied. The influences of mechanical alloying and spraying temperature on the phase constituent and microstructure of the composite were analyzed by X-ray diffractometry(XRD) and scanning electron microscopy(SEM). The results indicate that Al2O3-TiB2 composite coating is obtained by plasma spraying using milled powder of Al,TiO2,B2O and B2O3. The coating possesses high microhardness of 1300 HV0.1.

Author(s):  
Bo Xu ◽  
Yafeng He ◽  
Xiangzhi Wang ◽  
Weimin Gan

Abstract Ceramic coatings were prepared on the surface of 7050 highstrength aluminum alloy using micro-arc oxidation in an aluminate electrolyte with added graphene. To analyze the surface morphology, roughness, phase composition, and corrosion resistance, scanning electron microscopy, X-ray diffraction, X-ray photoelectron, and electrochemical measurements were used, respectively. The addition of 9 g · L-1 of graphene to the electrolyte decreased the micro-pore size of the composite coatings and improved the density. In addition, with the addition of graphene, the roughness was the lowest, and the corrosion resistance was significantly improved.


2011 ◽  
Vol 204-210 ◽  
pp. 1741-1744
Author(s):  
Li Jie Wang ◽  
Jun Sheng Yang ◽  
Bo Sun ◽  
Xiao Dong Tian

A composite coating was prepared on Ti-6Al-4V surface by the combination of nitriding, Mo-sputtering and sulfurizing treatments. The microstructure and phase constituent of the composite coating were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Furthermore, the cross-sectional hardness gradient of the coating was determined. The results revealed that the composite coating consisted of Ti, Mo, MoS2, TiN and transition layer and the grain size of the sulfides formed on the coating surface were different with treatment temperature. The examination of the cross-sectional hardness of the composite coating revealed that the coating was an ideal tribological surface.


2014 ◽  
Vol 798-799 ◽  
pp. 154-159 ◽  
Author(s):  
José Carlos da Silva Oliveira ◽  
Ricardo Arthur Sanguinetti Ferreira ◽  
Yogendra Prasad Yadava

This work has as main objectives to produce the ceramic Sr2MgWO6and evaluate their reactivity to petroleum. Powders of SrCO3, MgO and WO3were selected, taken in stoichiometric amounts and synthesized by conventional route. The synthesis was characterized by size distribution, specific surface area and thermogravimetric analysis (TGA). The synthesis was also fragmented into ball mill and characterized by specific surface. It was compacted, then was calcined at 1200 °C and analyzed by X-ray diffraction. The powders Sr2MgWO6with perovskite structure were compacted and sintered at 1250, 1300 and 1350 °C. The materials produced were evaluated by microhardness, scanning electron microscopy (SEM), diffraction of X-rays and tests submersion in petroleum. The results showed that the ceramics have high microhardness and potential to be used in chemically aggressive environments such as petroleum.


2020 ◽  
Vol 987 ◽  
pp. 53-58 ◽  
Author(s):  
Marina G. Kovaleva ◽  
Igor Yu. Goncharov ◽  
Vseslav Yu. Novikov ◽  
Ivan A. Pavlenko ◽  
Maxim N. Yapryntsev ◽  
...  

A new multi-chamber detonation accelerator (MCDS) was applied to fabricate ZrB2–MoSi2 composite coating containing 20 mol.% of MoSi2 on carbon/carbon composites. Phase composition and microstructure of the coating were characterized by X-ray diffraction and scanning electron microscopy. The ZrB2–20MoSi2 coating displayed compact and lamellar microstructure with porosity lower than 1%, where SiO2 phase was uniformly distributed in the ZrO2 matrix. The coating was well-adhered with carbon/carbon composites. Silica, m-ZrO2, and small amount of Zr(MoO4)2 were formed.


2010 ◽  
Vol 154-155 ◽  
pp. 727-730 ◽  
Author(s):  
Li Jie Wang ◽  
Xiao Dong Tian ◽  
Jun Sheng Yang

The MoS2/TiN composite coating was prepared on Ti-6Al-4V by the combination of plasma diffusion and magnetron sputtering techniques. The microstructure and phase constituents of the composite coating were analyzed by scanning electron microscopy(SEM) and X-ray diffraction(XRD). The abrasion resistance of the composite coating was examined on MM-200 abrasion tester. The results revealed that the composite coating consisted of MoS2, Mo, TiN and Ti phases, and its abrasion resistance was excellent under dry friction and absolute sliding.


2010 ◽  
Vol 97-101 ◽  
pp. 1558-1561 ◽  
Author(s):  
Li Jie Wang ◽  
Ya Zhe Xing ◽  
Hong Bo Wang ◽  
Jian Min Hao

Three composite coatings were prepared by nitriding-sulfurizing processing of Ti-6Al-4V alloy at different sulfurizing temperatures. The microstructure and phase structure of the coatings were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Furthermore, the hardness of the coatings was measured. The effect of the sulfurizing temperature on microstructure of coatings was investigated. The results indicated that the composite coating was mainly comprised of titanium nitrides, titanium sulfides, and titanium. It was found that the phase composition of composite coating changed with the variation of the sulfurizing temperature.


Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.


Author(s):  
M. L. Zimny ◽  
A. C. Haller

During hibernation the ground squirrel is immobile, body temperature reduced and metabolism depressed. Hibernation has been shown to affect dental tissues varying degrees, although not much work has been done in this area. In limited studies, it has been shown that hibernation results in (1) mobilization of bone minerals; (2) deficient dentinogenesis and degeneration of alveolar bone; (3) presence of calculus and tears in the cementum; and (4) aggrevation of caries and pulpal and apical tooth abscesses. The purpose of this investigation was to study the effects of hibernation on dental tissues employing scanning electron microscopy (SEM) and related x-ray analyses.


Author(s):  
Yun Lu ◽  
David C. Joy

High resolution scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDXA) were performed to investigate microparticles in blended cements and their hydration products containing sodium-rich chemical wastes. The physical appearance of powder particles and the morphological development at different hydration stages were characterized by using high resolution SEM Hitachi S-900 and by SEM S-800 with a EDX spectrometer. Microparticles were dispersed on the sample holder and glued by 1% palomino solution. Hydrated bulk samples were dehydrated by acetone and mounted on the holder by silver paste. Both fracture surfaces and flat cutting sections of hydrating samples were prepared and examined. Some specimens were coated with an 3 nm thick Au-Pd or Cr layer to provide good conducting surfaces. For high resolution SEM S-900 observations the accelerating voltage of electrons was 1-2 KeV to protect the electron charging. Microchemical analyses were carried out by S800/EDS equipped with a LINK detector of take-off angle =40°.


Author(s):  
M.G. Baldini ◽  
S. Morinaga ◽  
D. Minasian ◽  
R. Feder ◽  
D. Sayre ◽  
...  

Contact X-ray imaging is presently developing as an important imaging technique in cell biology. Our recent studies on human platelets have demonstrated that the cytoskeleton of these cells contains photondense structures which can preferentially be imaged by soft X-ray imaging. Our present research has dealt with platelet activation, i.e., the complex phenomena which precede platelet appregation and are associated with profound changes in platelet cytoskeleton. Human platelets suspended in plasma were used. Whole cell mounts were fixed and dehydrated, then exposed to a stationary source of soft X-rays as previously described. Developed replicas and respective grids were studied by scanning electron microscopy (SEM).


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