Non-Equilibrium Formation Of Silicon Nitride During Both Ball Milling And Ion Bombardment

1997 ◽  
Vol 481 ◽  
Author(s):  
Z. L. Li ◽  
J. S. Williams ◽  
D. J. Llewellyn ◽  
J. Wong-Leung ◽  
M. Giersig ◽  
...  

ABSTRACTPhase evolution during ball milling of Si in NH3 gas and during subsequent annealing has been studied and compared with nitride formation during ion bombardment of Si. X-ray diffraction, differential thermal analysis, Rutherford backscattering and channeling, combustion analysis and transmission electron microscopy have been used as analytical techniques. Results have shown that an amorphous SixNy(Fe) phase forms during milling which transforms into α-Si3N4 and FeSi2 on annealing. During ion bombardment, slightly N-rich Si3N4 is formed but it is mostly crystalline at temperatures between 150 and 450°C.

1997 ◽  
Vol 481 ◽  
Author(s):  
J. I Nikolov ◽  
J. S. Williams ◽  
D. J. Llewellyn ◽  
A. Calka

ABSTRACTPhase evolution during ball milling of Al in both N2 and NH3 gas has been compared and the annealing behaviour studied in some detail. X-ray diffraction, differential thermal analysis, combustion analysis and scanning and transmission electron microscopy have been used as analytical techniques. Results have shown that a nitride is not formed in N2 but that Al forms into many small, hollow spheres during milling. In contrast, milling in NH3 results in an amorphous AlxNy(O) phase which transforms into crystalline AIN and A12O3 on annealing to 1000°C.


2007 ◽  
Vol 353-358 ◽  
pp. 1505-1508
Author(s):  
Zhi Hua Yang ◽  
Yu Zhou ◽  
De Chang Jia ◽  
Qing Chang Meng ◽  
Chang Qing Yu

Amorphous Si-B-C-N ceramics obtained by high energy ball milling and hot pressing using hexagonal boron nitride (h-BN), graphite (C) and amorphous Si as starting materials have been studied. The mechanical milling with high energy resulted in the generation of large amounts of amorphous composites only milled for 5 h. Si-B-C-N powders were consolidation by hot pressing at 1850 °C. X-ray diffraction (XRD) and transmission electron microscopy (TEM) show that small amount of BN and SiC crystal lies in the amorphous matrix. The flexural strength reached the maximal value of 137.2 MPa at a mole ratio of BN/(Si+C) being 0.6.


Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Ruei-Cheng Lin ◽  
Tai-Kuang Lee ◽  
Der-Ho Wu ◽  
Ying-Chieh Lee

Ni-Cr-Si-Al-Ta resistive thin films were prepared on glass and Al2O3substrates by DC magnetron cosputtering from targets of Ni0.35-Cr0.25-Si0.2-Al0.2casting alloy and Ta metal. Electrical properties and microstructures of Ni-Cr-Si-Al-Ta films under different sputtering powers and annealing temperatures were investigated. The phase evolution, microstructure, and composition of Ni-Cr-Si-Al-Ta films were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Auger electron spectroscopy (AES). When the annealing temperature was set to 300°C, the Ni-Cr-Si-Al-Ta films with an amorphous structure were observed. When the annealing temperature was at 500°C, the Ni-Cr-Si-Al-Ta films crystallized into Al0.9Ni4.22, Cr2Ta, and Ta5Si3phases. The Ni-Cr-Si-Al-Ta films deposited at 100 W and annealed at 300°C which exhibited the higher resistivity 2215 μΩ-cm with −10 ppm/°C of temperature coefficient of resistance (TCR).


2011 ◽  
Vol 80-81 ◽  
pp. 217-220 ◽  
Author(s):  
Xue Qing Yue ◽  
Hai Jun Fu ◽  
Da Jun Li

Graphite encapsulated nickel nanoparticles were prepared by ball milling andsubsequently annealing a mixture of expanded graphite with nickel powders. The products were characterized by transmission electron microscope and X-ray diffraction. The formation mechanism of the products was discussed. Results show that the products have a size range of 20-150 nm. The graphite and nickel in the products all exhibit a high crystallinity.


2019 ◽  
Vol 8 (1) ◽  
pp. 590-599 ◽  
Author(s):  
Kaushik Roy ◽  
Ambikesh K. Srivastwa ◽  
Chandan K. Ghosh

Abstract In this report, we present a simple and unexplored procedure for green synthesis of silver nanoparticles featuring exudation of Euphorbia acruensis along with the study of its antibacterial and anticoagulant properties. Analytical techniques like ultraviolet visible spectroscopy (UV-Vis), X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) were used to analyse the production, crystallinity and morphology of bio-reduced silver nanoparticles. The antibacterial study was performed by following standard disc diffusion method. Most importantly, the anticoagulant and thrombolytic activities of biogenic silver nanoparticles were evaluated by addition of nanoparticles to human blood samples under practical conditions. These green synthesized silver nanoparticles were found to have potent antibacterial, anticoagulant and thrombolytic properties which make them an attractive choice for future medical applications.


NANO ◽  
2016 ◽  
Vol 11 (07) ◽  
pp. 1650079 ◽  
Author(s):  
Wenjun Yan ◽  
Ming Hu ◽  
Jiran Liang ◽  
Dengfeng Wang ◽  
Yulong Wei ◽  
...  

A novel composite of Au-functionalized porous silicon (PS)/V2O5 nanorods (PS/V2O5:Au) was prepared to detect NO2 gas. PS/V2O5 nanorods were synthesized by a heating process of pure vanadium film on PS, and then the obtained PS/V2O5 nanorods were functionalized with dispersed Au nanoparticles. Various analytical techniques, such as field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), have been employed to investigate the properties of PS/V2O5:Au. Herein, the PS/V2O5:Au sample exhibited improved NO2-sensing performances in response, stability and selectivity at room temperature (25[Formula: see text]C), compared with the pure PS/V2O5 nanorods. These phenomena were closely related to not only the dispersed Au nanoparticles acting as a catalyst but also the p-n heterojunctions between PS and V2O5 nanorods. Whereas, more Au nanoparticles suppressed the improvement of response to NO2 gas.


1991 ◽  
Vol 230 ◽  
Author(s):  
Toyohiko J. Konno ◽  
Robert Sinclair

AbstractThe crystallization of amorphous Si in a Al/Si multilayer (with a modulation length of about 120Å) was investigated using transmission electron microscopy, differential scanning calorimetry and X-ray diffraction. Amorphous Si was found to crystallize at about 175 °C with the heat of reaction of 11±2(kJ/mol). Al grains grow prior to the nucleation of crystalline Si. The crystalline Si was found to nucleate within the grown Al layers. The incipient crystalline Si initially grows within the Al layer and then spreads through the amorphous Si and other Al layers. Because of extensive intermixing, the original layered structure is destroyed. The Al(111) texture is also enhanced.


1988 ◽  
Vol 132 ◽  
Author(s):  
E. Hellstern ◽  
H. J. Fecht ◽  
C. Garland ◽  
W. L. Johnson ◽  
W. M. Keck

ABSTRACTWe investigated through X- ray diffraction and transmission electron microscopy the crystal refinement of the intermetallic compound AIRu by high- energy ball milling. The deformation process causes a decrease of crystal size to 5–7 rum and an increase of atomic level strain. This deformation is localized in shear bands with a thickness of 0.5 to 1 micron. Within these bands the crystal lattice breaks into small grains with a typical size of 8–14 rum. Further deformation leads to a final nanocrystalline structure with randomly oriented crystallite grains separated by high- angle grain boundaries.


2014 ◽  
Vol 614 ◽  
pp. 35-40
Author(s):  
Bogdan Istrate ◽  
Corneliu Munteanu ◽  
Sorin Iacob Strugaru ◽  
Alexandru Barca ◽  
Carmen Biniuc ◽  
...  

The objective of this work is to understand the influence of time on thermal oxidation of CP-Ti Grade II at 850 oC. Thermal treatments were performed for 5 minutes, 15 minutes, 30 minutes, 60 minutes and 120 minutes of isothermal stage. The response of titanium to oxidation at same temperatures and various timings has been investigated, in terms of layer thickness, phase evolution. A variety of experimental and analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM) and ball cratering test have been used to characterize the result of thermal oxidized surfaces. The results showed that oxygen diffused on Ti structure can produce a thick oxide layer with rutile (TiO2) between 3,50 and 10,34 microns, which exhibited good adhesion with the substrate.


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