Microstructure of TiC/Amorphous Hydrocarbon Nanocomposite Coatings

2000 ◽  
Vol 6 (S2) ◽  
pp. 440-441
Author(s):  
D. M. Cao ◽  
J. C. Jiang ◽  
B. Feng ◽  
W. J. Meng

Application of an appropriate ceramic surface coating to mechanical components such as bearings and gears can provide longer life and increased performance reliability. Metal-containing hydrocarbon (Me-C:H) coatings possess high hardness, together with low friction and low wear rate. They have also been suggested to adhere better to metallic substrates. This combination of attractive mechanical/tribological properties makes Me-C:H coatings potentially useful for surface modification of a wide range of mechanical components.Using the technique of inductively coupled plasma (ICP) assisted vapor deposition[1], we have synthesized Ti-containing hydrocarbon (Ti-C:H) coatings with a wide range of Ti compositions[2]. Coating mechanical properties such as modulus and hardness have been measured by the technique of nanoindentation and correlated to Ti and hydrogen compositions[2,3].We have performed detailed microstructural examination of Ti-C:H coatings by transmission electron microscopy (TEM), Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy, and X-ray Absorption Near Edge Structure (XANES) spectroscopy.

2006 ◽  
Vol 72 (9) ◽  
pp. 6414-6416 ◽  
Author(s):  
Laure Avoscan ◽  
Richard Collins ◽  
Marie Carriere ◽  
Barbara Gouget ◽  
Jacques Cov�s

ABSTRACT The accumulated organic form of selenium previously detected by X-ray absorption near-edge structure (XANES) analyses in Cupriavidus metallidurans CH34 exposed to selenite or selenate was identified as seleno-l-methionine by coupling high-performance liquid chromatography to inductively coupled plasma-mass spectrometry.


Nanomaterials ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 44
Author(s):  
Do-Gak Jeung ◽  
Tae-Hyun Kim ◽  
Jae-Min Oh

Trivalent gallium ion was successfully incorporated into chemically well-defined MgAl-layered double hydroxide (LDH) frameworks through postsynthetic hydrothermal treatment. Quantitative analysis with inductively coupled plasma-mass spectroscopy exhibited that Ga3+ was first incorporated into LDH through partial dissolution-precipitation at the edge of LDH particle and homogeneously distributed throughout the particle by substitution of Ga3+ for Al3+ in LDH frame works. The powder X-ray diffraction patterns showed that the Ga3+ incorporation did not affect the crystal structure without evolution of unexpected impurities. The morphology and surface property of LDH evaluated by scanning electron microscopy and light scattering showed the preservation of physicochemical properties throughout 24 h of hydrothermal reaction. The distribution of incorporated Ga3+ was visualized with energy dispersive spectroscopy-assisted transmission electron microscopy, suggesting the homogeneous location of Ga3+ in an LDH particle. The X-ray absorption near-edge structure and extended X-ray absorption fine structure suggested that the Ga moiety was immobilized in LDH from 0.5 h and readily crystallized upon reaction time.


Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 463
Author(s):  
Habib Ur Rehman ◽  
Gerhard Martens ◽  
Ying Lai Tsai ◽  
Chawalit Chankhantha ◽  
Pinit Kidkhunthod ◽  
...  

Kunzite, the pink variety of spodumene is famous and desirable among gemstone lovers. Due to its tenebrescent properties, kunzite always remains a hot research candidate among physicists and mineralogists. The present work is continuing the effort towards value addition to kunzite by enhancing its color using different treatments. Before color enhancement, it is essential to identify the chromophores and their oxidation states. In this paper, the authors investigated the main impurities in natural kunzite from the Nuristan area in Afghanistan and their valence states. Some impurities in the LiAlSi2O6 spodumene structure were identified and quantified by using sensitive techniques, including Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), UV−VIS and X-ray absorption near-edge structure (XANES). LA-ICP-MS indicated many trace elements as impurities in kunzite, among which Fe and Mn are the main elements responsible for coloration. The oxidation states of these two transition elements were determined by the XANES technique. The study reveals that Mn is present in both Mn2+ and Mn3+ oxidation states, while Fe is present only in Fe3+ oxidation state.


2002 ◽  
Vol 17 (10) ◽  
pp. 2628-2632 ◽  
Author(s):  
W. J. Meng ◽  
X. D. Zhang ◽  
B. Shi ◽  
R. C. Tittsworth ◽  
L. E. Rehn ◽  
...  

A series of Ti–Si–N coatings with 0 < Si < 20 at.% were synthesized by inductively coupled plasma assisted vapor deposition. Coating composition, structure, atomic short-range order, and mechanical response were characterized by Rutherford backscattering spectrometry, transmission electron microscopy, x-ray absorption near-edge structure spectroscopy, and instrumented nanoindentation. These experiments show that the present series of Ti–Si–N coatings consists of a mixture of nanocrystalline titanium nitride (TiN) and amorphous silicon nitride (a-Si:N); i.e., they are TiN/a-Si:N ceramic/ceramic nanocomposites. The hardness of the present series of coatings was found to be less than 32 GPa and to vary smoothly with the Si composition.


2020 ◽  
Author(s):  
Yuta Uetake ◽  
Sachi Mouri ◽  
Setsiri Haesuwannakij ◽  
Kazu Okumura ◽  
Hidehiro Sakurai

<div>Although changing the size of metal nanoparticle (NP) is a reasonable way to tune and/or enhance their catalytic activity, size-selective preparation of NP possessing random-alloy morphology has been challenging because of the differences in the ionization potential of each metal ion. This study demonstrates a time-controlled aggregation–stabilization method for a size-selective preparation of random alloy NPs composed of Au and Pd, which are stabilized by poly(<i>N</i>-vinyl-2-pyrrolidone) (PVP). By adjusting the mixing time in the presence of a small amount of PVP, the aggregation was induced to produce AuPd:PVP with sizes ranging between 1.2 and 8.2 nm at approximately 1 nm intervals. Transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and extended x-ray absorption fine structure (EXAFS) analyses clearly indicated the formation of various sizes of AuPd nanoalloys with almost the same morphology, and size-dependent catalytic activity was observed when hydrodechlorination of 4-choroanisole was performed using 2-propanol as a reducing agent. AuPd:PVP with a size of 3.1 nm exhibited the highest catalytic activity. A comparison of the absorption edges on x-ray absorption near edge structure (XANES) spectra suggested that the electronic state of the Au and Pd species correlated with their catalytic activity, presumably affecting the rate-determining step.</div><div> </div>


2006 ◽  
Vol 71 (11) ◽  
pp. 1153-1160 ◽  
Author(s):  
Chang Hu-Yuan ◽  
Feng Li ◽  
Li. Hua ◽  
Bin Zhang

As prepared carbon nanotubes were pretreated with nitric acid (CNTs-HNO3) or ammonia (CNTs-NH3). Fourier transform infrared spectroscopy (FTIR) measurements showed that the surface of the nanotubes was functionalized with carboxylic and hydroxyl functional groups after the acid treatment and that basic groups containing nitrogen, such as N-H and C-N, were introduced to the surface of the nanotubes after the ammonia treatment. X-Ray diffraction analysis implied that the nickel residue in the CNTs was effectively removed by acid treatment. However, the nickel residue was only partially eliminated by ammonia pretreatment. NiB amorphous catalysts supported on CNTs-HNO3 and CNTs-NH3 were prepared by the impregnation-chemical reduction method and characterized by transmission electron microscopy (TEM), as well as inductively coupled plasma (ICP) spectroscopy and studied in the selective hydrogenation of acetylene. TEM measurements showed that a high density NiB particles of about 9 nm were homogeneously dispersed on the CNTs-NH3. However, NiB particles (13-23 nm)with amean size of 16 nm were scattered on the CNTs-HNO3.As a result, the activity and selectivity of NiB/CNTs-NH3 were higher than those of NiB/CNTs-HNO3 in the selective hydrogenation of acetylene.


2009 ◽  
Vol 16 (2) ◽  
pp. 247-259 ◽  
Author(s):  
Jens Kruse ◽  
Peter Leinweber ◽  
Kai-Uwe Eckhardt ◽  
Frauke Godlinski ◽  
Yongfeng Hu ◽  
...  

Synchrotron-based X-ray absorption near-edge structure (XANES) spectroscopy is becoming an increasingly used tool for the element speciation in complex samples. For phosphorus (P) almost all XANES measurements have been carried out at the K-edge. The small number of distinctive features at the P K-edge makes in some cases the identification of different P forms difficult or impossible. As indicated by a few previous studies, the P L 2,3-edge spectra were richer in spectral features than those of the P K-edge. However, experimentally consistent spectra of a wide range of reference compounds have not been published so far. In this study a library of spectral features is presented for a number of mineral P, organic P and P-bearing minerals for fingerprinting identification. Furthermore, the effect of radiation damage is shown for three compounds and measures are proposed to reduce it. The spectra library provided lays a basis for the identification of individual P forms in samples of unknown composition for a variety of scientific areas.


Author(s):  
Mark Golitko ◽  
Laure Dussubieux

Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is a versatile technique capable of measuring nearly every element on the Periodic Table down to extremely low concentrations. Using liquid sampling, it is a powerful method for bulk compositional characterization but has been only sporadically applied to archaeological ceramic studies. With laser ablation sampling, ICP-MS can be used to produce spatially resolved chemical information and has a wide range of archaeological applications including the analysis of ceramic surface treatments, paste composition, temper composition, and identification of post-burial chemical alteration. ICP-MS and LA-ICP-MS are particularly valuable when used in conjunction with bulk and mineralogical characterization techniques to elucidate which potential cultural, geological, or environmental effects are responsible for bulk compositional patterning, as well as providing complimentary compositional provenance information for individual phases of ceramic paste.


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