Oxidation Kinetics of Mg-, Si-, and Fe-Implanted Aluminum by Using X-ray Photoelectron Spectroscopy

1999 ◽  
Vol 103 (13) ◽  
pp. 2402-2407 ◽  
Author(s):  
T. Do ◽  
N. S. McIntyre ◽  
P. A. W. van der Heide ◽  
U. G. Akano
1999 ◽  
Vol 567 ◽  
Author(s):  
A. Y. Mao ◽  
J. Lozano ◽  
J. M. White ◽  
D. L. Kwong

ABSTRACTThe oxidation kinetics of ultra thin thermally NH3-nitrided Si3N4 films in N2O ambient has been extensively studied using angle resolved x-ray photoelectron spectroscopy (ARXPS). Ultra thin (7Å) Si3N4 films formed by RTP nitridation of Si in NH3 were annealed in N2O at various temperatures (700 °C - 1000 °C) for 30 sec. ARXPS showed that Si substrate at the Si-Si3N4 interface was oxidized when annealed at 1000 °C for 30 sec, and was accompanied by the oxidation of the top Si3N4 surface. The total film thickness increases 4–5 times of that of the original Si3N4 layer. However, the oxide formed on the top Si3N4 surface is twice as thick as that formed at the Si3N4/Si interface. No interfacial oxide was found when annealing below 900°C, although the formation of the silicon oxide and oxynitride above the Si3N4 layer was still observed.


1999 ◽  
Vol 06 (06) ◽  
pp. 1053-1060 ◽  
Author(s):  
N. TABET ◽  
J. AL-SADAH ◽  
M. SALIM

X-ray Photoelectron Spectroscopy (XPS) has been used to investigate the oxidation of (011) Ge substrates. The sample surfaces were CP4-etched, then annealed in situ, at different temperatures, for various durations. Dry and wet atmospheres were used. The oxidation rate during the early stage was increased by the presence of moisture in the atmosphere. A simple model was used to define and determine an apparent thickness of the oxide film from XPS measurements. The time dependence of the apparent thickness is consistent with a partial coverage of the surface by oxide islands. The growth kinetics of the oxide islands obeys a nearly cubic law.


2005 ◽  
Vol 20 (6) ◽  
pp. 1396-1403 ◽  
Author(s):  
C.Y. Tam ◽  
C.H. Shek

The oxidation kinetics of Cu60Zr30Ti10 bulk metallic glass and its crystalline counterpart were studied in oxygen environment over the temperature range of 573–773 K. The oxidation kinetics, measured with thermogravimetric analysis, of the metallic glass follows a linear rate law between 573 and 653 K and a parabolic rate law between 673 and 733 K. It was also found that the oxidation activation energy of metallic glass is lower than that of its crystalline counterpart. The x-ray diffraction pattern showed that the oxide layer is composed of Cu2O, CuO, ZrO2, and metallic Cu. Cu enrichment on the topmost oxide layer of the metallic glass oxidized at 573 K was revealed by x-ray photoelectron spectroscopy while there was a decrease in Cu content in the innermost oxide layer. The oxide surface morphologies observed from scanning electron microscopy showed that ZrO2 granules formed at low temperatures while whiskerlike copper oxides formed at higher temperatures.


2020 ◽  
Vol 81 (10) ◽  
pp. 2270-2280
Author(s):  
Yonggang Xu ◽  
Tianxia Bai ◽  
Yubo Yan ◽  
Yunfeng Zhao ◽  
Ling Yuan ◽  
...  

Abstract It is of great significance to remove Cr(VI) from water as a result of its high toxicity. Biochar from corn straw was modified by different acids (HNO3, H2SO4 and H3PO4) to remove Cr(VI) from aqueous solution. To estimate the removal mechanisms of Cr(VI) by the acid-modified biochars, batch experiments were performed in the light of contact time, Cr(VI) concentration, and pH, and the characteristics of acid-modified biochars before and after Cr(VI) adsorption were investigated by Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS). The adsorption kinetics of Cr(VI) by acid-modified biochars were consistent with the pseudo-second-order model, and the adsorption isotherm obeyed the Freundlich model. Furthermore, the acid- modified biochars could supply more oxygen-containing functional groups (-COOH and -OH) as electron donor (e−) and hydrogen ion (H+) to enhance the reduction of Cr(VI) to Cr(III), resulting in enhanced removal of Cr(VI). HNO3-modified biochar exhibited the highest removal efficiency of Cr(VI). In general, the acid modifition of biochar was an effective method to increase the removal of Cr(VI).


2010 ◽  
Vol 256 (23) ◽  
pp. 7178-7185 ◽  
Author(s):  
K. McLeod ◽  
S. Kumar ◽  
N.K. Dutta ◽  
R.St.C. Smart ◽  
N.H. Voelcker ◽  
...  

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