Influence of Ion Implantation of Several Elements on Oxidation Behavior of TiAl

2006 ◽  
Vol 522-523 ◽  
pp. 633-640 ◽  
Author(s):  
Michiko Yoshihara ◽  
Shigeji Taniguchi ◽  
D. Furumaki ◽  
M. Aono
Keyword(s):  
Ion Implantation ◽  
Atmospheric Pressure ◽  
Oxidation Behavior ◽  
Alumina Scale ◽  
Complex Oxide ◽  
Oxidation Products ◽  
X Ray ◽  
Cyclic Oxidation Test ◽  
Initial Stage ◽  
Acceleration Voltage

TiAl-based alloys have attractive properties as light weight heat-resisting material. In the present work, the influence of Cu, Zn, Ag and Se on the oxidation behavior of TiAl was investigated by ion implantation at acceleration voltage of 50 kV and ion doses of 1019 to 2x1021 ions/m2. The oxidation behavior was assessed by a cyclic oxidation test at 1200 K in a flow of purified oxygen under atmospheric pressure. The oxidation products were analyzed by conventional methods including X-ray diffractometry, SEM and EPMA. The implantation of Zn and Cu improves the oxidation resistance significantly by forming virtually Al2O3 scales, while Ag and Se enhance the oxidation. The improvement by Zn is attributable to the formation of complex oxide of Zn in the initial stage of oxidation. The oxygen partial pressure under the layer seems to be very low, resulting in the formation of alumina scale due to a selective oxidation of Al. The influence of Cu is not certain. The influence of Ag and Se is explained in terms of Al depletion in the implanted layer.

INFLUENCE OF ION IMPLANTATION ON OXIDATION BEHAVIOR OF TiAl

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4667-4672 ◽  
Author(s):  
MICHIKO YOSHIHARA ◽  
SHIGEJI TANIGUCHI
Keyword(s):  
Ion Implantation ◽  
Selective Oxidation ◽  
Oxidation Behavior ◽  
Complex Oxide ◽  
The Other ◽  
Alloying Elements ◽  
Implantation Technique ◽  
Other Hand ◽  
Initial Stage ◽  
Cu And Zn

The influence of alloying elements on oxidation behavior of TiAl has been investigated using an ion-implantation technique and the mechanisms were discussed. The influence can be classified into several groups according to their effects. The implantation of β-forming elements, halogens, Cu and Zn results in a significant improvement of the oxidation behavior through formation of Al 2 O 3 layer in the initial stage of oxidation. The improvement by Zn is attributed to the formation of complex oxide of Zn and selective oxidation of Al beneath the layer. The implantation of Al , Si or P is also effective. On the other hand, implantation of Ag , Se and other several elements enhance the oxidation. The deterioration by Ag or Se is explained in terms of Al depletion in the implanted layer.

Influence of Micro-alloying on Oxidation Behavior of TiAl

2004 ◽  
Vol 842 ◽  
Author(s):  
Michiko Yoshihara ◽  
Shigeji Taniguchi
Keyword(s):  
Oxidation Resistance ◽  
Atmospheric Pressure ◽  
Oxidation Behavior ◽  
Doping Effect ◽  
Scale Spallation ◽  
Β Phase ◽  
Cyclic Oxidation Test ◽  
Wide Range ◽  
Modified Surface ◽  
Modified Surface Layer

ABSTRACTThe influence of a wide range of elements on oxidation behavior of TiAl was investigated by micro-alloying using ion implantation with ion doses of 1019 to 1022 m−2 and at acceleration voltages of 40 to 340kV. The oxidation resistance was assessed by a cyclic oxidation test at 1200K in a flow of purified oxygen under atmospheric pressure. The implanted elements can be classified into several groups according to their effect and mechanism. The mechanisms by which the oxidation resistance is improved are as follows: (1) Formation of a protective Al2O3 layer through β-phase formation, which was confirmed by TEM observations, in the modified surface layer by the implantation. (2) Reduction of TiO2 growth rate due to doping effect of the implanted element. (3) Protective Al2O3 layer formation through migration of volatile halide. (4) Enrichment of oxide of the implanted element in the scale. On the other hand, the oxidation resistance is decreased by (1) enhanced TiO2 growth due to doping effect, (2) lattice defects induced by the implantation, and (3) decreased scale strength and enhanced scale spallation.

Oxidation of Zr2[Al(Si)]4C5 and Zr3[Al(Si)]4C6 in air

2008 ◽  
Vol 23 (12) ◽  
pp. 3339-3346 ◽  
Author(s):  
L.F. He ◽  
Y.W. Bao ◽  
M.S. Li ◽  
J.Y. Wang ◽  
Y.C. Zhou
Keyword(s):  
Oxidation Behavior ◽  
Oxidation Products ◽  
Oxide Scales ◽  
Duplex Structure ◽  
Compact Layer ◽  
Long Period ◽  
Parabolic Law ◽  
Initial Stage ◽  
Kinetics Of ◽  
Better Than

The oxidation behavior of Zr2[Al(Si)]4C5 and Zr3[Al(Si)]4C6 in air has been investigated. The oxidation kinetics of bulk Zr2[Al(Si)]4C5 and Zr3[Al(Si)]4C6 at 900–1300 °C generally follow a parabolic law at a very short initial stage and then a linear law for a long period with the activation energy of 237.9 and 226.8 kJ/mol, respectively. The oxide scales have a duplex structure, consisting of mainly an outer porous layer of ZrO2, Al2O3, and aluminosilicate/mullite, and a thin inner compact layer of these oxides plus remaining carbon. The oxidation resistance of Zr2[Al(Si)]4C5 and Zr3[Al(Si)]4C6 has been improved compared with Zr2Al3C4, and is much better than ZrC due to larger fraction of protective oxidation products, Al2O3 and aluminosilicate/mullite.

Cellulose Extraction from Hardwood Waste of Resak (Vatica spp.)

2014 ◽  
Vol 895 ◽  
pp. 134-137 ◽  
Author(s):  
Nurul Aimi Mohd Zainul Abidin ◽  
Fauziah Abdul Aziz ◽  
Radiman Shahidan ◽  
Noriean Azraaie ◽  
Nur Amira Mamat Razali ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Electron Microscope ◽  
Atmospheric Pressure ◽  
X Ray Diffraction ◽  
Natural Polymers ◽  
Bleaching Process ◽  
X Ray ◽  
Second Stage ◽  
Initial Stage ◽  
Scanning Electron

Cellulose is one of the most important natural polymers. The aims of this study are to extract and characterize the properties cellulose from local hardwood waste, Resak (Vatica spp.). There are two main stages in the extraction of cellulose at atmospheric pressure. The initial stage is delignification and second stage is bleaching process. At the second stage, the cellulose substance are bleached in two different bleaching medium; a) sodium hydroxide (NaOH), b) acidified hydrogen peroxide (H2O2). Then, the cellulose properties of treated and untreated hardwood waste of Resak (Vatica spp.) were characterized via X-ray diffraction (XRD) and Field emission scanning electron microscope (FESEM).

scholarly journals Characterization of the Oxidation of 3D Needled C/C Composite by Synchrotron Radiation X-Ray Micro-Computed Tomography

2021 ◽  
Author(s):  
Yantao Gao ◽  
Sanfa Xin ◽  
Wenfeng Hu ◽  
Hao Yan
Keyword(s):  
Computed Tomography ◽  
Synchrotron Radiation ◽  
Nuclear Energy ◽  
Oxidation Behavior ◽  
Microstructural Characterization ◽  
Structural Components ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Initial Stage

Abstract C/C composite has been considering to be used as structural components in the field of nuclear energy. However, the material will be subjected to rapid oxidation in the air. This paper presents the microstructure evolutions of a type of high density C/C composites at 550℃ in the air. Synchrotron radiation X-ray micro-computed tomography (SR-µCT, resolution: 0.65µm) was used to characterize the microstructure in different oxidation stages. The results showed that the material was oxidized nearly homogeneous. The large pores play great rule in the oxidation behavior. The pores in the material started to extend quickly in initial stage and the number of pores and porosity were rapidly increased. In addition, it also can be seen that SR-µCT is a perspective tool for microstructural characterization, especially structure evolutions in the materials.

Oxidation of TiAl Alloys Coated by Fluorine Resin in SO2 Containing Atmosphere

2010 ◽  
Vol 654-656 ◽  
pp. 562-565
Author(s):  
Aleksander Gil ◽  
Zbigniew Żurek ◽  
Adam Stawiarski
Keyword(s):  
Mechanical Properties ◽  
Ion Implantation ◽  
Surface Treatment ◽  
Oxidation Resistance ◽  
Organic Compounds ◽  
Oxidation Behavior ◽  
Alumina Scale ◽  
Tial Alloys ◽  
Temperature Range ◽  
Halogen Effect

There are several ways to improve the oxidation resistance of TiAl alloys. One of them is alloying with elements such as Nb, Ta, W, Si, Ag, Zr or Hf. However, bulk alloying influences the mechanical properties. Surface treatment of TiAl alloys by the small amounts of halogens leads to the formation of the protective alumina scale (“halogen effect”). The halogens can be applied by ion techniques (ion implantation, plasma immersion implantation) but also by spraying or dipping with halogen-containing inorganic and organic compounds. Deposition of the fluorine-containing resin on the surface of TiAl alloys is the easiest way to achieve the best results. SO2 impurity in air significantly influences oxidation behavior of TiAl alloys. In this work the results of the oxidation of a Ti-48Al-2Cr alloy coated with a fluorine-containing resin in the synthetic air and air containing 1% SO2 were presented. The oxidation runs were carried out in the temperature range 800-1000°C.

The Oxidation Behavior of the √3×√3 Ag and Au/Si(111) Surfaces at Room Temperature Studied by Photoemission

1985 ◽  
Vol 54 ◽  
Author(s):  
J. J. Yeh ◽  
D. J. Friedman ◽  
R. Cao ◽  
J. Hwang ◽  
J. Nogami ◽  
...  
Keyword(s):  
Valence Band ◽  
Room Temperature ◽  
Oxidation Behavior ◽  
Photoemission Spectroscopy ◽  
Oxide Formation ◽  
Temperature Oxidation ◽  
X Ray ◽  
Initial Stage ◽  
Energy Distribution Curve ◽  
Valence Band Electron

ABSTRACTThe differences of the room temperature oxidation behavior of ordered Ag/Si(111) and Au/Si(111) surfaces were studied by surface sensitive soft x-ray photoemission spectroscopy obtained with synchrotron radiation. Si surfaces covered with a monolayer of Ag or Au, once annealed to display a √3×√3 LEED pattern, were believed to be passivated against oxidation according to earlier reports. This work shows that these two surfaces oxidize but in a different way. Up to 104 L O2 exposures, the observed valence band of the Au/Si surface's valence band electron energy distribution curve is almost identical to that of the surface before oxygen exposure. But the corresponding Si 2p core level spectrum shows a small chemically shifted component indicating an initial stage of the formation of Si oxide. Thi3 chemically shifted signal becomes a strong peak at -3.7 eV below the clean Si position, characteristic of SiO2, after subsequent O2 exposures up to 1010 L. The Ag/Si system behaves in a similar fashion, but oxide growth saturates at 108 L, and the final oxides formed include a distribution of suboxides in addition to SiO2. Clearly, oxide formation is not prohibited by the presence of the ordered Au or Ag metal overlayer but delayed. Although the onset of oxidation is delayed compared to that for the clean Si surface, due to the metal-silicon bonding, the oxide formation is much faster once the surface starts to oxidize.

Effect of Chemical Treatment on Crystalline Cellulose: Changes in Crystallinity and Functional Groups of Cellulose

2015 ◽  
Vol 1087 ◽  
pp. 35-39 ◽  
Author(s):  
Nur Amira Mamat Razali ◽  
Noriean Azraaie ◽  
Nurul Aimi Mohd Zainul Abidin ◽  
Nur Ain Ibrahim ◽  
Fauziah Abdul Aziz ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Atmospheric Pressure ◽  
Crystalline Cellulose ◽  
Peroxyacetic Acid ◽  
Cellulosic Material ◽  
X Ray Diffraction ◽  
Cellulose I ◽  
X Ray ◽  
Second Stage ◽  
Initial Stage

Cellulosic material derived from Merbau (Intsia bijuga) was extracted at atmospheric pressure. In the initial stage the sample was delignified using peroxyacetic acid to remove the amorphous. In the second stage the samples were double bleached using hydrogen peroxide (H2O2) and sodium Hydroxide (NaOH). From the X-Ray Diffraction (XRD) data it is evident that both acid and alkali bleached celluloses have rich cellulose I structure. The results are supported by FTIR study in which all samples shown typical spectra of cellulose.

Voltage and Orientation Dependence of Characteristic X-Ray Production in Thin Crystals

1985 ◽  
Vol 43 ◽  
pp. 414-415
Author(s):  
G. Thomas ◽  
K. M. Krishnan ◽  
Y. Yokota ◽  
H. Hashimoto
Keyword(s):  
Standing Wave ◽  
Incident Beam ◽  
Orientation Dependence ◽  
Incident Plane Wave ◽  
Crystalline Materials ◽  
X Ray ◽  
Incident Plane ◽  
Crystal Unit Cell ◽  
Beam Orientation ◽  
Acceleration Voltage

For crystalline materials, an incident plane wave of electrons under conditions of strong dynamical scattering sets up a standing wave within the crystal. The intensity modulations of this standing wave within the crystal unit cell are a function of the incident beam orientation and the acceleration voltage. As the scattering events (such as inner shell excitations) that lead to characteristic x-ray production are highly localized, the x-ray intensities in turn, are strongly determined by the orientation and the acceleration voltage. For a given acceleration voltage or wavelength of the incident wave, it has been shown that this orientation dependence of the characteristic x-ray emission, termed the “Borrmann effect”, can also be used as a probe for determining specific site occupations of elemental additions in single crystals.

Layered and ion implantation specimens as possible reference materials for the electron-probe microanalysis

1992 ◽  
Vol 50 (2) ◽  
pp. 1652-1653
Author(s):  
G. Remond ◽  
R.H. Packwood ◽  
C. Gilles ◽  
S. Chryssoulis
Keyword(s):  
Ion Implantation ◽  
Reference Materials ◽  
Analytical Techniques ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
X Ray ◽  
Spatially Resolved ◽  
Analytical Expressions ◽  
Original Approach ◽  
Depth Concentration

Merits and limitations of layered and ion implanted specimens as possible reference materials to calibrate spatially resolved analytical techniques are discussed and illustrated for the case of gold analysis in minerals by means of x-ray spectrometry with the EPMA. To overcome the random heterogeneities of minerals, thin film deposition and ion implantation may offer an original approach to the manufacture of controlled concentration/ distribution reference materials for quantification of trace elements with the same matrix as the unknown.In order to evaluate the accuracy of data obtained by EPMA we have compared measured and calculated x-ray intensities for homogeneous and heterogeneous specimens. Au Lα and Au Mα x-ray intensities were recorded at various electron beam energies, and hence at various sampling depths, for gold coated and gold implanted specimens. X-ray intensity calculations are based on the use of analytical expressions for both the depth ionization Φ (ρz) and the depth concentration C (ρz) distributions respectively.

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