105 research outputs found
Complex study of H-induced structural rearrangements in FeZr glasses
Microstructural changes and relaxation processes were examined in Fe-Zr based rapidly
solidified samples. These phenomena occur far below crystallization temperature in the course of
heat treatment, or even at room temperature, induced by absorbed hydrogen
Comparison of direct and indirect structural analysis of HAZ after laser cutting in amorphous alloys
Sputtered nanocrystalline ceramic TiC / amorphous C thin films as potential materials for medical applications
The relationship between structural behaviour of sp
uttered TiC / amorphous C (TiC /a:C) thin
films and corrosion properties was measured in thre
e various pH solutions (0.5 M NaCl
(pH=6); 0.1 M HCl (pH=1); 0.1 M NaOH (pH=13). The ~
400 nm thick nanocomposites were
deposited by DC magnetron sputtering on different s
ubstrates (Ti6Al4V alloy and CoCrMo
alloy) in argon at 25 C° and 0.25 Pa with 150 W inp
ut power of carbon target and 50 W input
power of titanium target. The structure and composi
tion of nanocomposites were investigated
by Transmission and Scanning Electron Microscopy. I
n both samples the structural
investigations confirmed columnar structure of TiC
/a:C films with 25-50 nm sized cubic TiC.
These columns were separated by 2 - 3 nm thin amorp
hous carbon layers. TiC /a:C /Ti6Al4V
alloy implant material showed better corrosion resi
stance than the TiC /a:C /CoCrMo alloy in
0.5 M NaCl solution based on results of the Electro
chemical Impedance Spectroscopy. For
both samples, the 0.1 M NaOH solution was the most
corrosive media
The Contact Angle Between Ag-Based Melts and Graphite Substrate and the Texture Evolution During the Subsequent Solidification
Ag based alloys are widely used in the modern brazing technologies for the substitution of tin-lead based alloys. In the present work the wetting ability between graphite substrate and diluted Ag-M (M: Cd, In, Sn, Sb) has been studied using the sessile drop method. The contact angle between the liquids and solid substrate was measured at 1200˚C. Subsequently the micro structure of the solidified drops was investigated applying X-ray diffraction (XRD) and transmission electron microscopic (TEM) measurements. A texture formation was found in the substrate/drop interface region. Comparing the values of the contact angles measured on the Ag- M samples with the degree of the texture determined by XRD it was found, that the contact angle is smaller the degree of texture higher
Determination of the Complex Dielectric Function of Ion-Implanted Amorphous Germanium by Spectroscopic Ellipsometry
Accurate reference dielectric functions play an important role in the research and development of optical materials. Libraries of such data are required in many applications in which amorphous semiconductors are gaining increasing interest, such as in integrated optics, optoelectronics or photovoltaics. The preparation of materials of high optical quality in a reproducible way is crucial in device fabrication. In this work, amorphous Ge (a-Ge) was created in single-crystalline Ge by ion implantation. It was shown that high optical density is available when implanting low-mass Al ions using a dual-energy approach. The optical properties were measured by multiple angle of incidence spectroscopic ellipsometry identifying the Cody-Lorentz dispersion model as the most suitable, that was capable of describing the dielectric function by a few parameters in the wavelength range from 210 to 1690 nm. The results of the optical measurements were consistent with the high material quality revealed by complementary Rutherford backscattering spectrometry and cross-sectional electron microscopy measurements, including the agreement of the layer thickness within experimental uncertainty
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