scholarly journals EIS Characterization of Ti Alloys in Relation to Alloying Additions of Ta

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 476
Author(s):  
Pedro P. Socorro-Perdomo ◽  
Néstor R. Florido-Suárez ◽  
Julia C. Mirza-Rosca ◽  
Mircea Vicentiu Saceleanu
Keyword(s):  
Corrosion Resistance ◽  
Biomedical Applications ◽  
Passive Layer ◽  
Scanning Tunneling ◽  
Crystallographic Structure ◽  
Tunneling Microscopy ◽  
X Ray ◽  
High Entropy ◽  
Distribution Maps ◽  
Ti Alloys

The increased popularity of Ti and its alloys as important biomaterials is driven by their low modulus, greater biocompatibility, and better corrosion resistance in comparison to traditional biomaterials, such as stainless steel and Co–Cr alloys. Ti alloys are successfully used in severe stress situations, such as Ti–6Al–4V, but this alloy is related to long-term health problems and, in response, different Ti alloys composed of non-toxic and non-allergic elements such as Nb, Zr, Mo, and Ta have been developed for biomedical applications. In this context, binary alloys of titanium and tantalum have been developed and are predicted to be potential products for medical purposes. More than this, today, novel biocompatible alloys such as high entropy alloys with Ti and Ta are considered for biomedical applications and therefore it is necessary to clarify the influence of tantalum on the behavior of the alloy. In this study, various Ti–xTa alloys (with x = 5, 15, 25, and 30) were characterized using different techniques. High-resolution maps of the materials’ surfaces were generated by scanning tunneling microscopy (STM), and atom distribution maps were obtained by energy dispersive X-ray spectroscopy (EDS). A thorough output of chemical composition, and hence the crystallographic structure of the alloys, was identified by X-ray diffraction (XRD). Additionally, the electrochemical behavior of these Ti–Ta alloys was investigated by EIS in simulated body fluid at different potentials. The passive layer resistance increases with the potential due to the formation of the passive layer of TiO2 and Ta2O5 and then decreases due to the dissolution processes through the passive film. Within the Ti–xTa alloys, Ti–25Ta demonstrates excellent passive layer and corrosion resistance properties, so it seems to be a promising product for metallic medical devices.

A study on α-RuCl3 crystal structure by scanning tunneling microscopy

1989 ◽  
Vol 47 ◽  
pp. 30-31
Author(s):  
H.-J. Cantow ◽  
H. Hillebrecht ◽  
S. Magonov ◽  
H. W. Rotter ◽  
G. Thiele
Keyword(s):  
Crystal Structure ◽  
Density Distribution ◽  
Scanning Tunneling Microscopy ◽  
Electron Density ◽  
Structure Determination ◽  
Electron Density Distribution ◽  
Scanning Tunneling ◽  
Monoclinic Space Group ◽  
Tunneling Microscopy ◽  
X Ray

From X-ray analysis, the conclusions are drawn from averaged molecular informations. Thus, limitations are caused when analyzing systems whose symmetry is reduced due to interatomic interactions. In contrast, scanning tunneling microscopy (STM) directly images atomic scale surface electron density distribution, with a resolution up to fractions of Angstrom units. The crucial point is the correlation between the electron density distribution and the localization of individual atoms, which is reasonable in many cases. Thus, the use of STM images for crystal structure determination may be permitted. We tried to apply RuCl3 - a layered material with semiconductive properties - for such STM studies. From the X-ray analysis it has been assumed that α-form of this compound crystallizes in the monoclinic space group C2/m (AICI3 type). The chlorine atoms form an almost undistorted cubic closed package while Ru occupies 2/3 of the octahedral holes in every second layer building up a plane hexagon net (graphite net). Idealizing the arrangement of the chlorines a hexagonal symmetry would be expected. X-ray structure determination of isotypic compounds e.g. IrBr3 leads only to averaged positions of the metal atoms as there exist extended stacking faults of the metal layers.

scholarly journals Interface morphology of a Cr(001)/Fe(001) superlattice determined by scanning tunneling microscopy and x-ray diffraction: A comparison

2001 ◽  
Vol 89 (1) ◽  
pp. 181-187 ◽  
Author(s):  
C. M. Schmidt ◽  
D. E. Bürgler ◽  
D. M. Schaller ◽  
F. Meisinger ◽  
H.-J. Güntherodt ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Scanning Tunneling ◽  
Interface Morphology ◽  
X Ray Diffraction ◽  
Tunneling Microscopy ◽  
X Ray

scholarly journals Structural determination of the Si(111) √3×√3-Bi surface by x-ray standing waves and scanning tunneling microscopy

1994 ◽  
Vol 50 (16) ◽  
pp. 12246-12249 ◽  
Author(s):  
J. C. Woicik ◽  
G. E. Franklin ◽  
Chien Liu ◽  
R. E. Martinez ◽  
I.-S. Hwong ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Standing Waves ◽  
Scanning Tunneling ◽  
Structural Determination ◽  
Tunneling Microscopy ◽  
X Ray

Role of chromium in anomalous behaviour of the passive layer in Ni-Cr-Mo alloys in 1M HCl solution

CORROSION ◽  
10.5006/3767 ◽  
2022 ◽  
Author(s):  
Malvika Karri ◽  
Amit Verma ◽  
J.B. Singh ◽  
Sunil Kumar Bonagani ◽  
U.K. Goutam
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Underlying Mechanism ◽  
Passive Layer ◽  
X Ray ◽  
Superior Corrosion Resistance ◽  
Hcl Solution ◽  
Cr2o3 Layer

This work seeks to understand the underlying mechanism involved in passivity of Ni-Cr-Mo alloys in a less concentrated HCl solution (1M) by systematically varying contents of Cr and Mo solutes in model Ni-Cr-Mo alloys. Corrosion behaviour was evaluated based on potentiodynamic polarisation tests carried out in conjunction with electrochemical impedance and x-ray photoelectron spectroscopies of passive films that formed on alloys during their exposure to the HCl solution. Results have shown that an increase in Mo alone is not sufficient to improve the corrosion resistance of the alloys at lower concentrations of HCl. Optimum concentrations of Cr and Mo solutes have been found to be in the vicinity of ~17 wt.% Cr and ~19 wt.% Mo for superior corrosion resistance of the alloys. This was attributed to the protection of the Cr2O3 layer as a consequence of the enrichment of Mo6+ ions in the passive film in 1M HCl solution.

Hard X-ray beam damage study of monolayer Ni islands using SX-STM

2015 ◽  
Vol 1754 ◽  
pp. 135-140 ◽  
Author(s):  
Nozomi Shirato ◽  
Marvin Cummings ◽  
Heath Kersell ◽  
Yang Li ◽  
Dean Miller ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Scanning Tunneling ◽  
X Rays ◽  
Tunneling Microscopy ◽  
X Ray ◽  
Induced Changes ◽  
Metal Islands ◽  
Beam Damage ◽  
Damage Study

ABSTRACTX-ray beam-induced damage in nanoscale metal islands was investigated. Monolayer-high Ni islands were prepared on a Cu(111) substrate. High brilliance X-rays with photon energies between 8.45 and 8.85 keV illuminated the sample for about 11 hours. In order to track changes in the morphology of the islands, the synchrotron X-ray scanning tunneling microscopy (SX-STM) technique was utilized. The result shows that X-ray illumination onto Ni islands does not induce noticeable damage. The study demonstrates that local beam-induced changes can be studied using SX-STM.

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