Effect of Microalloying with Ti or Cr on the Corrosion Behavior of Al-Ni-Y Amorphous Alloys

CORROSION ◽  
10.5006/2451 ◽  
2017 ◽  
Vol 74 (1) ◽  
pp. 66-74 ◽  
Author(s):  
L.M. Zhang ◽  
A.L. Ma ◽  
H.X. Hu ◽  
Y.G. Zheng ◽  
B.J. Yang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Photoelectron Spectroscopy ◽  
Amorphous Alloys ◽  
Diffusion Mechanism ◽  
High Surface ◽  
Control Sample ◽  
Surface Concentration ◽  
Passive Films ◽  
High Surface Concentration

The effect of microalloying with Ti or Cr on the corrosion behavior of Al-Ni-Y amorphous alloys in 0.1 M NaCl solution was studied by potentiodynamic polarization, Mott-Schottky, and x-ray photoelectron spectroscopy techniques. Microalloying with Ti or Cr could greatly improve the corrosion resistance of Al-Ni-Y amorphous alloys. A high surface concentration of Ti or Cr in the passive films was detected, which should be responsible for the improved corrosion resistance compared to the control sample. The possible process of Ti or Cr involved in the passive films was proposed in terms of the point defect model and the vacancy diffusion mechanism. Furthermore, the effect of Ti was stronger than Cr because of the higher film resistance as well as the higher surface concentration. The different passivation abilities and atomic radiuses between Ti and Cr were presented to explain the better microalloying effect of Ti compared to Cr.

scholarly journals Study on Corrosion Behavior of Ultrafine-Grained Ti-6Al-7Nb Fabricated by Equal Channel Angular Pressing

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 950 ◽  
Author(s):  
Zequn Yu ◽  
Yuecheng Dong ◽  
Xin Li ◽  
Jingzhe Niu ◽  
Igor Alexandrov ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Oxide Film ◽  
Equal Channel Angular Pressing ◽  
Corrosion Behavior ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Electrochemical Measurement ◽  
Coarse Grained ◽  
Angular Pressing ◽  
Ultrafine Grained

The aim of this study was to investigate the corrosion resistance of ultrafine-grained (UFG) Ti-6Al-7Nb fabricated by equal channel angular pressing (ECAP) and coarse-grained (CG) Ti- 6Al- 7Nb. The microstructure of each specimen was investigated by the electron backscattered diffraction (EBSD) method. The corrosion behavior of each specimen was determined by electrochemical measurement in Ringer’s solution. The surface corroded morphologies and oxide film formed on Ti-6Al-7Nb alloy after electrochemical measurement were investigated by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). EBSD investigation shows that the grain size of UFG Ti-6Al-7Nb decreased to ~0.4 µm, accompanied by low angle grain boundaries (LAGBs) accounting for 39%. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) results indicated that UFG Ti-6Al-7Nb alloy possessed a better corrosion resistance. The surface corroded morphologies revealed many small and shallow corrosion pits, which can be attributed to the good compactness of the oxide film and a rapid self- repairing ability of the UFG Ti-6Al-7Nb alloy.

A Steady-State Model for Coupled Defect Impurity Diffusion in Silicon

1989 ◽  
Vol 163 ◽  
Author(s):  
F. F. Morehead ◽  
R. F. Lever
Keyword(s):  
Steady State ◽  
High Surface ◽  
Local Equilibrium ◽  
Surface Concentration ◽  
Extended Model ◽  
High Concentration ◽  
Steady State Model ◽  
High Surface Concentration ◽  
Phosphorus In Silicon ◽  
Diffusion Profiles

AbstractWe extend our earlier model which was proposed to explain tails in the diffusion profiles of high concentration boron and phosphorus in silicon. Our quasi-steady-state approach is generalized here to include both vacancies (V) and interstitials (I) at equivalent levels. I-V recombination is regarded as near local equilibrium, occurring through reactions of the defects with defect-impurity pairs. This approach leads to the well-known plateau, kink and tail in high surface concentration P diffusions in Si and to the less well recognized tails in B as well. Our extended model, in its simplest form, allows a more complete and less restrictive treatment of Au diffusion in Si. An important advantage is the direct inclusion of these defect-impurity interactions and the resulting gradients in the defect concentrations.

A New Model of Tail Diffusion of Phosphorus and Boron in Silicon

1985 ◽  
Vol 52 ◽  
Author(s):  
Frederick F. Morehead ◽  
R. F. Lever
Keyword(s):  
Concentration Profile ◽  
Process Simulation ◽  
Low Temperatures ◽  
High Surface ◽  
Surface Concentration ◽  
Transient Effects ◽  
Phosphorus Diffusion ◽  
High Surface Concentration ◽  
Conventional Models ◽  
Normal Processing

ABSTRACTIt is well known that high surface concentration phosphorus diffusion leads to deeply penetrating “tails” in its concentration profile. At 700 °C the tail diffusivity exceeds that of low concentration phosphorus by a factor of a thousand. Less spectacular, but very significant tailing also affects tioron, making the conventional models contained in commonly available process simulation programs quite inaccurate for boron diffusions with high surface concentrations. We show that the observed tailing can be accounted for by a model whose central assumption is the local equality of dopant and oppositely directed defect fluxes. As predicted by the model, the effect is greatest for normal processing at low temperatures for high surface concentrations. It is minimal for the high temperatures of rapid thermal annealing and unrelated to transient effects.

Effect of RE Elements Addition on Corrosion Behavior of Mg-Zn-Ca Amorphous Alloys for Biomedical Applications

2021 ◽  
Vol 1035 ◽  
pp. 501-510
Author(s):  
Yu Chen Chi ◽  
Bao Ru Guan ◽  
Feng Chen ◽  
Feng Xinag Qin
Keyword(s):  
Thermal Stability ◽  
Corrosion Resistance ◽  
Rare Earth ◽  
Oxide Layer ◽  
Corrosion Behavior ◽  
Amorphous Alloys ◽  
Biomedical Applications ◽  
Good Thermal Stability ◽  
Re Elements

The effects of rare earth (RE) elements (La, Y) addition on thermal stability and corrosion behavior of Mg68Zn28Ca4 amorphous alloys were investigated in this paper. The investigated Mg-Zn-Ca-RE amorphous alloys exhibit good thermal stability and enhanced corrosion resistance. The enhanced corrosion resistance of the RE-containing amorphous alloys is owing to the enrichment of the Zn and RE elements in the oxide layer. The corrosion resistance is further improved with the increasing of RE content.

Fabrication of Ultra-Shallow P+-N and N+-P Junctions by Diffusion From Selectively Deposited, Ion-Implanted and In-Situ Doped Si0.7Ge0.3

1993 ◽  
Vol 303 ◽  
Author(s):  
D.T. Grider ◽  
M.C. ÖztÜrk ◽  
J.J. Wortman ◽  
G.S. Harris ◽  
D.M. Maher
Keyword(s):  
High Surface ◽  
Chemical Vapor ◽  
Surface Concentration ◽  
Shallow Junctions ◽  
High Surface Concentration ◽  
Diffusion Source ◽  
Ultra Shallow Junctions ◽  
P Type ◽  
Ion Implanted

ABSTRACTSelectively deposited Si0.7Ge0.3 has been investigated as a potential diffusion source for fabricating ultra-shallow junctions in Si. Rapid thermal chemical vapor deposition (RTCVD) was used to selectively deposit Si0.7Ge0.3 on Si using SiH2C12, GeH4, and H2. Both ionimplanted and in-situ doped Si0.7Ge0.3 were considered as a diffusion source for fabricating ultra-shallow junctions. In-situ doping was achieved with B2H6 and PH3 for p-type and n-type doping, respectively. Boron and phosphorus diffusion in ion-implanted Si0.7Ge0.3 was investigated and modeled using SSUPREM4. Diffusion from implanted and in-situ doped Si0.7Ge0.3 in Si was also studied and modeled. Boron diffusivities in Si0.7Ge0.3 were found to be approximately 10 times greater than in Si, while phosphorus diffusivities were over 100 times greater in Si0.7Ge0.3. The faster dopant diffusivities in Si0.7Ge0.3 allow high surface concentration, abrupt diffusion profiles to be formed in Si. Gated, p-n junction diodes with junction depths as shallow as 140Å were fabricated and tested to study the quality of the diffusions from Si0.7Ge0.3.

Fluorescent Reactive Core–Shell Composite Nanoparticles with A High Surface Concentration of Epoxy Functionalities

2008 ◽  
Vol 20 (1) ◽  
pp. 317-325 ◽  
Author(s):  
Volodymyr Tsyalkovsky ◽  
Viktor Klep ◽  
Karthik Ramaratnam ◽  
Robert Lupitskyy ◽  
Sergiy Minko ◽  
...  
Keyword(s):  
High Surface ◽  
Surface Concentration ◽  
Composite Nanoparticles ◽  
Core Shell ◽  
High Surface Concentration ◽  
Shell Composite

Corrosion Behavior and Microstructure of Pd Ions Doped Cerium Conversion Coating on AA2219-T87 Aluminum Alloy

2015 ◽  
Vol 1090 ◽  
pp. 79-83
Author(s):  
Yan Hong He ◽  
Zhen Duo Cui ◽  
Xian Jin Yang ◽  
Sheng Li Zhu ◽  
Zhao Yang Li ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Corrosion Behavior ◽  
Photoelectron Spectroscopy ◽  
Composite Coatings ◽  
Corrosion Current ◽  
Conversion Coating ◽  
X Ray Diffraction ◽  
X Ray ◽  
Excellent Corrosion Resistance

In this paper, Pd ions doped cerium conversion coating (CeCC/Pd) was deposited on AA2219-T87 aluminum alloy by electroplating. The microstructure and composition of the coating were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS). Corrosion behavior of AA2219-T87 aluminum alloy with the coating was investigated in 3.5wt.% NaCl solution at the room temperature. XRD and XPS results indicate the existence of cerium-oxide and palladium-oxide in the CeCC/Pd. Polarization curves show that the CeCC/Pd exhibits excellent corrosion resistance. The corrosion current density of the CeCC/Pd decreases by two orders of magnitude compared with the CeCC. The improvement of corrosion resistance would be attributed to the small grain size, good compactness and adhesive strength of the composite coatings.

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