scholarly journals Manufacturing of Ti-6%Al and Ti-6%Al-4%V Alloys and Their Corrosion in Sodium Chloride Solutions

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 181 ◽  
Author(s):  
Hany S. Abdo ◽  
El-Sayed M. Sherif ◽  
Hamed A. El-Serehy

The current research aims at the manufacturing of Ti-6%Al alloy and Ti-6%Al-4%V alloy using the mechanical alloying method and studying their corrosion behavior after various periods of immersions in 3.5% NaCl solutions. The fabricated alloys were also evaluated using spectroscopic techniques such as X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy analyses. The corrosion behavior was studied using potentiodynamic polarization, electrochemical impedance spectroscopy, and chronoamperometric current-time electrochemical methods. It is confirmed that the presence of 4% V greatly decreases the uniform corrosion of the Ti-6%Al alloy as a result of the role of V in decreasing the cathodic, anodic, and corrosion current, and the rate of corrosion along with increasing the corrosion resistance. Increasing the time of immersion to 24 h and further to 48 h highly decreased the corrosion of the alloys. The presence of 4% V and extending the time of exposure thus increase the resistance against corrosion via decreasing the corrosion of Ti-6%Al alloy in the chloride test solution.

Author(s):  
Hayette Faid

AbstractIn this work, Zn-Ni alloys have been deposited on steel from sulfate bath, by electrodeposition method. The effect of Zn content on deposits properties was studied by cyclic voltammetry (CV), chronoaperometry (CA), linear stripping voltammetry (ALSV) and diffraction (XRD) and scanning electronic microscopy (SEM). The corrosion behavior in 3.5 wt. NaCl solution was examined using anodic polarization test and electrochemical impedance spectroscopy. X-ray diffraction of show that Zn-Ni alloys structure is composed of δ phase and γ phase, which increase with the decrease of Zn content in deposits. Results show that deposits obtained from bath less Zn2+ concentration exhibited better corrosion resistance.


2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
A. Torres-Islas ◽  
C. Carachure ◽  
S. Serna ◽  
B. Campillo ◽  
G. Rosas

The corrosion behavior of the Fe40Al60nanostructured intermetallic composition was studied using electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR) techniques with an innovative electrochemical cell arrangement. The Fe40Al60(% at) intermetallic composition was obtained by mechanical alloying using elemental powders of Fe (99.99%) and Al (99.99%). All electrochemical testing was carried out in Fe40Al60particles that were in water with different pH values. Temperature and test time were also varied. The experimental data was analyzed as an indicator of the monitoring of the particle corrosion current densityicorr. Different oxide types that were formed at surface particle were found. These oxides promote two types of surface corrosion mechanisms: (i) diffusion and (ii) charge transfer mechanisms, which are a function oficorrbehavior of the solution, pH, temperature, and test time. The intermetallic was characterized before and after each test by transmission electron microscopy. Furthermore, the results show that at the surface particles uniform corrosion takes place. These results confirm that it is possible to sense the nanoparticle corrosion behavior by EIS and LPR conventional electrochemical techniques.


Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 758 ◽  
Author(s):  
Yang ◽  
Zhang ◽  
Wang ◽  
Wang ◽  
Chen ◽  
...  

Pure Zn and Zn–ERGO composite coatings were prepared by direct current electrodeposition on 304 stainless steel. Samples were characterized by X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDS), and laser Raman spectroscopy (Raman). Results obtained have shown that the concentration of GO sheets in zinc sulfate electrolyte has an important effect on the preferred crystal orientation and the surface morphology of Zn–ERGO composite coatings. A study of the corrosion behavior of the coatings by Tafel polarization and electrochemical impedance spectroscopic (EIS) methods leads to the conclusion that the Zn-1.0 g/L ERGO composite coating possesses the best corrosion resistance compared to the pure Zn coating and other composite coatings in this study.


Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 636 ◽  
Author(s):  
Xu ◽  
Wang ◽  
Chen ◽  
Qiao ◽  
Zhang ◽  
...  

The effect of rare earth oxides on the microstructure and corrosion behavior of laser-cladding coating on 316L stainless steel was investigated using hardness measurements, a polarization curve, electrochemical impedance spectroscopy (EIS), a salt spray test, X-ray diffraction, optical microscopy, and scanning electron microscopy (SEM). The results showed that the modification of rare earth oxides on the laser-cladding layer caused minor changes to its composition but refined the grains, leading to an increase in hardness. Electrochemical and salt spray studies indicated that the corrosion resistance of the 316L stainless steel could be improved by laser cladding, especially when rare earth oxides (i.e., CeO2 and La2O3) were added as a modifier.


Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2069 ◽  
Author(s):  
Jian Ding ◽  
Xin Liu ◽  
Yujiang Wang ◽  
Wei Huang ◽  
Bo Wang ◽  
...  

The effect of Sn addition on the microstructure and corrosion behavior of extruded Mg–5Zn–4Al–xSn (0, 0.5, 1, 2, and 3 wt %) alloys was investigated by optical microscopy (OM), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical measurements, and immersion tests. Microstructural results showed that the average grain size decreased to some degree and the amount of precipitates increased with the increasing amount of Sn. The extruded Mg–5Zn–4Al–xSn alloy mainly consisted of α-Mg, Mg32(Al,Zn)49, and Mg2Sn phases as the content of Sn was above 1 wt %. Electrochemical measurements indicated that the extruded Mg–5Zn–4Al–1Sn (ZAT541) alloy presented the best corrosion performances, with corrosion potential (Ecorr) and corrosion current density (Icorr) values of −1.3309 V and 6.707 × 10−6 A·cm−2, respectively. Furthermore, the corrosion mechanism of Sn is discussed in detail.


2015 ◽  
Vol 1090 ◽  
pp. 79-83
Author(s):  
Yan Hong He ◽  
Zhen Duo Cui ◽  
Xian Jin Yang ◽  
Sheng Li Zhu ◽  
Zhao Yang Li ◽  
...  

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.


Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 11
Author(s):  
Jun Cheng ◽  
Jinshan Li ◽  
Sen Yu ◽  
Zhaoxin Du ◽  
Fuyu Dong ◽  
...  

Newly developed Ti–10Mo–6Zr–4Sn–3Nb has fascinating mechanical properties to be used as a biomedical material. However, there is still a lack of investigation focusing on the corrosion behavior of Ti–10Mo–6Zr–4Sn–3Nb. In this work, the microstructure and corrosion behavior of as-cast Ti–10Mo–6Zr–4Sn–3Nb was investigated by optical microscopy, X-ray diffraction, and electrochemical measurements. Hank’s solution was used as the electrolyte. A classical as-cast Ti–6Al–4V was used as reference. The results showed that Ti–10Mo–6Zr–4Sn–3Nb has a higher corrosion potential and a lower corrosion current density compared with Ti–6Al–4V, indicating better corrosion resistance. However, after applying anodic potentials, Ti–10Mo–6Zr–4Sn–3Nb shows larger passivation current density in both potentiodynamic polarization and potentiostatic polarization tests. This is because more alloying elements contained in Ti–10Mo–6Zr–4Sn–3Nb trigger the production of a larger number of oxygen vacancies, resulting in a higher flux of oxygen vacancy. This finding illustrates that the passive film on Ti–10Mo–6Zr–4Sn–3Nb is less protective compared with that on Ti–6Al–4V when applying an anodic potential in their passivation range.


2017 ◽  
Vol 24 (4) ◽  
pp. 547-556 ◽  
Author(s):  
Linlin Zhang ◽  
Wenxian Wang ◽  
Baocheng Wang ◽  
Peng Zhang ◽  
Hongsheng Chen

AbstractThe shot peening (SP) method was employed to modify the surface properties of 33% B4C/Al composites. The microhardness, morphology, and corrosion behavior of B4C/Al composites were characterized by using the Vickers hardness test, scanning electron microscopy, potential dynamic scanning, and electrochemical impedance spectroscopy. The experimental observations revealed that the B4C particles were embedded into the matrix, which rendered the plastic deformation of Al alloy near the surface of B4C/Al composites on the condition of the high-speed impact of projectiles. As such, the density and hardness of the B4C/Al composite modified layer near the surface were enhanced. After the SP treatment, the results of the electrochemical polarization curve test showed that the corrosion potential increased by 55.2 mV, the corrosion current changed from 3.828×10-6 to 1.102×10-6 A/cm2, and the corrosion rate decreased by 72.2%, respectively. This indicates that the corrosion resistance significantly improved via the SP treatment. The mechanism of the formation of Al alloy modified layer and electrochemical corrosion behaviors is discussed in detail.


2014 ◽  
Vol 599-601 ◽  
pp. 40-43
Author(s):  
Xia Zhao ◽  
Shuan Liu ◽  
Bao Rong Hou

Corrosion resistance of X52 pipeline steel at sea mud zone in Qingdao Huiquan test station was investigated by using Tafel polarization curves and electrochemical impedance spectroscopy (EIS). The morphology and chemical composition of the corrosion products were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results indicated that the corrosion current density of X52 pipeline steel increased with immersion time. The corrosion products were loose and mainly included Fe3O4, Fe2O3 and FeOCl, which absorbed on the specimen surface accelerating the cathodic depolarization reaction.


Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1790 ◽  
Author(s):  
Xu Zhao ◽  
Yuhong Qi ◽  
Jintao Wang ◽  
Zhanping Zhang ◽  
Jing Zhu ◽  
...  

To study the effect of cast defects on the corrosion behavior and mechanism of the UNS C95810 alloy in seawater, an investigation was conducted by weight loss determination, scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), X-ray diffraction (XRD) and electrochemical testing of the specimen with and without cast defects on the surface. The results show that the corrosion rate of the alloy with cast defects is higher than that of the alloy without cast defects, but the defects do not change the composition of the resulting corrosion products. The defects increase the complexity of the alloy microstructure and the tendency toward galvanic corrosion, which reduce the corrosion potential from −3.83 to −86.31 mV and increase the corrosion current density from 0.228 to 0.23 μA⋅cm−2.


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