scholarly journals Epoxy coatings electrodeposited on aluminium and modified aluminium surfaces

2002 ◽  
Vol 56 (11) ◽  
pp. 468-472
Author(s):  
Zorica Lazarevic ◽  
Vesna Miskovic-Stankovic ◽  
Zorica Kacarevic-Popovic ◽  
Dragutin Drazic
Keyword(s):  
Thermal Stability ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
The Other ◽  
Nacl Solution ◽  
H2 Evolution ◽  
Epoxy Coatings ◽  
Protective Properties ◽  
Aluminum Surfaces ◽  
Thermal Stability Of

The corrosion behaviour and thermal stability of epoxy coatings electrodeposited on modified aluminum surfaces (anodized, phosphatized and chromatized-phosphatized aluminium) were monitored during exposure to 3% NaCl solution, using electrochemical impedance spectroscopy (EIS) and thermogravimetric analysis (TGA). Better protective properties of the epoxy coatings on anodized and chromatized-phosphatized aluminum with respect to the same epoxy coatings on aluminum and phosphatized aluminum were obtained: higher values of Rp and Rct and smaller values of Cc and Cd, from EIS, and a smaller amount of absorbed water inside the coating, from TGA. On the other hand, a somewhat lower thermal stability of these coatings was obtained (smaller values of the ipdt temperature). This behavior can be explained by the less porous structure of epoxy coatings on anodized and chromatized-phosphatized aluminum, caused by a lower rate of H2 evolution and better wet ability.

scholarly journals Electrochemical properties and thermal stability of epoxy coatings electrodeposited on aluminium and modified aluminium surfaces

2001 ◽  
Vol 66 (11-12) ◽  
pp. 871-880 ◽  
Author(s):  
Vesna Miskovic-Stankovic ◽  
Zorica Lazarevic ◽  
Zorica Kacarevic-Popovic
Keyword(s):  
Thermal Stability ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Charge Transfer Resistance ◽  
Epoxy Coatings ◽  
Transfer Resistance ◽  
Protective Properties ◽  
Chemically Modified ◽  
Thermal Stability Of

The corrosion behaviour of epoxy coatings electrodeposited on aluminium, as well as on electrochemically and chemically modified aluminium were investigated during exposure to 3 % NaCl. Electrochemical impedance spectroscopy (EIS) and thermogravimetric analysis (TGA) were used for the determination of the protective properties of epoxy coatings on aluminium, anodized aluminium, phosphatized and chromatized-phosphatized aluminium. The protective properties of epoxy coatings on anodized and chromatized-phosphatized aluminium are significantly improved with respect to the same epoxy coatings on aluminium and phosphatized aluminium: higher values of the pore resitance and charge-transfer resistance, lower values of the coating capacitance, double-layer capacitance and relative permittivity (from EIS) smaller amount of absorbed water inside the coating (From TGA). On the other hand, the lower values of the ipdt temperature indicate a lower thermal stability of the epoxy coatings on anodized and chromatized-phosphatized aluminium.

scholarly journals The effect of Zn-Ni sublayers on the corrosion behaviour and thermal stability of epoxy coatings electrodeposited on steel

2000 ◽  
Vol 65 (12) ◽  
pp. 923-933 ◽  
Author(s):  
Vesna Miskovic-Stankovic ◽  
Jelena Bajat ◽  
Miodrag Maksimovic ◽  
Zorica Kacarevic-Popovic
Keyword(s):  
Thermal Stability ◽  
Pulse Current ◽  
Corrosion Behaviour ◽  
Epoxy Coating ◽  
Epoxy Coatings ◽  
Corrosion Stability ◽  
Ni Alloys ◽  
Protective System ◽  
Thermal Stability Of ◽  
Protective Systems

The electrochemical and transport properties, as well as the thermal stability of epoxy coatings electrodeposited on steel and steel modified by Zn-Ni alloys were investigated during exposure to 3% NaCl. The Zn-Ni alloys were electrodeposited on steel using direct and pulse current. From the time dependence of the pore resistance of the epoxy coating (impedance measurements), the diffusion coefficient of water through the epoxy coating (gravimetric liquid sorption measurements) and the thermal stability of the epoxy coating (thermogravimetric analysis), it was shown that Zn-Ni sublayers significantly improve the corrosion stability of a protective system based on an epoxy coating. The values of the pore resistance were almost unchanged over a long period of immersion time for epoxy coatings on steel modified by Zn-Ni alloys, inidicating the great stability of these protective systems.

Toxic properties of Aeromonas proteolytica

1974 ◽  
Vol 20 (10) ◽  
pp. 1403-1409 ◽  
Author(s):  
B. G. Foster ◽  
Mary O. Hanna
Keyword(s):  
Thermal Stability ◽  
Culture Filtrate ◽  
Hemolytic Activity ◽  
Optimal Growth ◽  
Growth Conditions ◽  
The Other ◽  
Activity Peak ◽  
Endopeptidase Activity ◽  
Time Periods ◽  
Thermal Stability Of

Aeromonas proteolytica was grown for various time periods in nutrient broth, tryptic soy broth, a semisynthetic medium, and 1 and 5% peptone under different conditions involving temperature and in continuous shake and stationary flasks. The cell-free culture filtrates were tested for hemolytic, endopeptidase, and dermonecrotic activity and optimal growth conditions for their production were determined. The dermonecrotic activity and endopeptidase activity was found to be parallel in all tests, while hemolysin was independent of the other two. Studies on the thermal stability of the culture filtrate revealed that hemolysin and dermonecrotic and endopeptidase activity were destroyed at 70 °C for 30 min. Fractionation of the filtrate by Sephadex G-200 resolved three peaks at 280 nm. Peak I was inactive; peak II contained endopeptidase and dermonecrotic and hemolytic activity; peak III contained pigment and hemolysin. Evidence is presented that the endopeptidase and dermonecrotic substance found in the cell-free filtrates of A. proteolytica grown medium appear at the same time and thus may be the same entity.

scholarly journals Corrosion of the Welded Aluminium Alloy in 0.5 M NaCl Solution. Part 2: Coating Protection

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2177 ◽  
Author(s):  
Andrey Gnedenkov ◽  
Sergey Sinebryukhov ◽  
Dmitry Mashtalyar ◽  
Igor Vyaliy ◽  
Vladimir Egorkin ◽  
...  
Keyword(s):  
Aluminium Alloy ◽  
Welded Joint ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Weld Interface ◽  
Open Circuit ◽  
Al Alloy ◽  
Protective Properties ◽  
Coating Formation ◽  
Electrode Technique

The high electrochemical activity of the aircraft 1579 aluminium alloy with a welded joint and the necessity of the coating formation to protect this material against corrosion as well as to increase the stability of the weld interface in the corrosive medium has been previously established. In this work, two suggested methods of protective coating formation based on plasma electrolytic oxidation (PEO) in tartrate-fluoride electrolyte significantly increased the protective properties of the welded joint area of the 1579 Al alloy. The electrochemical properties of the formed surface layers have been investigated using SVET (scanning vibrating electrode technique) and SIET (scanning ion-selective electrode technique), EIS (electrochemical impedance spectroscopy), OCP (open circuit potential), and PDP (potentiodynamic polarization) in 0.5 M NaCl. The less expressed character of the local electrochemical processes on the welded 1579 Al alloy with the composite coating in comparison with the base PEO-layer has been established. Polymer-containing coatings obtained using superdispersed polytetrafluoroethylene (SPTFE) treatment are characterized by the best possible protective properties and prevent the material from corrosion destruction. Single SPTFE treatment enables one to increase PEO-layer protection by 5.5 times. The results of this study indicate that SVET and SIET are promising to characterize and to compare corrosion behaviour of coated and uncoated samples with a welded joint in chloride-containing media.

Dependence of Vickers Hardness on Annealing Temperature at Co/Cu Multilayered Films

2007 ◽  
Vol 561-565 ◽  
pp. 2399-2402
Author(s):  
Yoshihisa Kaneko ◽  
H. Sakakibara ◽  
Satoshi Hashimoto
Keyword(s):  
Thermal Stability ◽  
Vickers Hardness ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Copper Substrate ◽  
The Other ◽  
Multilayered Structures ◽  
Multilayered Films ◽  
Hardness Tests ◽  
Thermal Stability Of

Co/Cu and Ni/Cu multilayers fabricated by electroplating technique were annealed at various temperatures in order to investigate thermal stability of multilayered structures. Vickers hardness tests on the annealed Co/Cu and Ni/Cu multilayers were conducted at room temperature. It was recognized that after the annealing at 1023K the Co/Cu multilayer still maintained the hardness of as-deposited state. On the other hand, the hardness of Ni/Cu multilayer was almost identical to copper substrate after the annealing at 903K.

Effect of Different Dopants in Films TEOS/MPTS Used to Protect the Carbon Steel

2014 ◽  
Vol 805 ◽  
pp. 167-171 ◽  
Author(s):  
F.S. Silva ◽  
P.H. Suegama ◽  
W.P. Silva ◽  
A.W. Rinaldi ◽  
N.L.C. Domingues ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Open Circuit Potential ◽  
Hybrid Film ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
The Other ◽  
Nacl Solution ◽  
Hybrid Films ◽  
Impedance Measurements ◽  
Current Densities

Schiff bases m-toluene N-Salicylideneaniline (m-TOL), (B) m-nitro-N- Salicylideneaniline (m-NTR) and (C) m-methoxy-N-salicylideneaniline (m-MTX) and cerium ions were studied added to 3.5 wt.% NaCl solution and added to the hybrid film based tetraethoxysilane (TEOS) e 3-methacryloxypropyltrimethoxysilane (MPTS). The polarization measurements showed lower current densities for the steel in NaCl with m-MTX, indicating that the m-MTX may be acting as an inhibitor. The hybrid films were doped with the m-MTX, Ce (III) or Ce (IV). Electrochemical measurements of open circuit potential (EOC), polarization curves and electrochemical impedance spectroscopy (EIS), were used to evaluate the corrosion behavior of the hybrid films. According Electrochemical Impedance measurements, all hybrid films, provided protection to the carbon steel. The films doped with Ce (IV), provided greater protection than the other, which indicates that this is the most suitable dopant for use in films.

Sputtered Cu Films Containing Various Insoluble Substances for Advanced Barrierless Metallization

2007 ◽  
Vol 539-543 ◽  
pp. 3497-3502 ◽  
Author(s):  
J.P. Chu ◽  
C.H. Lin
Keyword(s):  
Thermal Stability ◽  
Leakage Current ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
The Other ◽  
Oxide Semiconductor ◽  
Good Thermal Stability ◽  
Cu Films ◽  
Pure Cu ◽  
Thermal Stability Of

Sputtered Cu films containing various insoluble substances, such as Cu(W2.3), Cu(Mo2.0), Cu(Nb0.4), Cu(C2.1) and Cu(W0.4C0.7), are examined in this study. These films are prepared by magnetron sputtering, followed by thermal annealing. The crystal structure, microstructure, SIMS depth-profiles, leakage current, and resistivity of the films are investigated. Good thermal stability of these Cu films is confirmed with focused ion beam, X-ray diffractometry, SIMS, and electrical property measurements. After annealing at 400°C, obvious drops in resistivity, to ~3.8 μ-cm, are seen for Cu(W) film, which is lower than the other films. An evaluation of the leakage current characteristic from the SiO2/Si metal-oxide-semiconductor (MOS) structure also demonstrates that Cu with dilute tungsten is more stable than the other films studied. These results further indicate that the Cu(W) film has more thermal stability than the Cu(Mo), Cu(Nb), Cu(C), Cu(WC) and pure Cu films. Therefore, the film is suitable for the future barrierless metallization.

Thermal Stability of Rapidly Quenched TI-NI-AL Amorphous Alloys

1985 ◽  
Vol 58 ◽  
Author(s):  
K. Aoki ◽  
K. Hiraga ◽  
T. Masumoto
Keyword(s):  
Thermal Stability ◽  
Amorphous Phase ◽  
Amorphous Alloys ◽  
Melt Spinning ◽  
Composition Range ◽  
Amorphous Matrix ◽  
Al Alloys ◽  
The Other ◽  
Molten State ◽  
Thermal Stability Of

ABSTRACTTi-Ni-Al alloys were rapidly quenched from a molten state by the melt spinning method. Three kinds of metastable phases, namely, amorphous,nonequilibrium and quasicrystalline phases are formed in these alloys. The amorphous phase is formed in the range of 35 to 70 at% Ti and 0 to 25 at% Al. The nonequilibrium phases are formed in the composition range of 25 to 33 at% Ti. On the other hand, fine quasicrystalline phases are distributed in the amorphous matrix of the Ti-rich alloys. Crystallization temperatures and the hardness of the amorphous alloys were also examined.

scholarly journals Temperature Dependence of the Pore Structure in Polyvinylidene Fluoride (PVDF)/Graphene Composite Membrane Probed by Electrochemical Impedance Spectroscopy

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1123 ◽  
Author(s):  
Qizhao Luo ◽  
Qing Huang ◽  
Zhe Chen ◽  
Lei Yao ◽  
Qiuming Fu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Pore Structure ◽  
Temperature Dependence ◽  
Composite Membrane ◽  
Electrochemical Impedance ◽  
Composite Membranes ◽  
Graphene Composite ◽  
Thermal Stability Of

In this paper, graphene was introduced in the PVDF to improve the thermal stability of the pore structure, which is the key feature for the membrane applied for the thermo-osmotic energy conversion (TOEC) process. The PVDF/graphene composite membranes were characterized by a scanning electron microscopy (SEM), a water contact angle measurement, and electrochemical impedance spectroscopy (EIS). It was found that the composite membranes exhibited improved surface hydrophobicity. Moreover, the pores in pure PVDF membrane would expand during the heat process while the existence of graphene in PVDF clearly suppressed the expansion, which implied better thermal stability of the pores in the composite membrane. According to the pore deformation time, the heat conductivities of the membranes were calculated and compared with each other. It confirmed that the composite membrane with higher graphene content exhibited enhanced heat conductivity. EIS can be used to monitor the temperature dependence of the pore structure in aqueous environments.

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