Effects on Corrosion Resistance of Ce-Sealed Ni-P Coatings with Ni-Low P and Ni-Medium P

2012 ◽  
Vol 472-475 ◽  
pp. 151-156
Author(s):  
Chun Yu Wang ◽  
Huan Ran Li ◽  
Wei Zhang ◽  
Yang Yu ◽  
Guang Wu Wen
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Inhibitor ◽  
Corrosion Potential ◽  
Surface Effects ◽  
Corrosion Current ◽  
Sem Analysis ◽  
Polarization Curves ◽  
Micro Cracks ◽  
P Content ◽  
Xrd Patterns

The post-treatment with Ce-rich sealing of Ni-P coating (Ce-sealed Ni-P coating) was developed on Al surface. Effects of corrosion resistance with different phosphorus contents in the Ni-P coatings were investigated in this paper. The results of the polarization curves show that the Ce-sealed Ni-(10wt.%)P coatings have the higher corrosion potential (Ecorr) and the lower corrosion current (icorr), indicating that this coating iSubscript texts a better corrosion inhibitor than Ni-(3wt.%)P coating. These results demonstrate that the P content plays an obvious role on improving the corrosion resistance of Ni-P coatings. It is results of SEM analysis shows that the Ce-sealed Ni-(3wt.%)P coating has not obvious micro-cracks, the Ce-sealed Ni-(10wt.%)P surface with some micro-cracks are appeared on Ce-rich coating. But this micro-cracks phenomenon of Ce-rich coating can not effect on corrosion resistance. Otherwise, there are no peaks of Ce-riched coatings in both XRD patterns, because too less Ce elements and non-crystal tendency is more serious on these coatings.

Effect of Diethylamine Addition on the Sealing Process of 6063 Al Alloy

2012 ◽  
Vol 557-559 ◽  
pp. 1857-1860
Author(s):  
Hui Cheng Yu ◽  
Xiao Xiao Huang ◽  
Yi Chun Wei ◽  
Dong Ping Wei
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Polarization Curves ◽  
Al Alloy ◽  
Electrochemical Tests ◽  
Electrochemical Parameters ◽  
6063 Al Alloy

To improve the corrosion resistance of Al alloy, diethylamine (DEA) was added into the sealing solutions. The electrochemical behavior of sealing coatings formed in different concentrations of diethylamine (DEA) was investigated by means of polarization curves and electrochemical impedance spectroscopy (EIS). Compared with the coatings with D. I. water and the bare aluminum alloy, the polarization curves show that the sealing coatings formed in 3.0 – 5.0 ml.L-1 diethylamine (DEA) solutions have more positive corrosion potential (Ecorr) and pitting corrosion potential (Epit), and lower corrosion current density (icorr). Electrochemical parameters of EIS indicate that the sealing coatings have higher corrosion resistance. The electrochemical tests present that the prepared sealing coatings have better corrosion resistance.

Protective behavior of volatile corrosion inhibitor on atmospheric corrosion process of carbon steel under thin electrolyte liquid film of chloride solutions

2020 ◽  
Vol 10 (9) ◽  
pp. 1435-1443
Author(s):  
Dong Wang ◽  
Chenxi Wang ◽  
Changqing Fang ◽  
Xing Zhou ◽  
Mengyuan Pu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Carbon Steel ◽  
Liquid Film ◽  
Corrosion Inhibitor ◽  
Current Density ◽  
Atmospheric Corrosion ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Corrosion Process ◽  
Closed Container

The corrosion process of carbon steel and corrosion resistance behavior of volatile corrosion inhibitor (VCI) under thin electrolyte liquid film containing chloride was investigated by electrochemical measurements and surface characterization. Results indicated that composite VCI was composed of sodium molybdate and sodium benzoate, and exhibited higher corrosion resistance in 3.5% NaCl solution compared with absence of VCI. The corrosion current density obviously decreased with presence of VCI, and the synergies between binary components increased the corrosion inhibiting rate on carbon steel to up to 90%. The corrosion current density of carbon steel increased with increased temperature after volatilization of VCI. A closed container was carried out to mimic atmospheric corrosion condition, and its vapor corrosion inhibition property was evaluated in this closed container. Results showed that the VCI acted as an inhibitor by suppressing anodic dissolution and metallic ion transfer through the formation of protective film. It was also observed that the variation of carbon steel surface with volatilization of VCI was assessed by atomic force microscope (AFM) and scanning electron microscope (SEM). The anodic process for carbon steel without VCI affected the corrosion rate due to accumulation of corrosion products, while the morphology of carbon steel was hardly changed with volatilization of VCI. The results showed that the VCI volatilized to the surface and form to protect film. VCI was automatically volatilized into gas, which protected steel from corrosion. This composite VCI can then be applied as a significant corrosion inhibition method.

Study on Structure and Properties of Ti/Pb-PANI-WC Inert Anodes

2012 ◽  
Vol 487 ◽  
pp. 53-57
Author(s):  
Mei Cao ◽  
Zhong Cheng Guo ◽  
Xiang Lan Xie ◽  
Su Qiong He
Keyword(s):  
Oxygen Evolution ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Electrode Reaction ◽  
Polarization Curves ◽  
Pulse Electrodeposition ◽  
Tafel Polarization ◽  
Inert Anodes ◽  
Conductive Polyaniline ◽  
Surface Morphologies

Pb-PANI-WC inert anodes were prepared by direct current and pulse electrodeposition of PANI (conductive polyaniline) and WC particles with Pb2+ on the surface of titanium (Ti) substrate. The anodic polarization curves, cyclic voltammetry curves and Tafel polarization curves were measured in the solution of 50 g/L Zn2+, 150 g/L H2SO4 and 35°C, and the kinetic parameters of oxygen evolution, voltammetry charge, corrosion potential and corrosion current density have been obtained. The surface morphologies of the coating were investigated by using scanning electron microscope(SEM).The results show that the inert anodes prepared by pulse electrodeposition possess lower overpotential of oxygen evolution, higher electrocatalytic activity, and better reversibility of electrode reaction and corrosion resistance.

Influence of SiC Content and Heat Treatment on the Corrosion Resis-Tance and Oxidation Resistance of Ni-P-SiC Composite Coating

2015 ◽  
Vol 817 ◽  
pp. 479-483
Author(s):  
Pan Li ◽  
Wan Chang Sun ◽  
Jun Gao ◽  
Quan Zhou ◽  
Pei Zhang
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Composite Coating ◽  
Oxidation Resistance ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Treatment Temperature ◽  
Micro Hardness ◽  
Resis Tance ◽  
P Matrix

Ni-P alloy and SiC micron particles were codeposited on Q235 steel by electroless plating. The composition, microstructure, micro-hardness, corrosion resistance and oxidation resistance of the composite coating were studied. The results revealed that the deposited composite coating shows dispersed SiC particles and continuous Ni-P matrix. When the content of SiC was 8g/L and the heat treatment temperature was 300°C, the corrosion potential and corrosion current of Ni-P-SiC coating were-0.292V, and 8.2×10-7 A/cm2, respectively, while those of Ni-P composite coating were-0.501V, and 4.2×10-5 A/cm2, respectively. Ni-P-SiC composite coating with high content of SiC exhibits better oxidation resistance than Ni-P coating.

scholarly journals Experimental evaluation of corrosion resistance of the alloys used in the fixed dental prosthesis

2015 ◽  
Vol 61 (2) ◽  
pp. 117-120
Author(s):  
Costin Coman ◽  
◽  
Raluca Monica Comăneanu ◽  
Violeta Hâncu ◽  
Horia Mihail Barbu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Current Density ◽  
Applied Research ◽  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Artificial Saliva ◽  
Corrosion Current ◽  
Open Circuit ◽  
Metal Alloys ◽  
Fixed Dental Prosthesis

Objectives. In this study we evaluated corrosion resistance of three types of metal alloys (two NiCr and one CoCr). Methods. Samples (coded A, B, C) of circular shape, with dimensions 13 x 1.5 mm, sanded and polished, were introduced in Fusayama Meyer artificial saliva at pH 5.2 and 37 ± 0.5°C and tested in terms of corrosion resistance with a potentiostat/galvanostat (model 4000 PARSTAT, Princeton Applied Research). Results. Open circuit potential EOC [mV] ranged between 21.316 and 5.75. Corrosion potential Ecor [mV] was between -73.536 and -395.662, and the corrosion current density icor [A/cm2] was between 1.237 x 10-6 and 905.13 x 10-9. Conclusion. The best corrosion behavior in Fusayama Meyer artificial saliva at pH 5.2 and at a temperature of 37 ± 0.5°C is the alloy A, followed by the alloy C.

scholarly journals Corrosion Resistance of Electrochemically Synthesized Modified Zaccagnaite LDH-Type Films on Steel Substrates

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7389
Author(s):  
Michael Kahl ◽  
Teresa D. Golden
Keyword(s):  
Corrosion Resistance ◽  
Layered Double Hydroxide ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
X Ray Diffraction ◽  
X Ray ◽  
Double Hydroxide ◽  
Double Hydroxides ◽  
Steel Substrates ◽  
Deposited Films

Modified zaccagnaite layered double hydroxide (LDH) type films were synthesized on steel substrates by pulsed electrochemical deposition from aqueous solutions. The resulting films were characterized by X-ray diffraction, scanning electron microscopy/X-ray dispersive spectroscopy, and Fourier transform infrared spectroscopy. Structural characterization indicated a pure layered double hydroxide phase; however, elemental analysis revealed that the surface of the films contained Zn:Al ratios outside the typical ranges of layered double hydroxides. Layer thickness for the deposited films ranged from approximately 0.4 to 3.0 μm. The corrosion resistance of the film was determined using potentiodynamic polarization experiments in 3.5 wt.% NaCl solution. The corrosion current density for the coatings was reduced by 82% and the corrosion potential was shifted 126 mV more positive when 5 layers of modified LDH coatings were deposited onto the steel substrates. A mechanism was proposed for the corroding reactions at the coating.

scholarly journals Corrosion Behavior of Corrosion-Resistant Spring Steel Used in High Speed Railway

2021 ◽  
Vol 11 (18) ◽  
pp. 8668
Author(s):  
Jinbo Li ◽  
Ziying Zhu ◽  
Hongwei Chen ◽  
Shaojie Li ◽  
Hongyan Wu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
High Speed ◽  
Corrosion Potential ◽  
Early Stage ◽  
Corrosion Current ◽  
Corrosion Products ◽  
Atmospheric Environment ◽  
Rust Layer ◽  
Experimental Steel

Corrosion behavior of 60Si2Mn-A and 60Si2Mn-B in simulated industrial atmospheric environment was investigated by alternate immersion corrosion test and electrochemical method. The phase, morphology, characteristics of corrosion products, and the distribution of Cr, Cu, and Ni in the corrosion products of experimental steel were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe microanalyzer (EPMA). The results show that the phase of rust layer is Fe3O4 and γ-FeOOH in the early stage and then changes to α-FeOOH and γ-FeOOH in the later stage; the size of the rust layer with corrosion resistance of 60Si2Mn is less than 60Si2Mn; the Cr element accumulates in the rust layer of the experimental steel in the early stage of corrosion resistance; and Cu, Ni, and Cr in the corrosion resistance 60Si2Mn are concentrated in the rust layer near the substrate In the later stage of corrosion. As the corrosion cycle is prolonged, the corrosion potential and the resistance of the rust layer of the experimental steel increases, and the corrosion current decreases; in the same corrosion cycle, the corrosion potential and corrosion resistance of 60Si2Mn-B are greater than 60Si2Mn, and the corrosion current is less than 60Si2Mn.

Characteristics of Inconel 625 Filler Metal Affecting to Weld and Deposited Metal Zones in the Case of Welded to Forged Steel for Piston Crown Material

2014 ◽  
Vol 1004-1005 ◽  
pp. 1114-1119
Author(s):  
Sung Yul Lee ◽  
Kyung Man Moon ◽  
Jong Pil Won ◽  
Jae Hyun Jeong ◽  
Tae Sil Baek
Keyword(s):  
Corrosion Resistance ◽  
Weld Metal ◽  
Base Metal ◽  
Anodic Polarization ◽  
Corrosion Potential ◽  
Filler Metal ◽  
Polarization Curves ◽  
Inconel 625 ◽  
Piston Crown ◽  
Deposited Metal

Recently, wear and corrosion of the engine parts surrounded with combustion chamber is more serious compared to the other parts of the engine due to using of heavy oil of low quality. Therefore, an optimum repair welding for these parts is very important to prolong their lifetime in a economical point of view. In this study, Inconel 625 filler metal was welded with GTAW method in the forged steel which would be generally used with piston crown material. In this case, the mechanical and corrosion properties between weld metal zone (WM) welded to the groove which were artificially made in the base metal and deposited metal zone (DM) only welded by Inconel 625 filler metal on the surface of the base metal were investigated using electrochemical methods, such as measurement of corrosion potential, anodic polarization curves, cyclic voltammogram and impedance etc. in 35% H2SO4 solution. The deposited metal zone exhibited a better corrosion resistance compared to the weld metal zone, furthermore, its corrosion potential was a nobler value rather than that of the weld metal zone. However, the hardness indicated more or less higher value in the weld metal zone. The corrosive products after measurement of anodic polarization curves was hardly observed both in the weld and deposited zones, while, the morphologies of the corroded surfaces exhibited general and pitting corrosion in the weld and deposited metal zones respectively. The fine pearlite microstructure was a little observed in the weld metal zone, moreover, the microstructure of ferrite with elliptical pattern was significantly increased in the deposited metal zone. As a result, it is considered that the amount of Cr, Mo and Ni having a high corrosion resistance diffuse and migrate from the weld metal zone to the base metal zone, thus, the deposited metal zone indicated a better corrosion resistance than the weld metal zone because the amount of Cr, Mo and Ni were much involved in deposited metal zone compared to the weld metal zone.

Difference of Corrosion Characteristics of the Welding Zone between Laser and TIG Welding

2010 ◽  
Vol 146-147 ◽  
pp. 899-903
Author(s):  
Kyung Man Moon ◽  
Yun Hae Kim ◽  
Myung Hoon Lee
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Laser Welding ◽  
Heat Exchangers ◽  
Intergranular Corrosion ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Tig Welding ◽  
Chromium Depletion ◽  
Welding Zone

Two kinds of welding methods were performed on 22APU stainless steel: laser welding and TIG welding. In this case, the differences of the corrosion characteristics of the welded zones between the two welding methods mentioned above were investigated with electrochemical methods such as the measurement of corrosion potential, polarization curves, cyclic voltammogram, etc. The Vickers hardness of all welded zones (WM:Weld Metal, HAZ:Heat-Affected Zone, BM:Base Metal) was relatively higher for the laser welding than for the TIG welding. Furthermore, the laser welding method’s corrosion current densities in all welding zones were also observed to have a lower value compared to TIG welding. In particular, the corrosion current density of BM, regardless of the welding method, was the lowest value among all other welding zones. Intergranular corrosion was not observed at the corroded surface of all laser-welded welding zones; however, it was observed at the TIG-welded WM and HAZ welding zones, which suggests that chromium depletion due to the formation of chromium carbide occurs on the WM and HAZ which are in the range of sensitization temperatures, therefore the zones can easily be corroded with a more active anode. Consequently, we can see that corrosion resistance of all welding zones of 22APU stainless steel may be improved by the use of laser welding. Keywords: Laser welding, TIG welding, Corrosion potential, Weld metal, Heat affected zone, Polarization curves, Chromium depletion1.Introduction In recent years, use of austenitic stainless steel, which has a high corrosion resistance, has been increasing due to the development of industries, such as atomic energy, aerospace, petro chemical, etc. When stainless steel was welded for numerous kinds of structures, intergranular corrosion would often be observed at the area surrounding the welding zone due to chromium depletion; in addition, there are numerous papers which have investigated both general corrosion and intergranular corrosion[1-6]. However, there are few experimental results on the effect of corrosion control at the welding zones when laser or TIG welding are used for the purpose of constructing heat exchangers with 22 APU stainless steel. Although laser welding is more expensive than TIG welding, laser welding is often used instead of TIG welding for the production of heat exchangers. Consequently, it has been suggested that, from a long-term point of view, laser welding is more economic than TIG welding. In this study, when TIG and laser welding are performed on the stainless steel, the differences of the corrosion characteristics in the welding zone was investigated with electrochemical methods. The experimental results are therefore expected to provide useful reference data for the appreciation of mechanical and corrosion characteristics in the welding zones.

Corrosion Resistance of Zn-Al-Mg Alloys with Hypoeutectic Microstructure

2019 ◽  
Vol 298 ◽  
pp. 52-58
Author(s):  
Guang Rui Jiang ◽  
Jian Zhou ◽  
Ting Shang ◽  
Guang Hui Liu
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Ternary Eutectic ◽  
Corrosion Current ◽  
Charge Transfer Resistance ◽  
Mg Alloys ◽  
Transfer Resistance ◽  
Warburg Impedance ◽  
Al Mg Alloys

Zn-Al-Mg alloys with hypoeutectic microstructure were melted through a high frequency induction furnace. The content of aluminum and magnesium in the alloys were between 1% to 2%. Scanning electron microscopy (SEM) was utilized to analyze microstructure and phase, respectively. Effect of alloying element contents on corrosion resistance was studied. Results show that the Zn-Al-Mg alloys are almost covered by primarily solidified Zn rich block phase and fine lamellar binary and ternary eutectic microstructure exist between the Zn rich phase. The corrosion resistance was characterized through electrochemical test which indicates that increasing Al and Mg content in the Zn-Al-Mg alloys decline corrosion current density. For alloys with 1% Al, more magnesium means lower corrosion potential. For alloys with 2% Al, however, more magnesium suggests higher corrosion potential. In Nyquist curves of electrochemical impedance spectroscopy (EIS) test, Warburg impedance portion could be found for all alloys. With increasing alloying elements content in the Zn-Al-Mg alloys, charge transfer resistance in higher frequency remarkably increase, which implies higher corrosion resistance.

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