Photoelectrochemical analysis of passive films formed on Ni and its alloys and its application to their corrosion behaviors

2015 ◽  
Vol 19 (12) ◽  
pp. 3427-3438 ◽  
Author(s):  
HeeJin Jang ◽  
HyukSang Kwon
Keyword(s):  
Passive Films ◽  
Corrosion Behaviors ◽  
Ni And Its Alloys

scholarly journals Corrosion Behavior and Morphology of Passive Films Modified with Zinc–Aluminum Simultaneous Treatment on Different Metals

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 986
Author(s):  
Shenghan Zhang ◽  
Chenhao Sun ◽  
Jie Di ◽  
Yu Tan
Keyword(s):  
Energy Dispersive Spectrometry ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Passive Films ◽  
Composition Analysis ◽  
304L Stainless Steel ◽  
Simultaneous Treatment ◽  
Incoloy 800 ◽  
Corrosion Behaviors

Passive films were formed on A508-3 steel (A508-3), 304L stainless steel (304L) and Incoloy 800 (In800) with blank/zinc/zinc–aluminum treatments in air at 300 °C. The electrochemical corrosion behaviors of different metals were investigated through potentiodynamic polarization, electrochemical impedance spectroscopy and the Mott–Schottky technique. The morphology and composition of passive films were analyzed using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The zinc–aluminum treatment effectively reduced the corrosion current and increased the impedance of A508-3 and 304L, but had a weak effect on In800. The zinc–aluminum treatment reduced the carrier concentration of A508-3 and changed the semiconductor property of 304L and In800. The order of zinc–aluminum treatment for improving the corrosion resistance of three metals was: A508-3 > 304L > In800. In addition, the zinc–aluminum treatment enhanced the density and smoothness of passive films. According to the composition analysis, spinel ZnAl2O4 was formed on three metals; however, the amount of spinel varied with the content of nickel and chromium in different metals, which affected the results of using this technology.

scholarly journals Effect of Laser Power on Microstructure and Micro-Galvanic Corrosion Behavior of a 6061-T6 Aluminum Alloy Welding Joints

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 3
Author(s):  
Huiling Zhou ◽  
Fanglian Fu ◽  
Zhixin Dai ◽  
Yanxin Qiao ◽  
Jian Chen ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Laser Power ◽  
Galvanic Corrosion ◽  
Gas Metal Arc Welding ◽  
Immersion Test ◽  
Intermetallic Particles ◽  
Metal Arc Welding ◽  
Corrosion Behaviors ◽  
Welding Joints ◽  
Corrosion Pits

The 6061-T6 aluminum alloy welding joints were fabricated using gas metal arc welding (GMAW) of various laser powers, and the effect of laser power on the microstructure evolution of the welding joints was investigated. The corrosion behaviors of 6061-T6 aluminum alloy welding joints were investigated in 3.5 wt% NaCl solution using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results showed that the micro-galvanic corrosion initiation from Mg2Si or around the intermetallic particles (Al-Fe-Si) is observed after the immersion test due to the inhomogeneous nature of the microstructure. The preferential dissolution of the Mg2Si and Al-Fe-Si is believed to be the possible cause of pitting corrosion. When the laser power reached 5 kW, the microstructure of the welded joint mainly consisted of Al-Fe-Si rather than the Mg2Si at 2 kW. The relatively higher content of Al-Fe-Si with increasing in laser power would increase the volume of corrosion pits.

Microstructural characterizations and wear and corrosion behaviors of laser-nitrided NAK80 mold steel

2021 ◽  
Vol 410 ◽  
pp. 126956
Author(s):  
Won-Sang Shin ◽  
Ahjin Sim ◽  
Seungwoo Baek ◽  
Soo Jin Choi ◽  
Heeshin Kang ◽  
...  
Keyword(s):  
Wear And Corrosion ◽  
Corrosion Behaviors

scholarly journals Pitting Corrosion of Type 316L Stainless Steel Elaborated by the Selective Laser Melting Method: Influence of Microstructure

2021 ◽  
Author(s):  
V. Vignal ◽  
C. Voltz ◽  
S. Thiébaut ◽  
M. Demésy ◽  
O. Heintz ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
316L Stainless Steel ◽  
Electrochemical Impedance ◽  
Chemical Properties ◽  
Passive Films ◽  
First Order ◽  
Average Grain Size ◽  
Type 316L ◽  
Pure Matrix ◽  
Type 316L Stainless Steel

AbstractThe microstructure of two sets of 316L alloys (SLM and wrought structure) is determined using SPECTROMAXx stationary metal analyzer, FE-SEM/EDS and XRD. The physical–chemical properties of the passive films are also investigated by means of XPS, Auger after sputtering and electrochemical impedance spectroscopy measurements. Differences and similarities between the two sets of alloys are then identified. The corrosion behavior of alloys is investigated in NaCl solution at the macro- and microscale (microcapillary technique). It was found that the inclusion/particles cleanliness is the first-order parameter explaining differences between 316L(WS) and 316L(SLM). In the absence of particles (pure matrix), the two sets of alloys have the same corrosion behavior. Residual stresses, the average grain size, the PREN and the passive films properties are of second order.

scholarly journals Corrosion behaviors of 316 stainless steel and Inconel 625 alloy in chloride molten salts for solar energy storage

2020 ◽  
Vol 39 (1) ◽  
pp. 340-350
Author(s):  
Mingjing Wang ◽  
Song Zeng ◽  
Huihui Zhang ◽  
Ming Zhu ◽  
Chengxin Lei ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Molten Salt ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Inconel 625 ◽  
Transfer Resistance ◽  
316 Stainless Steel ◽  
Corrosion Rates ◽  
Inconel 625 Alloy ◽  
Corrosion Behaviors

AbstractCorrosion behaviors of 316 stainless steel (316 ss) and Inconel 625 alloy in molten NaCl–KCl–ZnCl2 at 700°C and 900°C were investigated by immersion tests and electrochemical methods, including potentiodynamic polarization and electrochemical impedance spectroscopy. X-ray diffraction and scanning electron microscopy/energy dispersive spectroscopy were used to analyze the phases and microstructures of the corrosion products. Inconel 625 alloy and 316 ss exhibited high corrosion rates in molten chlorides, and the corrosion rates of these two alloys accelerated when the temperature increased from 700°C to 900°C. The results of the electrochemical tests showed that both alloys exhibited active corrosion in chloride molten salt, and the current density of 316 ss in chloride molten salt at 700°C was 2.756 mA/cm−2, which is about three times the value for Inconel 625 alloy; and the values of the charge transfer resistance (Rt) for Inconel 625 were larger than those for 316 ss. The corrosion of these two alloys is owing to the preferred oxidation of Cr in chloride molten salt, and the corrosion layer was mainly ZnCr2O4 which was loose and porous and showed poor adherence to metal.

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