scholarly journals Chemical Composition and Corrosion Behavior of a-C:H/DLC Film-Coated Titanium Substrate in Simulated PEMFC Environment

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 820
Author(s):  
Beibei Han ◽  
Mengyuan Yan ◽  
Dongying Ju ◽  
Maorong Chai ◽  
Susumu Sato
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Metal Ion ◽  
Ion Beam ◽  
Titanium Substrate ◽  
Corrosion Current ◽  
Ion Concentration ◽  
Bipolar Plates ◽  
High Adhesion ◽  
Corrosion Behaviors

The amorphous hydrogenated (a-C:H) film-coated titanium, using different CH4/H2 and deposition times, was prepared by the ion beam deposition (IBD) method, which has the advantage of high adhesion because of the graded interface mixes at the atomic level. The chemical characterizations and corrosion behaviors of a-C:H film were investigated and evaluated by SEM, AFM, Raman spectroscopy, EPMA, TEM and XPS. An a-C:H film-coated titanium was corroded at 0.8 V, 90 °C in a 0.5 mol/L H2SO4 solution for 168 h. The metal ion concentration in the H2SO4 corrosion solution and the potentiodynamic polarization behavior were evaluated. Results indicate that a higher CH4/H2 of 1:0 and a deposition time of 12 h can result in a minimum ID/IG ratio of 0.827, Ra of 5.76 nm, metal ion concentration of 0.34 ppm in the corrosion solution and a corrosion current of 0.23 µA/cm2. The current density in this work meets the DOE’s 2020 target of 1 µA/cm2. Electrical conductivity is inversely proportional to the corrosion resistance. The significant improvement in the corrosion resistance of the a-C:H film was mainly attributed to the increased sp3 element and nanocrystalline TiC phase in the penetration layer. As a result, the a-C:H film-coated titanium at CH4/H2 = 1:0 with improved anti-corrosion behavior creates a great potential for PEMFC bipolar plates.

scholarly journals Corrosion Resistance of DLC Film-Coated SUS316L Steel Prepared by Ion Beam Enhanced Deposition

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Bei B. Han ◽  
Dong Y. Ju ◽  
Mao R. Chai ◽  
Hui J. Zhao ◽  
Susumu Sato
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Metal Ion ◽  
Ion Beam ◽  
Acid Corrosion ◽  
Electrochemical Techniques ◽  
Ion Concentration ◽  
Dlc Coatings ◽  
Dlc Film ◽  
Corrosion Behaviors

In order to improve the conductivity and anticorrosive resistance of bipolar plates in fuel cells, the characterizations and corrosion behaviors of the DLC-coated SUS316L steel deposited with different gas ratios CH4/H2 and deposition times were investigated and evaluated. The chemical bonding structure and composition of the DLC coatings were confirmed by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The micromorphology and surface roughness of the DLC were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The element compositions of cross section were determined by electron probe microanalysis (EPMA). The interfacial contact resistance (ICR) was measured. Furthermore, the DLC-coated SUS316L steel was corroded by potentiostatic polarizations in a 0.5 M H2SO4 solution at 0.8 V, 90°C for 168 h, and the corrosion behaviors were investigated in the solution using electrochemical techniques. In addition, the metal ions in sulfuric acid corrosion solution were detected by inductively coupled plasma-atomic emission spectroscopy. The results indicate that the DLC coatings deposited at a lower gas ratio CH4/H2 of 1 : 1 could result in a decreasing ID/IG ratio of 1.03, low Ra roughness of 3.77 nm, low ICR of 12.9 mΩ cm2, and low metal ion concentration of 16.60 ppm in the corrosion solution. The significant improvement in the anticorrosion resistance of the DLC film was mainly due to the increased sp3 element and formation of the passive film. As a result, the DLC coating deposited on the SUS316L steel at CH4/H2 = 1 : 1 has better anticorrosion properties. However, the DLC film-coated SUS316L steel still cannot meet the corrosive resistance of the bipolar plate.

Effect of High-Intensity Pulsed Ion Beam Irradiation on the Electrochemical Corrosion Behavior of AZ31 Magnesium Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 571-574
Author(s):  
Peng Li
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Current Density ◽  
Ion Beam ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Open Circuit ◽  
Electrochemical Corrosion Behavior ◽  
Shot Number

HIPIB irradiation experiment is carried out at a specific ion current density of 1.1 J/cm2 with shot number from one to ten in order to explore the effect of shot number on electrochemical corrosion behavior of magnesium alloy. Surface morphologies, microstructure and corrosion resistance of the irradiated samples are examined by scanning electron microscopy (SEM), transmission electron microscope (TEM) and potentiodynamic polarization technique, respectively. It is found that HIPIB irradiation leads to the increase in open circuit potential, corrosion potential and breakdown potential, and the decrease in the corrosion current density and the corrosion rate as compared to the original sample. The improved corrosion resistance is mainly attributed to the grain refinement and surface purification induced by HIPIB irradiation.

scholarly journals Corrosion Behavior and Osteogenic Activity of a Biodegradable Orthopedic Implant Mg–Si Alloy with a Gradient Structure

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 781
Author(s):  
Weiyan Jiang ◽  
Wenzhou Yu
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Polarization Resistance ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Gradient Structure ◽  
Orthopedic Implant ◽  
Biological Functions ◽  
Alloy Matrix ◽  
Osteogenic Activity

A gradient Mg-8 wt % Si alloy, which was composed of the agglomerated Mg2Si crystals coating (GMS8-1) and the eutectic Mg–Si alloy matrix (GMS8-2), was designed for biodegradable orthopedic implant materials. The bio-corrosion behavior was evaluated by the electrochemical measurements and the immersion tests. The results show that a significant improvement of bio-corrosion resistance was achieved by using the gradient Mg–Si alloy, as compared with the traditional Mg-8 wt % Si alloy (MS8), which should be attributed to the compact and insoluble Mg2Si phase distributed on the surface of the material. Especially, GMS8-1 exhibits the highest polarization resistance of 1610 Ω, the lowest corrosion current density of 1.7 × 10−6 A.cm−2, and the slowest corrosion rate of 0.10 mm/year. In addition, GMS8-1 and GMS8-2 show better osteogenic activity than MS8, with no cytotoxicity to MC3T3-E1 cells. This work provides a new way to design a gradient biodegradable Mg alloys with some certain biological functions.

PVD Coated Bipolar Plates for PEM Fuel Cells

2005 ◽  
Vol 2 (4) ◽  
pp. 290-294 ◽  
Author(s):  
Shuo-Jen Lee ◽  
Ching-Han Huang ◽  
Yu-Pang Chen ◽  
Chen-Te Hsu
Keyword(s):  
Corrosion Resistance ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Physical Vapor Deposition ◽  
Corrosion Current ◽  
Pem Fuel Cells ◽  
Bipolar Plates ◽  
Coating Materials ◽  
Pvd Coating ◽  
Simulated Fuel

Aluminum was considered a good candidate material for bipolar plates of the polymer electrolyte membrane (PEM) fuel cells due to its low cost, light weight, high strength and good manufacturability. But there were problems of both chemical and electrochemical corrosions in the PEM fuel cell operating environment. The major goals of this research are to find proper physical vapor deposition (PVD) coating materials which would enhance surface properties by making significant improvements on corrosion resistance and electrical conductivity at a reasonable cost. Several coating materials had been studied to analyze their corrosion resistance improvement. The corrosion rates of all materials were tested in a simulated fuel cell environment. The linear polarization curve of electrochemical method measured by potentiostat instrument was employed to determine the corrosion current. Results of the corrosion tests indicated that all of the coating materials had good corrosion resistance and were stable in the simulated fuel cell environment. The conductivities of the coated layers were better and the resistances changed very little after the corrosion test. At last, single fuel cells were made by each PVD coating material. Fuel cell tests were conducted to determine their performance w.r.t. that was made of graphite. The results of fuel cell tests indicated that metallic bipolar plates with PVD coating could be used in PEM fuel cells.

Effects of potassium silicate on corrosion behavior of dacromet coating

2019 ◽  
Vol 66 (6) ◽  
pp. 819-826
Author(s):  
Khashayar Tabi ◽  
Mansour Farzam ◽  
Davood Zaarei
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Automobile Industry ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Corrosion Current ◽  
Potassium Silicate ◽  
Coated Steel ◽  
Content Type ◽  
New Information

Purpose Potassium silicate sealer was applied on solvent-cleaned, acid-pickled, dacromet-coated steel to improve its corrosion resistance. The purpose of this paper is to study the corrosion behavior of dacromet-coated steel. Design/methodology/approach Potassium silicate sealer was applied on solvent-cleaned, acid-pickled, dacromet-coated steel to improve its corrosion resistance. Electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and salt spray were carried out. SEM was used to study the morphological appearance of the surface. Findings The EIS behavior indicated that solvent-cleaned dacromet-coated steel sealed with potassium silicate showed that the corrosion current density was 2.664E − 5 A.cm2 which was reduced to 8.752E − 6 A.cm2 and the corrosion rate, which was 2.264E − 2 mm.year−1, was reduced to 7.438E − 3 mm.year−1 in NaCl 3.5 wt.per cent. EIS was used in NaCl 3.5 wt.%, and the Bode plot characteristics showed that the corrosion protection of solvent-cleaned, dacromet-coated steel was enhanced when sealed with potassium silicate. The EDS results of salt-sprayed, solvent-cleaned samples after 10 days indicated that the main corrosion products are composed of SiO2, ZnO and Al2O3. Research limitations/implications The detection of Li element in EDS was not possible because of the device limitation. Originality/value The current paper provides new information about the sealing properties of potassium silicate and its effects on the corrosion resistance of dacromet coating, which is widely used in many industries such as the automobile industry.

Effect of ECAP Pass on Corrosion Behavior of High-Al Content Magnesium Alloys

2013 ◽  
Vol 747-748 ◽  
pp. 270-275
Author(s):  
Qiang Fan ◽  
Wei Liang ◽  
Li Ping Bian ◽  
Man Qing Cheng
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Performance Test ◽  
Corrosion Current ◽  
Second Phase ◽  
Al Content ◽  
Microstructure Observation ◽  
Angular Pressing ◽  
The Matrix ◽  
High Al Content

In view of low strength and poor corrosion resistance of Mg alloys, a Mg-12Al-0.7Si alloy was designed, fabricated and subjected to equal channel angular pressing (ECAP) in order to refine the microstructure. Microstructure observation and electrochemical performance test were conducted to investigate the influence of the microstructural variation subjected to multi-pass ECAP processing on the corrosion behavior of the alloy. The results showed that both α-Mg matrix and β-Mg17Al12of the alloy were significantly refined after processing for different passes (2,4,6,8) through route BC, and the 4-pass ECAPed alloy in 3.5% NaCl solution presents the lowest weight loss, lower corrosion current and higher corrosion potential in the polarization curves. The reason for high corrosion resistance of 4-pass ECAPed alloy and the effects of grain size of the matrix and the particle size, distribution of second phase and dynamic precipitates on corrosion behavior of the alloy were discussed.

Influence of EDTA-2Na Concertration on the Microstructure and Corrosion Behaviors of Mg-Al-Y Alloy

2015 ◽  
Vol 727-728 ◽  
pp. 201-204
Author(s):  
Yun Long Zhang ◽  
Mu Qin Li ◽  
Ping Liao ◽  
Yu Min Zhang
Keyword(s):  
Corrosion Resistance ◽  
Electrolyte Solution ◽  
Oxidation Process ◽  
Corrosion Current ◽  
Positive Potential ◽  
Micro Arc Oxidation ◽  
Corrosion Behaviors ◽  
Oxidation Technology ◽  
Structural Surface ◽  
Polarisation Measurements

In this paper,the micro-arc oxidation technology were utilized to fabricated the oxidation coating in order to resolve the corrosion resistance of the Mg-Al-Y alloy. The EDTA-2Na solution was introduced into the electrolyte solution for improving the coating corrosion properties.After the micro-arc oxidation process, phase structural, surface morphology and corrosion resistance of the MAO coating of Mg-Al-Y alloy were performed by XRD, SEM and Potentiodynamic polarisation measurements. The introduce of EDTA-2Na in the electrolyte solution improve the positive potential and reduced the corrosion current, which would improve the corrosion resistance properties of the Mg-Al-Y alloy.

Corrosion Behavior of Sm-Based Bulk Metallic Glasses in Salt Solution

2012 ◽  
Vol 229-231 ◽  
pp. 26-30
Author(s):  
Lin Bo Li ◽  
Jing Guo ◽  
Fei Peng Lou
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Salt Solution ◽  
Metallic Glasses ◽  
Glassy State ◽  
Bulk Metallic Glasses ◽  
Immersion Test ◽  
Comparison Study ◽  
Corrosion Behaviors

In this paper, the corrosion behaviors of Sm-based bulk metallic glasses (BMGs) were investigated by immersion test. It was found that with Co content increasing the ability of corrosion resistance of the alloy increases for Sm-based bulk metallic glasses. A comparison study was made on the corrosion behaviors between the glassy state alloys and crystalline alloys with the same ingredients. The results show that the glassy state alloy has the better corrosion resistance.

Effect of Fluoride on the Corrosion Behavior of Ti and Ti6Al4V Dental Implants Coupled With Different Superstructures

2011 ◽  
Vol 37 (3) ◽  
pp. 309-317 ◽  
Author(s):  
Eman M Anwar ◽  
Lamia S Kheiralla ◽  
Riham H Tammam
Keyword(s):  
Corrosion Resistance ◽  
Dental Implants ◽  
Corrosion Behavior ◽  
Artificial Saliva ◽  
Fluoride Concentration ◽  
Ion Concentration ◽  
Fluoride Ion ◽  
All Ceramic ◽  
Metal Ceramic ◽  
Implant Alloys

Abstract The effect of fluoride ion concentration on the corrosion behavior of Ti and Ti6Al4V implant alloys, when coupled with either metal/ceramic or all-ceramic superstructure, was examined by different electrochemical methods in artificial saliva solutions. It was concluded that increased fluoride concentration leads to a decrease in the corrosion resistance of all tested couples. The type of the superstructure also showed a significant effect on the corrosion resistance of the couple.

The combined erosion and corrosion resistance of WC-Ni vacuum brazed coating

2017 ◽  
Vol 64 (6) ◽  
pp. 626-633 ◽  
Author(s):  
Hyung Goun Joo ◽  
Kang Yong Lee ◽  
Guo Ming Luo ◽  
Da Quan Zhang
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Coating Layer ◽  
Diffusion Coating ◽  
Test Time ◽  
Content Type ◽  
X Ray ◽  
Combined Test ◽  
Material Erosion ◽  
Corrosion Behaviors

Purpose The purpose of this paper is to investigate the combined erosion and corrosion behavior of WC-Ni vacuum brazed coating. Design/methodology/approach Al2O3 particles and 10 wt% NaCl solution are used to evaluate erosion and corrosion resistance of WC-Ni vacuum brazed coating. Combined test of erosion and corrosion is also conducted. The microstructure of each specimen is characterized by the scanning electron microscopy. The chemical composition was determined by energy-dispersive X-ray spectroscopy. Findings WC-Ni vacuum brazed coating layer is effective protective coating under combined erosion and corrosion environment. The weight loss of coating layer is more reduced as the cumulative test time. Originality/value WC-Ni vacuum brazed coatings are investigated to check characteristic of the combined erosion and corrosion environment. WC-Ni vacuum brazed coatings are kind of diffusion coating that attract attention because of the resistance of superb impact and corrosion in comparison with other coatings. Some previous researches reported the properties of vacuum brazed WC material. Erosion and corrosion behaviors of WC-Ni vacuum brazed coatings were studied in our previous research, respectively. Hence, in this research, the principal objective is to examine the combined erosion and corrosion behavior of WC-Ni vacuum brazed coating.

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