Investigation on electrochemical behavior and surface conductivity of titanium carbide modified Ti bipolar plate of PEMFC

2020 ◽  
Vol 45 (16) ◽  
pp. 10050-10058 ◽  
Author(s):  
Jiefu Shi ◽  
Pengchao Zhang ◽  
Yuetong Han ◽  
Hongyu Wang ◽  
Xinyu Wang ◽  
...  
2019 ◽  
Vol 66 (4) ◽  
pp. 520-526
Author(s):  
Fupeng Cheng ◽  
Jinglong Cui ◽  
Shuai Xu ◽  
Hongyu Wang ◽  
Pengchao Zhang ◽  
...  

Purpose The purpose of this paper is to improve the surface electrical conductivity and corrosion resistance of AISI 430 stainless steel (430 SS) as bipolar plates for proton exchange membrane fuel cells (PEMFCs), a protective Nb-modified layer is formed onto stainless steel via the plasma surface diffusion alloying method. The effect of diffusion alloying time on electrochemical behavior and surface conductivity is evaluated. Design/methodology/approach In this work, the surface electrical conductivity and corrosion resistance of modified specimen are evaluated by the potentiodynamic and potentionstatic polarization tests. Moreover, the hydrophobicity is also investigated by contact angle measurement. Findings The Nb-modified 430 SS treated by 1.5 h (1.5Nb) presented a lower passivation current density, lower interfacial contact resistance and a higher hydrophobicity than other modified specimens. Moreover, the 1.5 Nb specimen presents a smoother surface than other modified specimens after potentionstatic polarization tests. Originality/value The effect of diffusion alloying time on electrochemical behavior, surface conductivity and hydrophobicity of modified specimen is evaluated. The probable anti-corrosion mechanism of Nb-modified specimen in simulated acid PEMFC cathode environment is presented.


Author(s):  
Heli Wang ◽  
Glenn Teeter ◽  
John A. Turner

Austenitic 349 stainless steel was nitrided in an NH3 plasma. A low interfacial contact resistance was obtained with the nitrided steel. Glancing angle X-ray diffraction suggests that the nitrided layer is very thin and possibly amorphous. X-ray photoelectron spectroscopy (XPS) studies show that the nitrided layer is composed of mixed oxides and nitrides of Fe3+ and Cr3+. Contaminations of V and Sn were also observed, though their influence on the as-nitrided surface conductivity is not clear. The nitrided samples were investigated in a simulated polymer electrolyte membrane fuel cell (PEMFC) environment, and showed excellent corrosion resistance. The XPS depth profile indicated that the passive film, which formed on the plasma-nitrided steel in the PEMFC anode environment, is composed of mixed oxides and nitrides, in which chromium oxide/nitride dominates the surface chemistry. No V or Sn was detected on the surface after the polarization tests. For the PEMFC bipolar plate application, nitridation in NH3 plasma is a promising surface treatment approach, though more research is needed to investigate the influence of the plasma density and substrate bias on the surface conductivity and performance of the nitrided steel in PEMFC environments.


e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Chen Shia-Chung ◽  
Shih Ming-Yi ◽  
Lin Yi-Chang

AbstractIn this study, PPS blended with as high as 50 wt% carbon fiber were injection molded. Effects of molding conditions as well as the melt flow condition parallel and perpendicular to fluid channel on the surface conductivity was investigated. It was found that mold temperature affects the surface conductivity of molded parts significantly. Using a variable mold temperature control system based on electromagnetic induction heating, the conductivity of the molded part increase by about 152% when the peak mold temperature increases from 120 °C to 210 °C. The channel layout also helps the fiber to orient more randomly leading to an increase in the conductivity. The channel design parallel to melt flow increases the conductivity by 152% and when it is perpendicular to melt flow, the conductivity increases by 95%. Channel layout perpendicular to melt flow direction provides more influence on the fiber reorientation than that of the parallel design.


2006 ◽  
Vol 51 (17) ◽  
pp. 3592-3598 ◽  
Author(s):  
R.F. Silva ◽  
D. Franchi ◽  
A. Leone ◽  
L. Pilloni ◽  
A. Masci ◽  
...  

2019 ◽  
Vol 66 (2) ◽  
pp. 222-229 ◽  
Author(s):  
Jixin Han ◽  
Haibang Zhang ◽  
Juncai Sun ◽  
Wenyuan Zhao ◽  
Jinlong Cui

Purpose The purpose of this study is to improve the surface electrical conductivity and corrosion resistance of AISI430 stainless steel (430 SS) as bipolar plates for direct formic acid fuel cell (DFAFC). Design/methodology/approach The niobium diffusion layers have been successfully synthesized on 430 SS substrate by the plasma surface diffusion alloying technique under different diffusion alloying time. Findings The surface morphology of Nb-modified 430 SS prepared under the diffusion alloying time of 2 h is more homogeneous, relatively sleek and compact without surface micropore and other common surface blemishes. The potentiostatic and potentiodynamic polarization measurements manifest that Nb-modified 430 SS prepared under the diffusion alloying time of 2 h enormously ameliorate the corrosion resistance of bare 430 SS compared with other Nb-modified 430 SS samples and its corrosion current density is maintained at −1.4 µA cm−2 in simulated anodic environment of DFAFC (0.05 M H2SO4 + 2 ppm HF + 10 M formic acid at 50 °C). Originality/value The effect of diffusion alloying time on the corrosion resistance and surface conductivity of Nb-modified 430 SS has been carefully studied. The Nb-modified 430 SS samples prepared at the diffusion alloying time of 2 h have the best surface electrical conductivity and corrosion resistance in the simulated anodic environment of DFAFC.


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