scholarly journals Effect of N+ Implantation on Surface Characteristics of 316L Stainless Steels for Bipolar Plate in PEMFC

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 604
Author(s):  
Yu-Sung Kim ◽  
Dae-Wook Kim ◽  
In-Sik Lee ◽  
Sungook Yoon ◽  
Daeil Kim ◽  
...  

Nitrogen was implanted into 316L stainless steel by plasma immersion ion implantation (PIII) for surface modification. Due to nitrogen implantation, the corrosion resistance and interfacial contact resistance (ICR) were improved compared to the bare 316L stainless steel. The improved corrosion resistance was attributed to the formation of the expanded austenite phase (γN). The phase formation was found to be closely related to the evolution of the (111) plane texture. The formation of γN is strongly related to applied bias voltages. When bias voltages were increased to 15 kV, the γN phase was partially decomposed due to the formation of excessive nitride, including the CrN phase. For the ICR, increased crystallite size is effective in reducing contact resistance, which might arise from a reduced number of the grain boundary with electron scattering. In particular, the applied bias voltage of 10 kV was the most effective to both corrosion resistance and ICR, and its performance satisfies the demand for a bipolar plate in the Polymer Electrolyte Membrane Fuel Cells (PEMFC).

2010 ◽  
Vol 113-116 ◽  
pp. 2255-2261
Author(s):  
Dong Ming Zhang ◽  
Lu Guo ◽  
Liang Tao Duan ◽  
Zai Yi Wang

In the present study, we try to prepare hydrophobic film coated on stainless steel as the bipolar plate for polymer electrolyte membrane fuel cell (PEMFC). Magnetron sputtering (MS) was adoped to prepare the Cr3Ni2/Cr2N multi-layer coated on stainless steel. The corrosion resistance and electrical conductance of the coated substrate were tested. The water contact angles were measured. The film exhibits improved corrosion resistance and electrical conductance. The corrosion current is 0.58µA.cm-2 and the contact resistance at 240N.cm-2 is 8.5mΩ.cm2. Meanwhile, it is a kind of hydrophobic film with water contact angle of 107o. The performance shows strong dependance on microstructural characteristics. The nano-protrudes on the SS304/Cr3Ni2/Cr2N surface result in the film with hydrophobic property, just like the effect of lotus surface.


2017 ◽  
Vol 20 (4) ◽  
pp. 169-173
Author(s):  
Huihui Zhang ◽  
Juntao Yuan ◽  
Ming Zhu

In order to reduce interfacial contact resistance (ICR) and enhance corrosion resistance of 310 stainless steel (310 SS) for bipolar plates (BPs) of polymer electrolyte membrane fuel cell (PEMFC), TiN with styrene-butadiene rubber (SBR) coating was prepared by using electrophoretic deposition. Microstructure of TiN-SBR coated 310 SS prepared under different conditions was characterized by scanning electron microscopy (SEM), and a uniform, dense and well-bonded TiN-SBR coating was prepared at 30 V for 10 s in the suspension liquid containing 6.0 g/L SBR. Polarization behavior in the simulated service environment of PEMFC (1 M H2SO4 at 298 K) and ICR of the TiN-SBR coating deposited under the optimized conditions were investigated. The results showed that the TiN-SBR coating successfully decreased the anodic polarization current and ICR, indicating excellent interfacial contact resistance and corrosion resistance.


Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 183 ◽  
Author(s):  
Meiling Xu ◽  
Shumei Kang ◽  
Jinlin Lu ◽  
Xinyong Yan ◽  
Tingting Chen ◽  
...  

PEMFC are considered to be the most promising for automotive energy because of their good working effect, low temperature, high efficiency, and zero pollution. Stainless steel as a PEMFC bipolar plate has unparalleled advantages in strength, cost, and processability, but it is easy to corrode in a PEMFC working environment. In order to improve the corrosion resistance, the surface modification of 316L stainless steel is a feasible solution for PEMFC bipolar plates. In the present study, the plasma-nitrided coating and CrNx coating were prepared by the plasma-enhanced balanced magnetron sputtering technology on the 316L stainless steel surface. The microstructures, phase compositions, and corrosion resistance behavior of the coatings were investigated. The corrosion behavior of the prepared plasma-nitrided coating and CrNx coating was investigated by potentiodynamic polarization, potentiostatic polarization, and electrochemical impedance spectroscopy (EIS) in both cathodic and anodic environments. The experimental results show that corrosion resistance of the CrNx coating was better than the plasma-nitrided coating. It was indicated that the technology process of nitriding first and then depositing Cr was better than nitriding only.


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.


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