Thermally nitrided stainless steels for polymer electrolyte membrane fuel cell bipolar plates: Part 1: Model Ni–50Cr and austenitic 349™ alloys
Thermally nitrided stainless steels for polymer electrolyte membrane fuel cell bipolar plates: Part 1: Model Ni–50Cr and austenitic 349™ alloys
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DOI：
10.1016/j.jpowsour.2004.06.067
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发表时间：
2004-11
影响因子：
9.2
通讯作者：
Heli Wang;M. Brady;G. Teeter;J. Turner
中科院分区：
文献类型：
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作者：
Heli Wang;M. Brady;G. Teeter;J. Turner
模型Ni-50Cr合金在纯氮气中于1100℃热氮化2小时，可形成连续的、具有较低界面接触电阻的CrN/Cr2N保护层。然而，对349Cr349™奥氏体型不锈钢采用类似的氮化工艺，会导致不连续的CrN、Cr2N和(Cr，Fe)2N1−x(x=0-0.5)相表面颗粒的混合物覆盖在暴露的γ奥氏体基基体上，而不是连续的氮化物表层。氮化处理显著降低了349™的界面接触电阻。然而，在模拟的质子交换膜燃料电池环境中(1M H_2SO_4+2ppm F-−溶液，在70℃下用氢或空气喷雾)，在阳极和阴极条件下都观察到非常高的腐蚀电流。这种不良的行为与在349™上形成的富铬氮化物表面缺乏连续性有关。讨论了在不锈钢合金表面实现连续的、保护性的氮化铬表面层的问题。
Thermal nitridation of a model Ni–50Cr alloy at 1100°C for 2h in pure nitrogen resulted in the formation of a continuous, protective CrN/Cr2N surface layer with a low interfacial contact resistance. Application of similar nitridation parameters to an austenitic stainless steel, 349™, however, resulted in a discontinuous mixture of discrete CrN, Cr2N and (Cr,Fe)2N1−x(x = 0–0.5) phase surface particles overlying an exposed γ austenite-based matrix, rather than a continuous nitride surface layer. The interfacial contact resistance of the 349™ was reduced significantly by the nitridation treatment. However, in the simulated PEMFC environments (1M H2SO4+ 2ppm F−solutions at 70°C sparged with either hydrogen or air), very high corrosion currents were observed under both anodic and cathodic conditions. This poor behavior was linked to the lack of continuity of the Cr-rich nitride surface formed on 349™. Issues regarding achieving continuous, protective Cr-nitride surface layers on stainless steel alloys are discussed.