【摘要】 利用团簇式方法,通过对Fe-Cr-Ni合金进行成分精修,在保持合金良好耐蚀性的同时,提升不锈钢的导电性。首先,解析316L不锈钢的成分,获得其Fe-Cr-Ni基础成分的理想团簇式[Ni-Fe₁₁Ni₁]Cr₃,进而,固定Cr₃,将Ni含量（质量分数）从6.63%变到32.74%,得到符合团簇成分通式[Ni-Fe_13-xNi_x-1]Cr₃=Fe_13-xNi_xCr₃ （x=1～5）的合金成分。利用真空电弧熔炼并铜模浇注成直径10 mm试棒,随后进行固溶及水淬处理。实验结果表明,在模拟双极板服役环境(0.5 mol/L H₂SO₄+2×10^-6 HF)下,随着Ni含量提高,在酸钝化后,自腐蚀电流密度由14.39μA/cm²降低至1.00μA/cm²,在电化学氮化后,由1.03μA/cm²降低至0.29μA/cm²。这些数据均优于参照合金316L不锈钢（分别为7.51和0.47μA/cm²）,甚至低于0.5μA/cm²的目前产业目标。在0.064 MPa压力下接触电阻逐渐减小（酸钝化后,从1.16Ω·cm²减至0.98Ω·cm²,电化学氮化后,从1.07Ω·cm²减至1.03Ω·cm²）,优于316L不锈钢的1.1Ω·cm².上述实验结果表明,Ni含量的持续添加能够提升合金作为双极板的使役性能,最佳的不锈钢成分配方为[Ni-Fe₁₀Ni₂]Cr₃,可以作为替代316L的新型不锈钢。电化学氮化处理方法在提升合金耐蚀性的同时,保持了相当高的接触电阻,是较好的不锈钢双极板表面处理方法。更多还原

【Abstract】 316 stainless steel is the first choice for bipolar plate material in fuel cells;however,it suffers from passivation-induced corrosion and conductivity deficiencies.In this work,Fe-Cr-Ni alloy was refined using the cluster-plus-glue-atom model to obtain stainless steels with balanced corrosion and electrical performances.For austenite 316 L stainless steel,the unit is described as a 16-atom cluster formula [Ni-Fe₁₁Ni₁]Cr₃.By fixing the three atoms of a glue,Cr₃ is required to achieve sufficient corrosion resistance,and new compositions with varying Ni contents are designed following [Ni-Fe_13-xNi_x-1]Cr₃=Fe_13-xNi_xCr₃（x=1-5）.The designed alloys were arc melted at least five times,copper-mold suction casted into 10-mm cylindrical rods under an argon atmosphere,homogenized at 1150℃ for 2 h,and water quenched.Under the simulated bipolar plate service environment(0.5 mol/L H₂ SO₄+2×10^-6 HF aqueous solution),as the Ni content increases,the self-corrosion current density decreases to 1.10 and 0.29 μA/cm² after acid passivation and electrochemical nitridation,respectively.These values are well below compared to the commercial 316 L stainless steel（7.51 and 0.47 μA/cm²） and close to the current industry target（0.5 μA/cm²） for bipolar plates.At the same time,the contact electrical resistance（under0.064 MPa pressure） decreases to 0.98 and 1.03 Q.cm2 after acid passivation and electrochemical nitridation,respectively,which is superior to the 316 L stainless steel（1.1 Ω·cm²）.Thus,optimal alloy composition [Ni-Fe₁₀Ni₂]Cr₃ can be used as the right substrate material of the bipolar plate instead of the 316 L stainless steel.The electrochemical nitridation method is the proper surface treatment method for stainless steel bipolar plates,and this method improves the alloy’s corrosion resistance while maintaining the same level of contact resistance.更多还原