【摘要】：質(zhì)子交換膜燃料電池(PEMFC)由于有著諸多優(yōu)越的性能,被認為是未來應(yīng)用前景最好和市場發(fā)展最重要的一種發(fā)電裝置。雙極板是承載著PEMFC重要功能的核心部件之一,占據(jù)了電池組絕大部分的重量及成本。與現(xiàn)有的石墨類雙極板材料相比,金屬類材料在抗氣體滲透能力、機械強度、規(guī)�；a(chǎn)加工及提高電池的比功率等方面的優(yōu)勢明顯,但金屬雙極板的腐蝕問題一直是制約其應(yīng)用發(fā)展的重要因素。本文主要研究了在316L不銹鋼板表面磁控濺射鉻涂層的沉積工藝,并對涂層腐蝕性能進行了研究；探索Cr涂層表面熔鹽電化學(xué)氮化機制,先在熔鹽體系中對不銹鋼雙極板表面進行電化學(xué)氮化研究,為在316L不銹鋼表面制備出性能優(yōu)異的Cr/CrxN涂層奠定研究基礎(chǔ)。采用直流磁控濺射技術(shù)在316L不銹鋼雙極板表面沉積Cr涂層,利用掃描電鏡對316L不銹鋼表面鍍Cr涂層進行微觀形貌觀察和分析,結(jié)果表明：當濺射電流由0.2A增加到0.25A時,涂層的表面晶粒尺寸增加；隨著沉積時間的延長,316L/Cr涂層更均勻致密。濺射不同時間的316L/Cr涂層在0.5mol/L H2SO4溶液中浸泡進行電化學(xué)測試得知：隨著濺射沉積時間增加,腐蝕電位變大,腐蝕電流密度會減小；濺射電流為0.25A、時間為3h的316L/Cr涂層在腐蝕溶液中浸泡768h后,其腐蝕電位仍保持較高,涂層仍保持很好穩(wěn)定性,能有效抑制基體合金的腐蝕。在LiCl-KCl-KNO2熔鹽體系中,采用電化學(xué)方法對316L不銹鋼表面進行氮化工藝研究。首先利用循環(huán)伏安法分析確定氮沉積電位,再采用恒電位法在316L不銹鋼表面沉積氮涂層。結(jié)果表明：在UCl-KCl-KNO2體系中的電化學(xué)氧化還原中,N3+還原成N的電位明顯低于Li和K離子還原成相應(yīng)堿金屬的電位；熔融LiCl-KCl-lmol%KNO2體系中,在480℃時N3+還原成N原子并滲入不銹鋼表面。滲氮層均勻致密,厚度約為10μm。
[Abstract]:Proton exchange membrane fuel cell (PEMFC) is considered to be the most important power generation device with the best application prospect and market development because of its excellent performance. Bipolar plate is one of the core components that carry the important function of PEMFC, which accounts for most of the weight and cost of battery pack. Compared with the existing graphite bipolar plate materials, metal materials have obvious advantages in gas permeability, mechanical strength, large-scale production and processing and increasing the specific power of batteries. However, the corrosion of metal bipolar plate has always been an important factor restricting its application and development. In this paper, the deposition process of magnetron splashing chromium coating on 316L stainless steel plate was studied, and the corrosion properties of the coating were studied. To explore the electrochemical nitriding mechanism of molten salt on the surface of Cr coating, the electrochemical nitriding of stainless steel bipolar plate was studied in molten salt system, which laid a foundation for the preparation of Cr/CrxN coating with excellent properties on 316L stainless steel surface. Cr coating was deposited on 316L stainless steel bipolar plate by DC magnetron sputter. The microstructure of Cr coating on 316L stainless steel surface was observed and analyzed by scanning electron microscope (SEM). The results showed that when the sputtering current increased from 0.2A to 0.25A, the coating was deposited on the surface of 316L stainless steel by scanning electron microscope (SEM). The surface grain size of the coating increases. With the prolongation of deposition time, 316L/Cr coating is more uniform and compact. The 316L/Cr coatings deposited in 0.5mol/L H2SO4 solution for different time were immersed in 0.5mol/L H2SO4 solution. The results showed that with the increase of deposition time, the corrosion potential increased and the corrosion current density decreased. After soaking the 316L/Cr coating in corrosion solution for 768 h with a sputter current of 0.25 A and a time of 3 h, the corrosion potential of the coating is still high and the coating is still stable, which can effectively inhibit the corrosion of the matrix alloy. The nitriding process of 316L stainless steel surface was studied by electrochemical method in LiCl-KCl-KNO2 molten salt system. Firstly, the nitrogen deposition potential was determined by cyclic volt-ampere method, and then the nitrogen coating was deposited on the surface of 316L stainless steel by potentiostatic method. The results show that in the electrochemical redox of UCl-KCl-KNO2 system, the potential of N _ 3 reduction to N is significantly lower than that of Li and K ions to the corresponding alkali metal. In the molten LiCl-KCl-lmol%KNO2 system, N _ 3 is reduced to N atom at 480 鈩，

本文編號：2486987