氮气流量对质子交换膜燃料电池316L不锈钢双极板TiN涂层性能的影响

为了提高316L双极板的耐蚀性和导电性，采用多弧离子镀方法在不同氮气流量下制备TiN涂层。使用X射线衍射(XRD)、场发射电子扫描电镜(SEM)、膜电极电阻检测设备、电化学工作站等对所制备的TiN涂层的结构及其性能进行表征。研究结果表明：(1)具有TiN涂层的316L金属双极板比没有涂层的316L不锈钢金属双极板具有能更好的耐蚀性以及导电性。(2)在模拟的质子交换膜燃料电池(PEMFC)阴极环境中随着氮气流量的增加具有TiN涂层的金属双极板的耐蚀性先增强后减小，接触电阻先变大后减小。当氮气流量为200 mL/min时候测的最低的接触电阻为9.62 mΩ/cm²和最低的电流密度5.19×10^-7 A/cm²,极化电阻最大为4.990×10⁴Ω,此时为最佳工艺。     

金属双极板TiCr膜层氯离子腐蚀的研究与模拟

为了研究金属双极板TiCr膜层的氯离子腐蚀规律和机理,采用磁控溅射方法制备以316L不锈钢为基体,TiCr为导电膜层的双极板材料。针对燃料电池和固体聚合物电解水电解池的内部溶液容易被氯离子污染的实际情况,借助电化学极化曲线和交流阻抗谱(EIS),考察了电解质溶液中氯离子浓度对TiCr膜层耐蚀性的影响。并且,通过分子模拟软件对氯离子影响合金膜腐蚀速率的机理进行了动力学模拟。测试和分子模拟结果表明,合金膜的腐蚀速率随氯离子含量的增加而增加,氯离子通过与合金钝化膜表面处金属原子之间的吸附-溶解过程,实现对膜层的加速腐蚀。     

医用316L不锈钢表面载药微孔制备技术

以0.3 mol/L草酸为电解液,利用磁控溅射镀铝与阳极氧化相结合的方法在医用316L不锈钢表面制备了亚微米至微米尺度的载药微孔.利用扫描电镜和X射线能谱对微孔表面形貌和元素分布进行观察和分析;并运用电化学极化曲线法研究了多孔316L不锈钢在生理盐水溶液中的腐蚀行为.研究结果表明:微孔的尺寸随着氧化电压的增加和氧化时间的延长而增大;且316L不锈钢的耐腐蚀性提高.     

金属双极板表面改性涂层的评价方法研究进展

理想的质子交换膜燃料电池（PEMFC）用金属双极板需要具备良好的耐蚀性和导电性,表面改性是解决金属双极板耐蚀性和导电性的主要途径之一。本文对金属双极板表面改性涂层的各种性能评价方法进行了归类、介绍、总结。表面改性金属双极板的性能评价方法主要有非原位的电化学腐蚀分析、界面接触电阻测量、表面形貌表征、组分分析以及原位的组装电池评价等,重点介绍了各种方法的基本原理、操作条件、结果分析以及应用情况等,发现电化学腐蚀分析的测试标准不统一、原位评估方法应用较少等问题,提出进一步分析测试参数影响并统一测试标准以及尽可能在电池运行环境中评估金属双极板性能的研究方向,期待后续研究能够尽快完善相关评价标准体系,促进行业规范有序发展。     

电刷镀镍过程中316L不锈钢表面状态的变化

利用X射线光电子能谱仪(XPS)、扫描电镜(SEM)、能谱仪(EDS)等设备研究了电刷镀镍各步骤对316L不锈钢表面状态的影响。清洗可有效地降低316L不锈钢表面的C含量;活化会对表面造成腐蚀,提高表面粗糙度;预镀镍可以获得仅有较少微裂纹的薄镀层。虽然刷镀镍层表面存在较多微裂纹,但仍可以满足钎焊对厚度、结合力和耐高温性能的要求。     

金属双极板在模拟直接甲醇碱性燃料电池环境中的电化学行为

直接甲醇碱性燃料电池(DMAFC)由于采用了碱性电解质膜,许多在酸性介质中无法使用的非铂金属成为可选的催化剂已经引起了大家的普遍关注。双极板,特别是金属双极板作为DMAFC中一个关键材料对电池的输出性能起着重要的作用,其腐蚀性的大小决定了燃料电池的使用寿命长短。迄今为止,金属双极板在DMAFC中的研究国内外少见报道。本文对比研究了不锈钢316L和石墨作为双极板在模拟DMAFC中的电化学性能。动电位和电化学阻抗谱分析结果表明:不锈钢316L腐蚀电流低于石墨,其极化电阻明显高于石墨,恒电位实验结果与Tafel曲线分析结果一致,验证了动电位和电化学阻抗谱的实验结果。说明在碱性环境中,金属双极板与电解质溶液之间的反应活性比石墨双极板低,为拓宽不锈钢316L在DMAFC的应用奠定了理论基础。     

316L不锈钢表面电镀镍工艺及其耐蚀性能研究

316L不锈钢由于其优异的耐蚀性常被用作石油开采行业中的设备制造。不锈钢因为腐蚀环境中H~+的存在而易被腐蚀,因此采用工业上广泛使用的电镀技术在不锈钢表面沉积镍镀层以提高不锈钢在含酸性介质中的耐腐蚀性并优化电镀镍涂层的制备工艺,获得最优耐腐蚀性能的镍镀层。本文在316L不锈钢表面利用正交实验,研究了一定条件下不同温度对镀层硬度及耐腐蚀性的影响,并通过扫描电子显微镜、X射线衍射谱图和硬度测试分析了工艺参数对镀层结构的影响。研究表明:在其他条件一定时,随着温度的升高,镍镀层的硬度也不断增加。在其它参数不变的情况下,电镀温度为60℃时,所得镍层硬度最佳、耐蚀性最好。     

激光前处理磁控溅射镀铜涤纶织物的制备及性能

采用激光对涤纶织物表面进行前处理,再利用磁控溅射技术在其表面镀覆纳米铜薄膜。镀铜涤纶织物采用能谱仪、X射线衍射仪和扫描电镜进行表征,且评价了其导电性、拒水性及颜色。结果表明,激光前处理加溅射镀膜所得镀铜织物表面致密地沉积了纳米铜,铜镀层具有良好的结晶性,为面心立方结构。镀铜涤纶织物对水的接触角高达128.5°,方块电阻为3.5?/sq。     

磁控溅射离子镀金装饰膜的研究

采用磁控溅射离子镀技术在316不锈钢表面制备TiN层和Au层,TiN层的厚度分别为0.620μm、0.997μm和1.389μm,反应沉积时间分别为60min、100min和140min,Au层的厚度均为0.13μm左右。测试了镀金层的镀层表面形貌、色泽、耐腐蚀性能和耐磨性能。结果表明,镀膜的反应沉积时间不同时,镀层表面均较致密,中间层TiN层的厚度对颜色没有明显的影响,镀层的耐腐蚀性和耐摩擦性能良好。     

磁控溅射TiN/Au–Cu复合薄膜的性能及其变色机理研究

以磁控溅射法在316不锈钢上制备了TiN中间层厚度约为0.7μm,表面Au–Cu合金层厚度约为0.2μm的玫瑰金色复合薄膜,并对其进行耐人工汗液腐蚀和耐磨损性能测试.结果发现,TiN层具有良好的耐磨损性能,但腐蚀试验后复合膜层发生了明显变色.采用光学显微镜、扫描电镜、能谱分析和X射线光电子能谱仪分析了复合薄膜的变色机理.结果表明,该玫瑰金色薄膜表面变色主要与Cu元素的氧化有关.     

Carbon coated stainless steel bipolar plates in polymer electrolyte membrane fuel cells

The desirable properties of the metallic bipolar plates in polymer electrolyte membrane fuel cells (PEMFC) are good corrosion resistance, high electrical conductance, hydrophobicity, and low cost. In this study, carbon films are deposited on stainless steel 316L (SS316L) samples by close field unbalanced magnetron sputtering. The AFM, SEM, and Raman results show that the carbon film is dense, continuous, and amorphous. The corrosion resistance, hydrophobicity, and interfacial contact resistance (ICR) of the carbon coated steel are investigated and compared to those of uncoated SS316L. The deposited carbon film has high chemical inertness thereby significantly enhancing the corrosion resistance of the coated SS316L. Furthermore, the carbon coated SS316L is more hydrophobic and the resulting ICR is elevated to that of graphite. Our results indicate that the properties of the carbon coated SS316L are better than those of conventional graphite bipolar plates.     

Corrosion resistant low temperature carburized SS 316 as bipolar plate material for PEMFC application

One of the current challenges for application of PEM fuel cell is to find corrosion resistant, electrically conductive, light weight, cost competitive bipolar plate material. Low temperature carburization (LTC) of stainless steels is a novel, patented process by Swagelok Company. This paper addresses the corrosion resistance characteristics of LTC SS 316 for polymer electrolyte membrane fuel cell (PEMFC) bipolar plate applications. Corrosion properties of this material were studied using potentiodynamic and potentiostatic tests in simulated (1 M H₂SO₄ + 2 ppm HF, 0.5 M H₂SO₄, pH: 4.0, and 5% HCl + 5% Na₂SO₄) PEMFC conditions. LTC SS 316 showed excellent corrosion resistance in these conditions compared to SS 316. The mechanism of anodic dissolution and general corrosion of LTC SS 316 was observed to be similar to SS 316 however the extent of LTC SS 316 corrosion was less. LTC SS 316 showed corrosion currents well below 16 μA cm⁻² in anodic and cathodic atmospheres under potentiostatic conditions. The potentiostatic current rapidly falls to ∼4.0 and ∼1.5 μA cm⁻² under anodic and cathodic conditions, respectively. LTC SS 316 was observed to form a thinner oxide layer as compared to SS 316 after 24 h of potentiostatic testing. Moreover LTC SS 316 lowered the interfacial contact resistance by approximately 24% as compared to SS 316 after corrosion testing. Hence this study clearly states the performance advantage of using LTC SS 316 as bipolar plate material as compared to conventional materials.     

Electrochemical,SEM and XPS investigations on phosphoric acid treated surgical grade type 316L SS for biomedical applications

A simple surface pre-treatment method was attempted to establish a stable passive layer on the surface of surgical grade stainless steel (SS) of type 316L for biomedical applications. Surgical grade type 316L SS specimens were subjected to H₃PO₄ treatment for 1 h by completely immersing them in the acid solutions to develop a passive barrier film. The effect of various concentrations of phosphoric acid on the localized corrosion resistance behavior of type 316L SS was investigated through electrochemical techniques using cyclic polarization studies and electrochemical impedance spectroscopy (EIS). X-ray photoelectron spectroscopy (XPS) was used to evaluate the nature and composition of the passive films. The surface morphology and relative elemental composition of the untreated and acid treated surfaces subjected to anodic polarization was studied by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) techniques, respectively. Compared with untreated (pristine) 316L SS, the 40% acid treated surface formed a stable passive layer that had superior corrosion resistance.     

Effects of Potential on Corrosion Behavior of Uncoated SS316L Bipolar Plate in Simulated PEM Fuel Cell Cathode Environment

The effect of potential on the corrosion behavior of uncoated stainless steel SS316L as bipolar plate material in proton exchange membrane (PEM) fuel cell cathode environment is studied. Electrochemical methods, X‐ray photoelectron spectroscopy, scanning electron microscope are employed to characterize the corrosion behavior of SS316L at different polarization potentials in PEM fuel cell cathode environment. The results show that the corrosion current density of SS316L increases with the increase of polarization potential significantly. When the potential is higher than 0.7 V versus SCE, severe corrosion occurs on SS316L. The work also shed light on the corrosion mechanisms of SS316L at different potential in the PEM fuel cell cathode environment.     

A Promising Alternative to PEMFC Graphite Bipolar Plates: Surface Modified Type 304 Stainless Steel with TiN Nanoparticles and Elastic Styrene Butadiene Rubber Particles

In order to utilise inexpensive bipolar plates for proton exchange membrane fuel cells (PEMFC), a surface modification with TiN nanoparticles and elastic styrene butadiene rubber (SBR) particles has been applied to the most widely commercialised stainless steel of type 304 which did not satisfy the required properties in the bare form. The electro‐conducting agglomerates were electrophoretically deposited on the stainless steel bipolar plates. The surface modification greatly improved the corrosion resistance of the stainless steel as well as the interfacial contact resistance (ICR). As a result, the cell performance was significantly enhanced and become comparable to that with graphite bipolar plate during operation for 1,000 h. Ac‐impedance results indicated that the TiN–SBR coating was effective not only in reducing the ICR but also in retaining the resistance low throughout the operation. The hydrophobic character of the TiN–SBR coating on the stainless steel bipolar plates, which facilitated the removal of the formed water in the cathode side during the single cell operation, is also responsible for the enhanced cell performance. Therefore, the type 304 stainless steel bipolar plate modified with the electro‐conducting nanosized TiN – elastic SBR particles is suggested to be a promising substituent for the PEMFC graphite bipolar plate.     

Corrosion properties and cell performance of CrN/Cr-coated stainless steel 316L as a metal bipolar plate for a direct methanol fuel cell

CrN/Cr-coated stainless steel (STS) 316L is investigated as the material for a metal bipolar plate for a direct methanol fuel cell (DMFC) under actual operating circumstances. Protective coating layers of CrN/Cr are formed on STS 316L using an unbalanced magnetron (UBM) DC sputter via Cr target in an effort to improve the corrosion resistance and long-term stability of the STS 316L. In a corrosion resistance test, the CrN/Cr-coated STS 316L shows much better corrosion resistance than bare STS 316L in simulated electrolytic environments under anodic and cathodic potentials relevant to DMFCs. The interfacial contact resistance (ICR) between CrN/Cr-coated 316L and carbon paper decrease to 4 mΩ cm² at a compaction force of 150 N cm⁻² compared to bare STS 316L (570 mΩ cm²). The CrN/Cr-coated STS 316L cell has better cell performance compared to the bare STS 316L cell. Furthermore, the CrN/Cr-coated STS 316L cell exhibit low voltage losses of 38.2 μV h⁻¹ under long-term operation of 760 h. These results show that the CrN/Cr-coated STS 316L, demonstrating its feasibility for use as a metal bipolar plate in a DMFC under actual operating circumstances.     

Corrosion behavior of amorphous carbon deposit in 0.89% NaCl by electrochemical impedance spectroscopy

Amorphous carbon films were deposited on SS316L substrates using a DC magnetron sputtering system, aiming at the application of the coated SS316L for biomedical implants. The biocompatibility and chemical stability of the carbon layers have been previously demonstrated. The films were deposited on top of sputtered titanium coatings introduced as a buffer layer to enhance film-substrate adhesion. The corrosion resistance of the a-C/Ti/SS316L systems was investigated by electrochemical techniques. The electrolyte used in this work was 0.89 wt.% NaCl at pH 7.4, which simulates body fluid ionic concentrations. The coated samples displayed corrosion resistance values in the saline solution much higher than the stainless steel substrates and the role of the Ti coating thickness was analysed in order to determine the optimal system for biological applications.     

Corrosion resistance of poly p-phenylenediamine conducting polymer coated 316L SS bipolar plates for Proton Exchange Membrane Fuel Cells

The usage of conducting polymers as coating materials for bipolar plates to prevent corrosion is the recent trend in Proton Exchange Membrane Fuel Cell (PEMFC) technology. Paraphenylenediamine (pPD) monomer was electropolymerized to poly p-phenylenediamine (PpPD) over 316L SS. The characterization of PpPD, the conducting polymer coating, over 316L SS was done using attenuated total reflectance infra-red (ATR-IR) spectroscopy to confirm the formation of PpPD. The surface morphology and topography were studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The corrosion protection performance of the coating was evaluated using open circuit potential (OCP) measurement, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies in PEMFC environment. EIS studies revealed that the charge transfer resistance for the coated substrates has increased by one order of magnitude than the bare substrate. Potentiodynamic polarization studies have registered lower corrosion current density by one order magnitude for the 0.06 M pPD coated substrate than the bare substrate and the polarization resistance values for the coated substrates have increased by two and a half time than the bare substrate. These results showed that PpPD coated substrates exhibited enhanced corrosion resistance in PEMFC environment.     

磷钼酸在酯化反应体系中对316不锈钢的腐蚀抑制机理

采用扫描电子显微镜(SEM)和X射线光电子能谱(XPS)研究了模拟醋酸丁酯反应(CH3COOH、H2SO4、H3PMo12O40,105℃)条件下316不锈钢(316SS)的表面形貌和元素组成。结果表明,磷钼酸经物理吸附在不锈钢表面形成保护层,并发生氧化还原反应,生成的水合物、氧化物、难溶盐类沉积在不锈钢表面,形成致密的钝化膜,从而抑制316SS的局部腐蚀,阻止点蚀的扩散和蔓延,PMo12O430-、MoO42-和CrO42-使钝化膜表层具有阳离子选择性,能阻挡SO24-通过该膜到达金属表面,膜内层结晶态氧化物具有阴离子选择性,阻止基体金属离子穿过钝化膜而溶解,从而抑制局部腐蚀的进一步扩展。     

Electrochemical corrosion characteristics of type 316 stainless steel in simulated anode environment for PEMFC

The corrosion behavior of type 316 stainless steel in simulated anode environment for proton exchange membrane fuel cell (PEMFC), i.e., dilute hydrochloric acid solutions bubbled with pure hydrogen gas at 80 °C, was investigated by using electrochemical measurement techniques. The main purpose is to offer some fundamental information for the use of stainless steels as bipolar plate material for PEMFC. Both polarization curve and electrochemical impedance spectroscopy (EIS) measurements illustrate that 316 stainless steel cannot passivate spontaneously in the simulated environments. The absorbed (and/or adsorbed) hydrogen atoms from cathodic corrosion reactions on the steel surface may deteriorate the passivity and corrosion resistance. The oxidation of these hydrogen atoms gives rise to a second current peak in the anodic polarization curve, and the current increases with immersion time. EIS spectra also reveal that a porous corrosion product layer formed on the steel surface during the active dissolution in the test solutions. 316 stainless steel exhibits the similar corrosion behavior in sulfate ions containing dilute hydrochloric acid solution.