具有低接触电阻的燃料电池双极板用Ti-Al-Ta合金  

Ti-Al-Ta alloy for fuel cell bipolar plates with low contact resistance

作　　者：宋梦凡 王清[1] 董闯[1,2] SONG Mengfan;WANG Qing;DONG Chuang(Key Laboratory of Materials Modification by Laser,Ion and Electron Beams(Ministry of Education),Dalian University of Technology,Dalian 116024,Liaoning,China;School of Materials Science and Engineering,Dalian Jiaotong University,Dalian 116028,Liaoning,China)

机构地区：[1]大连理工大学三束材料改性教育部重点实验室,辽宁大连116024 [2]大连交通大学材料科学与工程学院,辽宁大连116028

出　　处：《材料工程》2024年第12期80-90,共11页Journal of Materials Engineering

基　　金：国家重点基础研究项目基金项目(2020JCJQZD165);大连市科技创新基金重点学科重大课题(2020JJ25CY004)。

摘　　要：表面制备涂层后的钛及钛合金作为质子交换膜燃料电池双极板具有优良的综合性能,但裸板在服役过程中会形成导电性不良的钝化膜,降低了整机效率。通过研究α型耐蚀钛合金Ti35(Ti5Ta)及其Al合金化的可行性,在保证耐蚀性的前提下,提高裸板的导电性。利用团簇式成分设计方法,结合相图上的最高固溶度,设计了成分为Ti-7Ta,Ti-8.3Ta,Ti-9.6Ta的三种Ti-Ta合金以及成分为Ti-2.6Al-5.8Ta,Ti-3.8Al-8.6Ta,Ti-5Al-11.3Ta的三种Ti-Al-Ta合金。测试结果可知,在模拟阴极服役环境(0.5 mol/L H_(2)SO_(4)+2×10^(-6)HF)0.6 V(vs.SCE)下恒电位极化4 h,所设计合金阴极极化电流密度均小于参照合金TC4,其中Ti-8.3Ta合金最小为0.72μA·cm^(-2)。在1.5 MPa加载压力下,随着Ta含量的增加,接触电阻(ICR)值逐渐降低,且均优于纯钛和TC4合金,Ti-5Al-11.3Ta合金的ICR值最小,为18.3 mΩ·cm^(-2),其阴极极化电流密度为0.91μA·cm^(-2)。综上表明,Ta和Al的适量添加能够有效提升钛合金双极板的服役性能,有望实现无涂层制备的钛合金双极板材料。Titanium and titanium alloys with surface-prepared coatings have excellent overall performance as bipolar plates for proton exchange membrane fuel cells,but the bare plates will form passivation films with poor electrical conductivity during service,reducing the efficiency of the whole machine.By studying the feasibility ofα-corrosion resistant titanium alloy Ti35(Ti5Ta)and its Al alloying,the electrical conductivity of bare plate was improved on the premise of ensuring corrosion resistance.Using the clustertype composition design method developed by the group and combing with the highest solid solution degree on the phase diagram,three kinds of Ti-Ta alloys with compositions of Ti-7Ta,Ti-8.3Ta,and Ti-9.6Ta and three kinds of Ti-Al-Ta alloys with compositions of Ti-2.6Al-5.8Ta,Ti-3.8Al-8.6Ta,and Ti-5Al-11.3Ta were designed.The experimental results show that the cathodic current density of the developed alloy is lower than that of the reference alloy TC4 under the simulated cathodic service environment(0.5 mol/L H_(2)SO_(4)+2×10^(-6)HF)at a constant potential polarization voltage of 0.6 V(vs.SCE)for 4 h.The cathodic current density of the designed alloy is lower than that of the reference alloy TC4,among which the Ti-8.3Ta alloy has the smallest value of 0.72μA·cm^(-2).Under 1.5 MPa loading pressure,with the increase of Ta content,the interfacial contact resistance(ICR)value gradually decreases and is better than that of the pure titanium and TC4.The ICR value of Ti-5Al-11.3Ta alloy is the smallest,which is 18.3 mΩ∙cm^(-2),and its cathodic polarization current density is 0.91μA·cm^(-2).In summary,the appropriate addition of Ta and Al can effectively improve the service performance of titanium alloy bipolar plates,and it is expected to realize the preparation of titanium alloy bipolar plate materials without coating.

关 键 词：钛合金 双极板 耐蚀性 界面接触电阻 钝化膜 

分 类 号：TB31[一般工业技术—材料科学与工程] TK91[动力工程及工程热物理]