液态锤砧快速凝固V-Al-Fe(…)滤氢合金多尺度结构调控与氢传输性能

The purification of hydrogen gas based on hydrogen permeable metal membranes is one of the central parts for hydrogen energy economy. It is desirable to develop new metal membrane materials with lower cost and higher performance to replace the precious Pd-based alloy membranes which are presently used in industry. Rapid solidification technology based on splat quenching method is used to prepare a new kind of hydrogen permeable membranes of V-Al-Fe(…) alloys. The formation and evolution of solidification structure and its multiscale structure characteristics are investigated. The relationship is built between the multiscale structure and hydrogen transport properties including hydrogen solubility, diffusivity and permeability. The hydrogen embrittlement, hydrogen flux stability and durability during long-term hydrogen permeation are investigated and the potential mechanisms are discussed in the context of the hydrogen-metal interaction. These generate an effective route to modulate the multiscale structure for the significant improvement in hydrogen transport properties of the alloys. This work provides a new idea to prepare low cost and high performance hydrogen permeable metal membranes of V-based alloys.

基于滤氢金属膜的氢气提纯是氢能源产业化应用的核心内容。目前工业应用的滤氢金属膜是极为昂贵的钯合金，亟待开发低成本、高性能的新型膜材料。本项目拟采用液态锤砧快速凝固技术制备V-Al-Fe(…)新型滤氢合金，深入考察不同凝固条件下组织形成规律及其多尺度结构特征，揭示多尺度结构与氢溶解、扩散和渗透等传输行为的内禀关系，阐明氢渗透过程氢与多尺度结构相互作用对氢脆、氢渗透稳定性和持久性的影响规律及机制，从而确立多尺度结构调控技术路线，全面优化合金氢传输性能。本项目既瞄准工业氢气提纯领域对低成本、高性能滤氢金属膜应用的迫切需求，亦可为我国开发具有自主知识产权的新型V基滤氢合金提供思路和理论基础。

滤氢金属膜是氢气提纯、高纯氢气制备的核心材料，广泛应用于电子工业、航空航天、燃料电池和核聚变等领域。目前，工业应用的膜材料是贵金属Pd及其合金。本项目基于晶格匹配，开发了V-Al-M(M:Fe,Cr,Ni,Co…)系列滤氢合金。通过在V中添加M和Al，显著降低氢溶解，提高抗氢脆性能；另外，M原子半径小于V，Al原子半径大于V，M和Al同时添加可实现与纯V相近的晶格，确保低氢溶解下保持高氢扩散特性，达到渗氢性能和抗氢脆性能的良好匹配。系统研究了V-Al-M系合金铸态组织和氢传输性能。其中，V90Cr5Al5具有最低的氢溶解和最高的氢扩散性能，在623 K纯氢气氛下的氢渗透系数为2.5×10-7molH2m-1s-1Pa-0.5 (Pd的16倍)。在V90Cr5Al5基础上，添加Cu元素，开发了具有bcc-(V)和fcc-(Cu)的双相固溶体型的氢分离合金。fcc-(Cu)相的引入明显提高了钒合金的塑性变形能力，通过冷轧加工制备了厚度0.1mm的薄膜。热处理后，(V90Cr5Al5)90Cu10表现出最优的渗氢流量和抗氢脆性能。进一步研究了模拟工业环境下，轧制热处理 (V90Cr5Al5)90Cu10合金膜的膜表面不同气体竞争吸附条件下的氢传输行为与机制。本项目研究已发表15篇SCI论文，其中5篇论文发表在本领域top1期刊Journal of Membrane Science；另外，在国际著名期刊International Journal of Hydrogen Energy、Separation and Purification Technology发表多篇论文。1篇论文获《特种铸造及有色合金》年度优秀论文。授权国家发明专利2项。