反应合成FeAl多孔膜的孔结构特征及膜与支撑体的界面结合性能研究

Porous inorganic membranes are comprehensive used in energy saving and environmental field. They take key role for national economy continuity development. At present, it is difficult for porous ceramic and metal membtanes to use in high-tempreture corrosion enviroment due to their intrinsic properties. FeAl intermetallics have excellent high-temperature oxidation, sulfurization and molten salts resistance and good mechanics property and weldability. The difficult problems of high-temperature corossion atomsphere and fine particals (such as PM2.5) filtration can be solved by using porous FeAl membrane as filter. Therefore, based on the Kirkendall effect and the reaction between Fe and Al, the FeAl membrane with fine pore diameter was fabricated on the porous FeAl support with big pore diameter. The pore structure charateristics of FeAl membrane and binding properties of interface between membrane and support were studied. It includes that, the pore formation and evolution procedure and pore structure charateristics of porous FeAl membrane fabricated by solid hemi-diffusion and reaction synthesis; the matching between FeAl membrane and support including the bonding strength, heat stability, heat shake property and stress distribution state and its produce mechanism. Founding the relationship between the properties and fabrication process, achieving the free design and control of pore structure parameters and interface bonding property of porous FeAl membrane. The study can establish theoretical foundation for porous FeAl membrane in industry apply.

无机多孔膜广泛应用于节能环保等领域，对国民经济的可持续发展具有关键性作用。目前工业用陶瓷和金属多孔膜因材料本身的性能缺陷而很难服役于高温腐蚀性环境。FeAl金属间化合物兼具陶瓷和金属的优点，具有优异的高温抗氧化、硫化和盐腐蚀性能，优良的力学和抗热震性能。将FeAl作为多孔膜研究将有望解决高温含腐蚀性气氛和细微颗粒（如PM2.5）的过滤净化难题。为此，本项目拟利用Kirkendall效应和Fe、Al反应，在大孔径FeAl多孔支撑体上制备微孔径的FeAl多孔膜，研究FeAl多孔膜的孔结构特征及膜与支撑体的界面结合性能。主要包括：FeAl多孔膜的孔隙形成、演变规律以及孔结构特征；膜与支撑体界面的结合强度、热稳定性、抗热震性能、界面应力分布及应力产生机理；建立孔结构参数、界面结合性能与制备工艺的关系，实现孔结构参数及界面结合性能的自主设计与控制。研究工作可为FeAl多孔膜的工业应用奠定理论基础。

无机多孔膜广泛应用于节能环保等领域，在当今世界能源短缺、水资源匮乏和环境污染日益严重的情况下，膜分离技术得到了世界各国的高度重视，已成为改善人类生存环境、提高人们生活质量，推动国民经济可持续发展的重要基础性材料。目前工业用陶瓷和金属多孔膜材料因本身的性能缺陷而很难服役于高温腐蚀性环境。FeAl金属间化合物具有优异的高温抗氧化、硫化和盐腐蚀性能，优良的力学和抗热震性能。将FeAl制备成多孔膜将有望解决高温含腐蚀性气氛和细微颗粒的过滤净化难题。.主要研究了如下内容：1）FeAl 多孔膜的制备，研究了FeAl多孔膜反应合成过程中的物相变化，并对 FeAl 多孔膜的孔结构参数包括孔隙率、孔径、孔径分布、透气度、曲折因子等进行了测试表征；确定了反应合成过程中孔隙的形成和演变规律。2）研究了膜层厚度、Al含量及合成工艺对FeAl 多孔膜孔结构的影响。3）研究了FeAl支撑体与膜层结合界面的结合状态、膜基结合力及抗热震性能。.获得的重要结果及数据如下：1）反应合成过程中有Fe2Al5中间相生成，最终获得的多孔膜为单一的FeAl相。2）孔隙由粉末颗粒间隙孔，Kirkendall孔隙和反应生成孔的不断演变而成。3）膜层厚度从299.1um减小到135.5um时，FeAl多孔膜的最大孔径变化不大，透气度从38.5m3m-2kpa-1h-1增加到84.2 m3m-2kpa-1h-1。4）通过元素固态扩散和高温反应合成，FeAl支撑体与FeAl膜层获得了优良的冶金结合。Fe-25%Al多孔膜材料的膜基结合强度为7.8MPa；经100次高温至室温（最高温差为600℃-室温）的热震后，表观没有随热震过程温差的剧烈变化出现明显的改变，表明该多孔膜中膜基结合强度大于通过风扇强冷过程产生的热应力。. 由于FeAl多孔膜的膜基材质相同，并经历了高温反应合成过程，获得了具有冶金结合的界面，耐反冲洗压力大，使用寿命长，加之FeAl具有的优异的高温抗腐蚀性能，可知，本项目研究制备的FeAl多孔膜孔结构和应用性能优异。研究工作为FeAl多孔膜的工业应用奠定了理论基础。