SFB 920: Multifunctional Filters for Metal Melt Filtration - a Contribution to Zero Defect Materials

金属制造和金属利用工业面临着越来越大的压力，需要去除固体和液体夹杂物，如脱氧产物、硫化物、氮化物和碳化物等，从而提高金属的清洁度。金属中非金属夹杂物的大小、类型和分布对铸件的力学性能有相当大的影响。该合作研究中心的愿景是通过熔体过滤创造新一代具有优异机械性能的金属品质，用于轻质结构和高要求的建筑材料。合作研究中心的目标是通过使用智能过滤材料以及具有功能化过滤表面的过滤系统，大大减少金属基体中的非金属夹杂物。特别是在第三阶段，新一代的联合精炼过滤系统将是重点。金属熔体首先与反应性过滤器接触，反应性过滤器在熔体中产生气泡并激活夹杂物表面上的气泡。其结果是，夹杂物向熔体表面的矿渣浮选。此外，高反应性和气泡有助于细夹杂物聚集成大簇，这些簇由于浮力流到熔体表面或在活性过滤器表面上过滤，活性过滤器不形成气泡，但在其功能化表面上提供与夹杂物相同的化学物质，以获得足够的粘附性，从而使夹杂物得到充分的过滤。用这种方法可以达到95%以上的纯度。建模主要集中在气泡的几种贡献和反应性过滤器表面上原位形成的反应层，以及它们生成关于过滤器的热机械和功能特性的代码，用于过滤器结构的3d打印，然后借助机器人辅助火焰喷涂技术对其进行末端成型。浇注过程中过滤机内部的流动动态情况对过滤机宏观结构的合理设计具有重要意义。基于已研究的过滤机制，一种材料以及流动计算机辅助的微结构和宏观结构过滤器设计将使铸钢、铁、铝和镁部件具有高的净化效率和优异的性能——强度、断裂韧性、疲劳性。此外，其他应用，如电子工业通过过滤铜或薄铝箔生产将受益于科学成果。在不久的将来，更高的材料效率和减少能源和二氧化碳排放的目标越来越接近。

There exists an increasing pressure on the metal making and metal using industry to remove solid and liquid inclusions such as deoxidation products, sulfides, nitrides carbides etc. and thereby improve metal cleanliness. It is well known that size, type and distribution of non-metallic inclusions in metal exert considerable effects on the mechanical properties of the cast products. The vision of this collaborative research centre is to create a new generation of metal qualities via melt filtration with superior mechanical properties for use in light weight structures and high demand construction materials. The aim of the collaborative research centre is an enormous reduction of non metallic inclusions in the metal matrix by the use of intelligent filter materials as well as filter systems with a functionalized filter surface. Especially in the third period a new generation of combined refining filter systems will be the focus. The metal melt comes first in contact with a reactive filter which generates gas bubbles in the melt as well as activates gas bubbles on the surface of the inclusions. As a result a kind of flotation of the inclusions towards the slag on the surface of the melt takes place. Further the high reactivity as well as the gas bubbles contribute to the agglomeration of the fine inclusions to big clusters which flow due to buoyancy forces to the surface of the melt or are filtrated on the surface of active filters, which do not form gas bubbles but provide on their functionalized surfaces the same chemistry as the inclusions for a sufficient adhesion and as a result for a sufficient filtration of the inclusions. With this approach a purification higher than 95 % can be achieved. The modelling is focusing mainly on the several contributions of the gas bubbles and on the in situ formed reactive layers on the surface of the reactive filters as well as they generate codes with respect to the thermomechanical and functional properties of the filters for a 3D-printing of filter structures which are then end shaped with the aid of a robot-assisted flame spraying technique. The flow dynamic conditions in the filter during casting are of great importance for the proper design of the filter macrostructure. A material as well as a flow computer aided micro- and macrostructure filter design based on investigated filtration mechanisms will lead to high purification efficiencies with superior properties – strength, fracture toughness, fatigue- of the cast steel, iron, aluminum and magnesium components. In addition other applications such as the electronic industry via filtration of copper or the thin aluminum foil production will profit from the scientific results. The target for a higher material efficiency and reduction of energy and CO2-emissions is coming closer in the near future.