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

在金属制造和金属使用工业中存在越来越大的压力，以去除固体和液体夹杂物，例如脱氧产物、硫化物、氮化物、碳化物等，从而提高金属清洁度。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很大的影响。该合作研究中心的愿景是通过熔体过滤创造新一代金属质量，具有上级机械性能，用于轻质结构和高要求建筑材料。该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来大量减少金属基体中的非金属夹杂物。特别是在第三时期，新一代联合精炼过滤系统将成为焦点。金属熔体首先与反应性过滤器接触，该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。结果，发生夹杂物朝向熔体表面上的炉渣的一种漂浮。此外，高反应性以及气泡有助于细小夹杂物聚集成大的团簇，所述大的团簇由于浮力而流到熔体的表面或在活性过滤器的表面上过滤，所述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性质，用于足够的粘附，并因此用于夹杂物的充分过滤。用这种方法可以实现高于95%的纯化。建模主要集中在气泡的几个贡献和反应过滤器表面上原位形成的反应层上，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进行端部成形。 过滤器在铸造过程中的流动动力学条件对于过滤器宏观结构的正确设计是非常重要的。基于所研究的过滤机理的材料以及流量计算机辅助微观和宏观结构过滤器设计将导致高净化效率以及铸钢、铁、铝和镁部件的上级性能-强度、断裂韧性、疲劳。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.