Multi‐Functional Filters for Metal Melt Filtration

Abstract

Safety for road and railway vehicles as well as aircrafts requires highly stressable metallic components. The efficiency of these components is highly determined by the materials quality and purity. During the production process, contaminations within the metal melt can occur resulting in defects in the form of inclusions. It is difficult or even sometimes impossible to reduce or remove those inclusions. Within the Collaborative Research Center 920 “Multi-functional filters for metal melt filtration – a contribution toward zero defect materials” funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) in 2011 at the Technische Universität Bergakademie Freiberg focuses on researching 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 center is an enormous reduction of non-metallic inclusions in the metal matrix by the use of intelligent filter materials as well as filter systems due to functionalized filter surfaces. So called “active” coatings based on the same chemistry as the inclusions can attract more effective the non-metallic particles and lead to a higher deposition on the filter surface. In addition, new “reactive” coatings are investigated in terms of a chemical reaction between the functionalized filter surface and the gases in the metal melts. The surface design, the tailored thermal shock performance with regard to sufficient corrosion and creep resistance are most challenging tasks requiring an understanding of the control of the structural properties of the filter materials in the nano-, micro-, and macro-ranges, interaction at interfaces as well as temperature related phase transformations. The flow dynamic conditions in the filter during casting are of great importance for the proper design of the filter macro-structure. A material as well as a flow computer aided micro- and macrostructure filter design based on investigated filtration mechanisms can lead to high filtration efficiencies with superior properties – strength, fracture toughness, fatigue- of the casted steel, iron, aluminum, silicon, and magnesium components. In addition, other applications such as recycling of metals, the electronic industry via filtration of copper, or the thin steel and aluminum foil production can adapt part of the generated results. The present special issue focuses in a comprehensive way on selected results covering the entire chain of filtration, from the research of the filter materials, the agglomeration and deposition of inclusions on the functionalized filter surfaces, up to properties of the end metallic product. A total of 16 scientific projects with more than 20 funded researchers are working together by bridging different disciplines. A very important subject is also the qualification of the research assistants with the aim of getting a doctorate degree completed by different soft skills. On behalf of the whole team, we would like to thank all the journal editors as well as review members and invite you to share with us our results and awake your curiosity getting in touch with our CRC for fruitful discussions in this interdisciplinary scientific field. Christos G. Aneziris Institute of Ceramic, Glass and Construction Materials