EuroBlech 2018

••• 17 ••• Innovationen Joining metals without welding Kiel research team uses its “nanoscale sculpturing” process to roughen the surface W elding is still the stand- ard technique for joining metals. However, this laborious process carried out at high tem- peratures is not suitable for all ap- plications. Now, a research team from the “Functional Nanomate- rials” working group at Kiel Uni- versity, together with an industry partner, has developed a versatile alternative to conventional weld- ing and gluing processes. Based on a special etching pro- cess, it enables aluminium and aluminium alloys to be joined with each other as well as with polymers, forming a durable and strong joint. When welding, com- ponents are joined by locally melt- ing them at the connection point. However, the high temperatures required for this influence the ma- terial in the so-called heat-affect- ed zone, causing structural as well as optical changes. It also requires special safety precautions and ap- propriately qualified staff. In con- trast, the process developed by the Kiel University research group led by Professor Rainer Adelung not only spares the materials to be joined, but it is also easier and more flexible to use, even in hard- to-reach places such as corners or upside down on the ceiling. In just a few minutes, metals can be permanently connected with each other, but also with polymers. The team envisages areas of ap- plication such as ship, aircraft or vehicle production. The process is particularly well-suited for sub- sequently attaching components in existing constructions, for ex- ample, in the interiors of ships or cars, explained Adelung regarding possible applications. “The high temperatures of welding will de- stroy surfaces that have already been treated and painted, for ex- ample. Our process, on the other hand, works at room temperature without special protective meas- ures,” said Adelung. To be able to connect metals, the Kiel research team uses its “na- noscale sculpturing” process to roughen the surface with a pre- cise electro-chemical etching pro- cedure, so that a fine, rectangular hook structure is created on the micrometre level. When two of these treated surfaces are inter- locked using an adhesive, a strong joint is created which is very diffi- cult to break. The aluminium flange is firmly attached to the aluminium wall. Photo: Siekmann / CAU