Euroguss 2020

•••2••• Innovationen New technology for hybrid components The scientists from Fraunhofer IFAM have developed a new series-capable joining technology F or trendsetting lightweight con- struction concepts, connec- tions consisting of lightweight metals and fibre composites rep- resent ideal material combina- tions. In the past, components consisting of CFRP (carbon fibre reinforced plastics) and aluminium were preferably glued, riveted or bolted. The resulting disadvan- tages were the complex pretreat- ment of the adhesive surfaces and the additional weight increase in riveted and screwed connections. For hybrid components joining is therefore the better option. Unique challenges to all technologies However, as both materials show different electrochemical po- tentials, there is the danger of contact corrosion occurring in a hybrid composite. Within the framework of a DFG research project, Fraunhofer IFAM, in co- operation with the Faserinstitut Bremen e.V., has developed a new series-capable joining technol- ogy for the combination of cast aluminium and CFRP. Through a temperature-resistant protective layer on the CFRP component, the electrochemical corrosion processes in the composite mate- rial can be prevented. At the same time, this layer also ensures a firm connection. The combination of fibre compos- ite materials and lightweight ma- terials presents unique challenges to all established joining technol- ogies. In addition to the need for high connection strengths to be maintained, the joining itself should not add any significant weight. Contact corrosion must also be prevented for both ma- terials. In addition to adhesively bonded or riveted hybrid connec- tions, the hybrid high-pressure die casting presented here offers a new approach to save weight while simultaneously permanent- ly preventing the problematic is- sue of contact corrosion. A hybrid component in just a few steps Within the newly developed pro- cess, prior to the casting the CFRP structures are partially coated with a highly temperature stable plastic (PEEK), which does not be- gin to significantly decompose un- til temperatures of around 550 °C have been reached. In a subsequent casting process step, the CFRP components are placed into the high-pressure casting die and are cast in the area of the plastic with alumini- um at a temperature of around 700 °C. Through a targeted and controlled high-pressure die cast- ing process with short cycle times as well as the selection of suitable process and material parameters, an integration of the plastic into the high-pressure casting pro- cess is possible, despite the tem- perature differences, without the properties of the plastic being af- fected. Thus, a stable connection is created between the two ma- terials during the initial manufac- ture of the aluminium component by casting. Thus, time-consuming processing steps or pre-treatment of the joining surfaces are not necessary. Holding bracket produced using the hybrid casting technology Photo: Fraunhofer IFAM Zinklamellenbeschichtungen: höchster Korrosionsschutz und definierte Funktion Aalberts Surface Treatment GmbH ist Lizenzpartner der marktf ührenden Zinklamel- lenanbieter und an den weltweiten Standorten mit modernster Appli- kationstechnik vertreten. Zinkla- mellensysteme sind lackähnlich und enthalten in spezielle Binde- mittel dispergierte Pigmente und metallische Plättchen / Lamellen, die aus unterschiedlichen Legie- rungsbestandteilen zusammenge- setzt sein können. Der Zinklamellen-Korrosions- schutz hat sich auf Grund des gro- ßen Einsatzspektrums nicht nur im Automobilsektor durchgesetzt. So ermöglichen Zinklamellenbe- schichtungen einen sicheren Korro- sionsschutz z.B. für hochfeste Stäh- le, ohne dass wasserstoffinduzierte Spannungsrisse auftreten können. Anwendungen für Zinklamel- lenbeschichtungen finden sich in folgenden Branchen bzw. Bautei- len: Automobilindustrie, Bau- und Landmaschinen, Befestigungs- elemente, Bremsenteile, Chas- sis-Komponenten, Federn, Ge- windeteile, Luftfahrt, Stanzteile, Wind-Offshore-Anlagen Die Merkmale von Zinklamel- lenbeschichtungen sind wie folgt: • Dünne Schichten, je nach An- forderung 7 – 25 μm • Keine Wasserstoffversprödung im Prozess • Geringstes Wasserstoff-Gefähr- dungspotential im Betrieb / un- ter korrosiver Belastung • Frei von Schwermetallen • Bester Korrosionsschutz für Leichtbaustrategien • Einsetzbar auf hochfesten Stäh- len • Sehr gute Fernschutzwirkung auch bei partieller Beschädi- gung • Prozesssichere Beschichtung von Hohlräumen und Dopplerflächen coating excellence Halle 7 Stand 7-134 info@aalberts-st.com www.aalberts.com/st Anzeige