Professor Marcus Rutner und doctoral student Jakob Brunow of Hamburg University of Technology develop a nanopatch for the metal infrastructure.
The nanopatch is an ultra thin coating which is deposited on critical details of heavily used and cyclically loaded metal infrastructure, such as bridges, to postpone crack initiation and significantly extending the lifetime of infrastructure, hence, avoiding premature blocking, repair measures or demolition of important traffic arteries. The scientists were awarded the Harburger Sustainability Award in 2021.
The highly durable nanopatch has a total thickness of about one-eighth of the human hair diameter and consists of about 160 alternating copper and nickel layers which are processed by electrodeposition. This nanolaminate coating is locally applied just on the vulnerable structural joints of steel bridges subjected to high frequent and heavy traffic due to trucks or freight trains. The focus in this study is on the welded joint (see Figure, details a and b). First investigations in this study reveal muliple and probably simultaneously acting material mechanims which enable a superior resistance of the nanolaminate coating against crack initiation and resulting in a multifold extension of lifetime of a cyclically loaded welded joint (see Figure, detail c). The scientists name the reduced roughness of nanolaminate coating, the tight lateral support of the coating preventing extrusions and intrusions, further, the interface density per volume causing deviaton of a crack at each single interface and energy absorption as possible material mechanisms.
These material mechanisms are currently under investigation in order to better understand the interaction of mechanisms and to be able to optimize and tune the coating for the specific level of cyclic loading in future. This novel technology could allow a significant extension of lifetime of steel bridges in future from currently 80-100 years to potentially several hundred years with only very reduced maintenance needs. „The steel industry is a big CO2-producer. With this nanostructured technology we aim at reducing the steel consumption of metal infrastructure and saving resources which has a significant impact on the environment“ says Professor Marcus Rutner.
The metal nanolaminate coating providing extended lifetime of welded joints could be interdisciplinary of interest.
About the Harburger Sustainability Award: The district Hamburg Harburg recognizes with this Sustainability Award outstanding innovative and sustainable projects of a single person, a group, company, organization, institution on an annual basis. The awarded project should ideally have an ecological, societal and economical impact.