Research in corrosion protection has been increasing since the 18th century, especially with respect to steel.
Galvanizing is a common protective means, but during the production process initial corrosive spots are formed right at the cut-edge. The idea that is developed at the MPIE is to incorporate microcapsules, which are filled with corrosion inhibitor, e.g. polyphosphomolybdate, into the zinc coating. As soon as the steel sheet is cut, the zinc starts to corrode and dissolve.
This is the starting shot for the intelligent, second protective system: the capsules are released from the zinc onto the steel and smeared along the surface by the cutting device. The inhibitor can be released and thus protects the steel surface.
Modification with thiols facilitates the integration into the zinc
“This is an intelligent protective system that automatically realises when and where corrosion happens, becomes active and stops again when the respective spot is healed”, explains Dr. Rohwerder, group leader in the department of Interface Chemistry and Surface Engineering. It works like a scratch in the skin: it is detected, healed and the initial status is restored.
For preparing these smart coatings, three work steps must be performed: loading of the silica microcapsules with the inhibitor, sealing them to avoid premature leaching and finally incorporating the capsules into the zinc layer.
The sealing procedure, however, has of course an immense influence on the release kinetics. By rinsing with water glass solution, the release is steady and slow. The incorporation into the zinc layer is the most difficult part. Unmodified, the hydrophilic particles are repulsed by the zinc and only adsorb on the surface.
Tabrisur Rahman Khan, a PhD student from Bangladesh, has now fixed the problem. He modifies the particles with zinc affine functional groups, such as thiols, which make the solvation feasible.
Max-Planck & Fraunhofer collaboration on intelligent corrosion coatings
Everything solved? Well, not completely. For efficient protection, a higher loading of the pores with the inhibitor must be realised. This is the focus of current research. Additionally, the concept of intelligent corrosion coatings has been expanded to systems with polymer coatings. The joint project ASKORR (Aktive Schichten für den Korrosionsschutz, active coatings for corrosion protection) is a successful collaboration between the Max-Planck and the Fraunhofer Society in this field.
Two Max-Planck and two Fraunhofer Institutes are sharing their competences with respect to nanocomposite coatings, agent containers, zinc coatings and the analysis of effective mechanisms in order to improve the protective coatings. “It is a huge challenge, but present results look very promising”, states Rohwerder.
1 Gesellschaft für Korrosionsforschung
Yasmin A. Salem, M.A.
Max-Planck-Institut für Eisenforschung GmbH
phone: +49 (0)211 6792 722
fax: +49 (0)211 6792 218
Yasmin A. Salem | Source: MPIE
Further information: www.mpie.de
More articles from Automotive Engineering:
Progressive optics for side mirrors ends automobile blind spots without distorting view
29.01.2013 | Optical Society of America
Motion Control Keeps Electric Car’s Four Wheels—and Four Motors—on the Road
24.01.2013 | Ohio State University
A fried breakfast food popular in Spain provided the inspiration for the development of doughnut-shaped droplets that may provide scientists with a new approach for studying fundamental issues in physics, mathematics and materials.
The doughnut-shaped droplets, a shape known as toroidal, are formed from two dissimilar liquids using a simple rotating stage and an injection needle. About a millimeter in overall size, the droplets are produced individually, their shapes maintained by a surrounding springy material made of polymers.
Droplets in this toroidal shape made ...
Frauhofer FEP will present a novel roll-to-roll manufacturing process for high-barriers and functional films for flexible displays at the SID DisplayWeek 2013 in Vancouver – the International showcase for the Display Industry.
Displays that are flexible and paper thin at the same time?! What might still seem like science fiction will be a major topic at the SID Display Week 2013 that currently takes place in Vancouver in Canada.
High manufacturing cost and a short lifetime are still a major obstacle on ...
University of Würzburg physicists have succeeded in creating a new type of laser.
Its operation principle is completely different from conventional devices, which opens up the possibility of a significantly reduced energy input requirement. The researchers report their work in the current issue of Nature.
It also emits light the waves of which are in phase with one another: the polariton laser, developed ...
Innsbruck physicists led by Rainer Blatt and Peter Zoller experimentally gained a deep insight into the nature of quantum mechanical phase transitions.
They are the first scientists that simulated the competition between two rival dynamical processes at a novel type of transition between two quantum mechanical orders. They have published the results of their work in the journal Nature Physics.
“When water boils, its molecules are released as vapor. We call this ...
Researchers have shown that, by using global positioning systems (GPS) to measure ground deformation caused by a large underwater earthquake, they can provide accurate warning of the resulting tsunami in just a few minutes after the earthquake onset.
For the devastating Japan 2011 event, the team reveals that the analysis of the GPS data and issue of a detailed tsunami alert would have taken no more than three minutes. The results are published on 17 May in Natural Hazards and Earth System Sciences, an open access journal of ...
22.05.2013 | Life Sciences
22.05.2013 | Ecology, The Environment and Conservation
22.05.2013 | Earth Sciences
17.05.2013 | Event News
15.05.2013 | Event News
08.05.2013 | Event News