SMARCOAT’s major technical achievements
We are halfway through the SMARCOAT project, so bellow are some of the achievements in the quest for nanostructured coatings for corrosion and impact sensing.
Release properties of nanocontainers: Different materials developed for controlled release of sensing species were investigated. The release profile of sensing species was determined under different triggering conditions associated with coating degradation and corrosion onset. Kinetic models were used to fit the experimental data.
Protocols for Substrate Preparation: Studies on surface pre-treatments of Mg alloys (AZ31, AM50 and Al free experimental alloy), Al alloy AA2024-T3 and CFRP for coating with polymeric materials containing nano-containers and/or LDH were performed. The developed procedures are expected to improve coating adherence.
Corrosion mono-sensitive system for Mg alloys: smart sensing additive developed by UAVR and scaled up by industrial partner SMT was incorporated into a water-based lacquer from industrial partner SYNPO and a polyetherimide system (HZG). As metal substrate for Mg AZ31 and the Al-free test alloy from HZG were selected. Principle characterization of the coatings in sense of sensor distribution were carried out by SEM/EDX, IR, Raman and EIS measurements. The detection of corrosion on AZ 31 and on the Al-free Mg alloy was successful and, in general, demonstrates that the aim of encapsulation of sensing compounds and their further incorporation into polymeric coating formulations is reached.
Corrosion mono-sensitive system for aluminum alloy 2024: A nanostructured polymeric coating system was developed for the corrosion sensing of AA2024. The system is based on nanocontainers encapsulating a pH sensing compound (SMT) and incorporated into a water borne lacquer (SYNPO). The coating system also passed successfully different coating standard tests relating to its formulation rheology, hardness, mechanical properties and corrosion protection.
Mechanical damages mono-sensitive system for FRP: The concept of mono-sensitive systems for the indication of mechanical damages was realized by developing a model epoxy laminated composite. Sensitive layers were developed and for each sensitive layer the threshold load for the damage visualization was defined with and without additional protective layer. Experimental characterization of morphological and mechanical characteristics of microcapsules of several types was performed, by using optical microscopy, dynamic light scattering, scanning electron microscopy and atomic force microscopy, which will be used upon further analytical modelling of the mechanical properties of single microcapsules.
Verification of impact sensing: The verification of impact sensing was done for the microcapsules and system of smart coating with element of construction. This includes different mechanical tests to estimate the impact sensing of the material under operating conditions. A method for the manufacture of a glass fiber reinforced plastic containing a sensitive layer with a damage visualization capability was developed. It was established that both shear and compression strain above the threshold of sensitivity of the layer leads to color appearance. The kinetics of the halochromiс transformation in room conditions was estimated.
The proof of concept has been done. Now we are heading towards improving the sensibility of the systems, the development of detection methods, upscale of the systems to achieve the first prototypes by the end of the project.
