Start date: October 2019
Supervisor: Professor N McMurray, Professor G Williams and Mr P Keli
Sponsoring company: BASF
The protective coatings industry is responding to the challenge to find a successful materials substitution for toxic anti-corrosion agents.
Chromium (VI) use has been assigned a “sunset” date of 2019 by the European Union, after which its use will be banned. There is now an urgent need to identify new, environmentally corrosion inhibitive technologies showing equivalent, or better protective capability.
This project provides an excellent opportunity to work collaboratively with a prominent company involved in the automotive coatings market, namely BASF Automotive, to develop new corrosion inhibitive technologies. The current state of the art, involving phosphate-based technology, remains limited, resulting in significant interest in exploiting the properties of intelligent-release pigments, in which corrosion inhibitive species are stored and only released “on demand” in the presence of aggressive corrosion-inducing agents. Furthermore, there is also a need to improve transport of the inhibitor species from the bulk of the coating, to the areas where they are required (e.g. defects where the underlying metal is exposed). Currently, only a finite quantity of inhibitor originating from the coating in the immediate vicinity of the defect may be available to protect exposed metal.
By introducing long-range percolation networks within the coating, it is hoped that enhanced transport of inhibitor to defect regions can produce significantly more effective corrosion inhibition at the exposed metal.
The Research Engineer will:
· Investigate the efficiency of inhibition at penetrative coating defects using current state of the art phosphate-based pigments and novel smart-release ion-exchange pigments containing various corrosion inhibitive species.
· Carry out a detailed study with varying in-coating loadings of the above pigments to evaluate the effect on speed of inhibitor release.
· Assess novel inhibitor delivery systems such as nanotube reservoirs, ion exchange resins and minerals, conducting polymer networks as a means of introducing a long-range percolation pigment network within the protective organic coating.
· Evaluate how long-range transport of inhibitor from an optimised system influences the mechanism of coating failure due to de-adhesion originating from anodic and/or cathodic disbondment in the vicinity of a penetrative defect.
The main thrust of the work being to develop -next-generation protective coatings for technologically important light alloy surfaces, typically aluminium and possibly magnesium automotive alloy grades, although the best performing technologies may also be applied to the protection of steel. This program will exploit outstanding expertise in advanced electrochemical scanning techniques, coupled with high throughput methodologies to quantify protection efficiency and provide mechanistic understanding of inhibition mechanisms.