Distributed quantum dot sensors for monitoring the integrity of protective aerospace coatings

The development of a non-destructive health-monitoring system for painted metal structures is being pursued. The system is based on sensing the fluorescence emission intensity of quantum dot particles that have been distributed throughout protective aerospace coatings. The quantum dots serve as distributed sensors that can provide localized information on the corrosive conditions that exist within the paint film. Consequently this provides an early indication of several key aspects, which include: the quality of film application; the in-service loss of corrosion inhibitor; and the mechanisms of failure. In this paper we present the successful distribution of CdSe/ZnS core-shell nanoparticles into a commercial chromate-inhibited aerospace primer and demonstrate a correlation between available levels of hexavalent chromium corrosion inhibitor and quantum dot photoluminescence during accelerated corrosion testing. The development of a non-destructive inspection device utilizing a microchannel gated intensifying camera is in progress. Finally, we discuss the limitations of available quantum dot materials and provide a vision for non-destructive corrosion inspection in metal structures.