Characterization of Multilayer Coatings Using Shaped Field Electromagnetic Sensor Arrays

In this program we will develop the capability to rapidly characterize, over large areas, the properties of multi-layer coatings used in specialized aircraft for electrostatic and electromagnetic integrity. The measured coating properties will be the thickness of the conducting layer, the conductivity and/or magnetic permeability of the conducting layer, and the thickness of the nonconducting transition and topcoat layers. At the core of the proposed approach are JENTEK’s MWM-Arrays, which are inductive, eddy-current-based sensors, fabricated on conformable flexible substrates, and JENTEK’s multivariate inverse methods, used to obtain simultaneous and independent estimates of multiple unknown material properties from MWM-Array measurements. This proposed technology has several substantial advantages over existing inspection methods: (1) the MWM-Arrays are operated in scanning mode, producing spatially registered, two-dimensional (C-scan) digital images of coating properties over large areas in real time; (2) no reference standards are required; (3) information is provided on multiple material properties in a single pass. Northrop Grumman Aerospace Systems (NGAS) will support JENTEK in the performance of this proposed Phase I program. BENEFIT: If this program is successful, the Air Force would be provided with a tool to detect and image the thickness of individual layers of a multi-layer coating stack and the electromagnetic properties of the conducting layer. This would reduce maintenance costs and improve fleet readiness and mission capability. The commercial market for characterization of multi-layered coatings is substantial, including commercial aerospace, spacecrafts, and corrosion protection systems.