Non-destructive terahertz sensor for coatings
The new non-contact, multi-layer coatings sensor with scanning capability can determine the individual thickness of many paint layers on both metallic and non-metallic substrates. The Teracota called system uses a broadband pulse of terahertz light to illuminate the coated surface from a short distance. The reflected signal contains reflections at the interface of adjacent coating layers, and it is analyzed to determine the thickness of each layer.
The automotive paint process is the initial application area to determine the thickness of individual paint layers following baking. For this application, a successful operation has been demonstrated on all types of basecoats encountered: solid, metallic, and pearlescent.
Many materials are semi-transparent to terahertz radiation. When stratified materials, such as a coated substrate, are illuminated by a broadband terahertz pulse, a reflected signal is obtained. This reflected signal contains partial reflections from each of the interfaces in the sample, encoding information on the properties of each layer.
The details of this technology are explained in a recently released video by Teraview.