Strain Mapping in Nanostructured Coatings

Nanostructured Ceramic Coatings deposited on metallic surfaces of engineering components have exhibited unprecedented durability for several years of operations in terms functionalilty and protective applications . Since coating binding and subsequent interactions with substrates are events occurring at the nanoscale, strain and phase mapping by synchrotron probe engineering affords a fertile landscape for controlled application of nanotechnology. To successfully exploit such opportunities, however, will require integrative studies of the roles of both phase and strain distributions in the dynamic systems that the plasma spray, CVD or other processes introduce. We have developed a unique in the world instrumentation in terms of three dimensional (3D) strain and phase mapping.  The mapping is accomplished using high energy (deeply penetrating) synchrotron radiation to perform high precision x-ray diffraction on small volumes (1 mm to a few cm) which are then integrated into high resolution 3D maps of the strain fields.  This paper will address strain mapping in n-Al₂O₃/TiO₂ nanostructured coatings with emphasis on the key important issues including:
·              How can the nanoscale building blocks be engineered to enable new paradigms of functional and protective nanostructured coatings?
·              How can these processes be sensed via nanoscale EDXRD strain and phase mapping platforms to yield new endpoints with relevance to naval applications?  
·              What are the underline structural and functional parameters in processing of these coatings which result in dramatic improvements in their performance.
Many of the key local properties of coatings that determine their strength and durability in field service world, accessible with this instrumentation such as,  stress/strain fields, texture/preferred-grain orientation, and crack/void occurrence, elastic strains due to external stresses, plastic deformation, and the interplay of all of the above will be discussed.
ACKNOWLEDGEMENTS: The authors acknowledge the support of Office of Naval Research under grant # N000140610880