On the potential of Er-doped AlN film as luminescence sensing layer for multilayer Al/AlN coating health monitoring

Substrate Temperature Dependent Properties of Sputtered AlN:Er Thin Film for In-Situ Luminescence Sensing of Al/AlN Multilayer Coating Health

“…Room temperature photoluminescence (PL) of the fabricated AlN:Er film without further annealing was recorded by a fluorescence spectrometer (Thermo Scientific DXR, Waltham, MA, USA). The film characterization details were similar to our previous work [6].…”

“…The diameter of the Al target was 2 inches and it was doped with 2.0 at.% of Er via arc-melting. The reason of choosing this doping level is that it provides the best photoluminescence efficiency [6,24,25]. The substrate was polished Si (100) and the working gas was a mixture of argon (70%) and nitrogen (30%).…”

“…The power applied to the magnetron was 300 W and sputtering time was 60 min for all the samples. More experimental thin film fabrication details could be found in our previous work [6].…”

“…Initially, the concept of luminescence sensing was proposed for in-situ monitoring of the health of thermal barrier coating deposited on hot components, such as metal blades, working in aggressive environments of gas turbines. An optical thin film doped with luminescent ions could be prepared under the thermal barrier coating, and luminescence could be detected when the thermal barrier coating was deteriorated by corrosion or wear [1,2,3,4,5,6].…”

“…The intention of our work is to apply the luminescence sensing technique, via the deposition of a thin layer of AlN:Er film under the Al layer, to evaluate the coating health of the Al/AlN multilayer. Additionally, our previous study has demonstrated the viability of such an approach [6]. However, to apply such luminescent AlN:Er layer on thin metal components, which easily suffers from heat deformation, the substrate temperature is a key parameter that needs to be considered in the fabrication process.…”