Abstract
The integrity and reliability of surface protective coatings deposited on metal surface could be in-situ monitored via the attractive luminescence sensing technique. In this paper, we report the influence of substrate temperature on the properties of erbium (Er) doped aluminum nitride (AlN) film, which could be applied as a luminescent layer for monitoring the health of multilayered Al/AlN coating. The AlN:Er films were deposited via reactive radio-frequency magnetron sputtering, and the silicon substrate temperature was varied from non-intentional heating up to 400 °C. The composition, morphology, crystalline structure, and dielectric function of the AlN:Er films deposited under these different substrate temperature conditions were studied. These properties of the AlN:Er films show strong correlation with the substrate temperature maintained during film fabrication. The obtained AlN:Er films, without further annealing, exhibited photoluminescence peaks of the Er3+ ions in the visible wavelength range and the strongest photoluminescence intensity was observed for the AlN:Er film deposited with the temperature of substrate kept at 300 °C. The results demonstrated in this work offer guidance to optimize the substrate temperature for the deposition of AlN:Er film for future application of this sensing technique to thin metal components.
Highlights
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
Substrate temperature dependent properties of aluminum nitride (AlN):Er thin films prepared by reactive radio-frequency magnetron sputtering have been illustrated in this work
The XPS results signify that the fabricated AlN films were uniformly doped with Er3+ ions; the cross-sectional morphology observations via FESEM illustrates that the AlN:Er films were made of dense and compact columnar structures, regardless of the substrate temperature concerned in this work; the surface morphology investigation via Atomicforce force microscopy (AFM) reveals that the RMS roughness is merely ~6.1 ± 1.0 nm for the AlN:Er films deposited at 300 ◦ C, compared to the largest roughness of 22.6 ± 1.0 nm for the non-heated counterpart; the evolution of the reflection patterns obtained via GIXRD were explained via the study of the crystallographic unit lattice of hexagonal wurtzite AlN; the Williamson-Hall approach has been applied to the reflection patterns to obtain the average crystallite size, and the results indicate that the
Summary
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. The local failures of the surface protective coating, such as cracks and delamination sites, could be detected in-situ and non-destructively and repairing treatment could be applied to the local failures to prolong the service lifetime of the surface protective coating. This sensing technique is a promising approach for evaluating the integrity and reliability of surface protective coatings prepared on reactive metals. For such a case, multiple luminescent layers, doped with rare-earth ions emitting at different wavelengths, as depicted, could be embedded in the surface protective coating to evaluate the extent of failure Multiple luminescent layers, doped with rare-earth ions emitting at different wavelengths, as depicted in Figure 1b, could be embedded in the surface protective coating to evaluate the extent of failure
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
