Metallurgical Aspects of Ni-Coating and High Temperature Treatments for FBG Spectrum Regeneration

Abstract

The structural integrity of mechanical components is assessed by FBG sensors in many industrial fields. The FBG sensor has a relevant application at very high or low temperatures. To avoid the variability of the reflected spectrum and the mechanical properties degradation of the FBG sensor, metal coatings have been used to guarantee the grating’s integrity in extreme temperature environments. Particularly, at high temperatures, Ni could be a suitable selection as a coating to improve the features of FBG sensors. Furthermore, it was demonstrated that Ni coating and high-temperature treatments can recover a broken, seemingly unusable sensor. In this work, two main objectives were pursued: first, the determination of the best operative parameters to achieve the most compact, adherent, and homogeneous coating; second, the correlation between the obtained morphology and structure and the FBG spectrum modification, once Ni was deposited on the FBG sensor. The Ni coating was deposited from aqueous solutions. By performing heat treatments of the Ni-coated FBG sensor, it was investigated how the wavelength (WL) varied as a function of temperature and how that variation was caused by the structural or dimensional change of the Ni coating.

Low-Dimensional Structures for Smart Materials and Composites: Preparation, Properties and Applications

“…In summary, the paper underscores a research about the significance of Mo in shaping the properties of ZnO rods and provides valuable insights into the potential applications of Mo-doped ZnO materials. Lupi et al [19] introduced an innovative electrodeposition process aimed at depositing fiber-optic-Bragggratings (FGBs) with a Ni coating The authors investigated the evolution of the coating properties (i.e., grain-growth and oxidation). This aspect was of utmost importance as it provided insights into the behavior of the sensors under extreme temperature conditions.…”