A novel high temperature resistant Mo-Cu functional gradient coating for optic fiber Bragg grating

摘要

A novel metal gradient coating of optic fiber, which contains a molybdenum (Mo)-copper (Cu) functional gradient layer and a nickel (Ni) protective layer, is fabricated by magnetron sputtering and electroplating processes, respectively. According to the thermal shock resistance test, the optic fiber with this metal gradient coating has good thermal stability and reliability at 800?°C. A simple temperature mathematical model of optic fiber Bragg grating (FBG) sensor coated with Mo-Cu functional gradient layer and Ni protective layer is used to calculate temperature sensitivity, and simulates the stress of the metal gradient coating by ANSYS. Optic and thermal tests are performed to evaluate the characteristics of metal gradient coating of FBG sensor. Compared with the simple Mo-Cu-Ni multilayer coating, the metal gradient coating reduces the thermal stress by 5.5?kpa and inhibits the effect of the metal coating sensitized FBG, which are 15.27?pm/°C and 15.54?pm/°C, respectively. These results indicate that fiber optic metal gradient coating has great potential applications for high-temperature sensing.