Inclusion of fluorophores in hybrid sol-gel coatings; application to in situ temperature measurements

New organic—inorganic sol-gel films have been prepared starting from a mixture of silicon and zirconium alkoxides using a synthesis process of several steps. Coatings loaded with a fluorescent CaF2:Yr2+ powder have been deposited on stainless steel rendered adhesive by a special oxidative surface treatment. The final deposits have successfully supported drastic adherence standard tests after several dips into liquid nitrogen, and have been used for temperature-dependent fluorescence decay measurement. The loaded gels have been coated on a rotating cylinder into liquid nitrogen and the fluorescence decay measurement device is described. Efficient measurements can be registered at rotating speeds as fast as 4000 rpm.