Hybrid Sol–gel thin films for magneto-optical applications: Chemical, optical and tribological study

International audienceSol–gel processes are promising strategies to prepare materials with synergetic or complementary behaviour between a polymer and an inorganic matrix interacting at the molecular scale. The conditions of soft chemistry allow the integration of photocurable organic compounds into an inorganic network, opening the way to the creation of new nanocomposite materials deposited on wide surfaces. The objective of the present study is to develop a process in order to prepare doped thin solid film for magneto-optical applications. The main steps of the process are the deposition (by hydrolysis condensation) and characterization of an organically modified silicon alkoxide containing zirconium alkoxide to modulate the refractive index of the film. After deposition, UV irradiation allows to develop an organic structure entangled in the inorganic network. For various applications, tribological studies on these new materials cannot be bypassed since these future components may be submitted to various mechanical solicitations. The resulting thin films, exhibiting a high transparency with a modulable refractive index, have a great potential to be used for components in integrated optical devices. The friction and wear behavior of the films has been investigated depending on the deposition conditions, mainly the organic conversion ratio ranging between 6 and 98%. The organic conversion ratio corresponds to the range of organic network within the film. For the lowest organic conversion ratios, the films do not withstand the friction tests and exhibit poor wear resistance. For conversion ratios above 60%, friction coefficients in the 0.1 range have been recorded, with a significant wear resistance. The tribological behaviors of such inorganic-organic hybrid nanocomposite thin films tested in standard conditions are discussed in agreement with their structure and composition. The potentiality to reach both wear resistance and outstanding optical properties will be evaluated