Infrared optical and mechanical properties of ceramic coatings fabricated by aerosol deposition

The possibility and mechanical improvement of the infrared ceramic coatings fabricated on fluoride substrates at room temperature by aerosol deposition (AD) were investigated aiming to optical components for infrared applications and devices. The yttria coating possibility fabricated on barium fluoride substrates by the AD process was found by adjusting one of the deposition conditions. The optical and mechanical properties of the fabricated ceramic coatings, which are important in practical applications, were evaluated by transmittance and hardness measurements respectively. The mechanical hardness of the fabricated yttria single coatings was increased to 4 times higher than that of the barium fluoride substrates. Furthermore, by an additional layer on a barium fluoride substrate, the mechanical properties of the fabricated multi-coatings including an upper yttria layer were improved from that of the single yttria coating on the barium fluoride substrate, retaining the IR transmittance of the single yttria coating at the wavelength of 10um.