Low infrared emissivity and corrosion resistance of TiO₂ films prepared by thermal oxidation of sputtered Ti films

To develop low infrared emissivity and corrosion resistant films, a dense rutile TiO₂ film was synthesized by thermal oxidizing sputtered Ti metal film under hypoxic environment at 300, 400, 500 and 600℃. Results show that with rising oxidation temperature, surface defects and oxygen vacancies decrease. At 300℃ and 400℃, less oxygen leads to pores. As temperature increases, surface grains become smaller and denser, and films change from hydrophilic to hydrophobic. At 500°C, the TiO₂ film with emulsion - like morphology and protrusions has a contact angle of 148.75° (near superhydrophobic), enhancing corrosion resistance. At 600°C, the increase in carrier density reduces resistivity, and the densely packed structure minimizes infrared absorption, achieving a low infrared emissivity of 0.125 in 8–14 μm wavelength range.