Effect of proton irradiation on the mechanical, structural, and optical properties of TiAlN coating

Titanium aluminium nitride (TiAlN) is a promising material for space application as protective, radiation-resistance coatings. During the operation in space such coatings are exposed to the flux of energetic particles. We present the results of the proton irradiation effect on the mechanical, structural, and optical properties of the TiAlN coating deposited by reactive magnetron sputtering. The irradiation with fluence of 5 · 1016 ion/cm 2 results in an increase of Young՚s modulus and nanohardness above the superhard level, while a further fluence increase (up to 2 · 1017 ion/cm 2 ) results in a decrease of these parameters. Surface smoothing after proton irradiation has been demonstrated by profilometry. It is shown that irradiation with protons results in an increase of specular reflectance. Diffuse reflectance increases to a lesser extent and only after irradiation with relatively low proton fluences ((2–5)· 1016 ion/cm 2 ).