Transparent Zr–Al–O oxide coatings with enhanced resistance to cracking

The article reports on structure, transparency and mechanical properties of Zr–Al–O oxide thin films with Zr/Al > 1 produced by reactive DC pulse dual magnetron sputtering. Special attention is devoted to the formation of transparent Zr–Al–O oxide films in the transition mode of sputtering and their unique properties. It is shown that (i) the transparent Zr–Al–O films can be deposited in the transition mode of sputtering with a high deposition rate aD achieving up to 80 nm/min at relatively low value of the magnetron target power density Wt ≈ 45 W/cm2, (ii) the Zr–Al–O films sputtered in the transition and oxides mode of sputtering are highly elastic and exhibit relatively high hardness (typically H ≈ 18 to 19 GPa), low effective Youngʹs modulus E⁎ satisfying the ratio H/E⁎ > 0.1 and high elastic recovery We up to 78%, and highly elastic Zr–Al–O oxide films with H/E⁎ > 0.1 exhibit an enhanced resistance to cracking.