ZrNx (x = 0.67–1.38) films were fabricated through direct current magnetron sputtering by a varying nitrogen flow ratio [N2/(Ar + N2)] ranging from 0.4 to 1.0. The structural variation, bonding characteristics, and mechanical properties of the ZrNx films were investigated. The results indicated that the structure of the films prepared using a nitrogen flow ratio of 0.4 exhibited a crystalline cubic ZrN phase. The phase gradually changed to a mixture of crystalline ZrN and orthorhombic Zr3N4 followed by a Zr3N4 dominant phase as the N2 flow ratio increased up to >0.5 and >0.85, respectively. The bonding characteristics of the ZrNx films comprising Zr–N bonds of ZrN and Zr3N4 compounds were examined by X-ray photoelectron spectroscopy and were well correlated with the structural variation. With the formation of orthorhombic Zr3N4, the nanoindentation hardness and Young’s modulus levels of the ZrNx (x = 0.92–1.38) films exhibited insignificant variations ranging from 18.3 to 19.0 GPa and from 210 to 234 GPa, respectively.

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Ta-Al multilayer coatings were fabricated through cyclical gradient concentration deposition by direct current magnetron co-sputtering. The as-deposited coatings presented a multilayer structure in the growth direction. The oxidation behavior of the Ta-Al multilayer coatings was explored. The results specified that Ta-rich Ta-Al multilayer coatings demonstrated a restricted oxidation depth after annealing at 600 • C in 1% O 2 -99% Ar for up to 100 h. This was attributed to the preferential oxidation of Al, the formation of amorphous Al-oxide sublayers, and the maintenance of a multilayer structure. By contrast, Ta 2 O 5 formed after exhausting Al in the oxidation process in an ambient atmosphere at 600 • C which exhibited a crystalline Ta 2 O 5 -amorphous Al-oxide multilayer structure.

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