Yung-I Chen

Internal oxidation and mechanical properties of Ru based alloy coatings

Ru based laminated coatings with various transition metal solutes were deposited on silicon wafers using a direct current magnetron cosputtering system. After annealing in a 1% O2–Ar atmosphere at 600 °C for 30 min, Ti–Ru, Zr–Ru, Mo–Ru, Hf–Ru, and W–Ru coatings were internally oxidized and maintained a laminated structure, consisting of alternating oxygen-rich and deficient layers stacked along the original growth direction. Conversely, V–Ru and Cr–Ru coatings exhibited external oxidation and failed to maintain the laminated structure after annealing, due to the fast outward diffusion of V and Cr. The variations in crystalline structure and nanohardness of Ru based coatings caused by oxidation after annealing were investigated.

Mechanical properties and oxidation behavior of ZrNx thin films fabricated through high-power impulse magnetron sputtering deposition

ZrNx thin films were deposited on silicon substrates using novel high-power impulse magnetron sputtering. The films were annealed at 600 °C in an atmosphere of 15 ppm O2–N2, and their performance as a protective hard coating on glass molding dies was evaluated. The as-deposited ZrNx thin films were characterized by a high nanohardness of 26–27 GPa and low surface roughness of approximately 0.5 nm. However, the mechanical properties of the ZrNx thin films declined after they were annealed owing to the formation of ZrO2 scales.

Internal oxidation of laminated Hf–Ru coatings

This study explored the internal oxidation of laminated Hf–Ru coatings by using cyclical gradient chemical concentration distribution along the growth direction. Hf-rich, near-equiatomic, and Ru-rich Hf–Ru coatings were prepared using direct-current magnetron cosputtering. Oxidation was examined by annealing the coatings at 500 and 600 °C in a 1% O2–99% Ar atmosphere for 30 min. The results indicated that internally oxidized laminated Hf–Ru coatings formed after annealing at 600 °C. Hf preferentially oxidized and formed monoclinic HfO2. The Ru-rich Hf0.11Ru0.89 coatings exhibited a higher oxidation resistance and superior mechanical properties.