Achieving high toughness and wear resistance for hard TaN-Ag films actuated by Ag

Abstract

Ceramic-Ag films with enhanced mechanical and tribological properties have been widely researched. Transition metal nitrides (TMNs) films as hard ceramic material with doping Ag atoms commonly show a nano-composite structure and possess the combination of high hardness and toughness. Herein, the TaN film with incorporating few Ag atoms (1.2 at.%) presents FCC solid solution structure according to the HRTEM and XPS results, accompanied by grain refinement. From the XPS valence band and HRTEM, the increased metallic characters in electronic structure of TM-N bonds and the decreased grain size results in the enhanced mechanical properties. The TaN-Ag film with solid-solution structure possesses higher hardness (36.1 GPa) and toughness (KIC = 1.48 MPa*m1/2), combined with an improved wear resistance (wear rate: ∼1.9 × 10−6 mm3/N*m). In addition, a relatively lower coefficient of friction (0.18–0.23) is achieved for TaN-Ag films from the lubrication of AgTaO3 activated by Ag atoms.