The Effects of Nitrogen Content on the Mechanical and Tribological Properties of CrTaWN x Thin Films.

In the study described herein, CrTaWN_x thin films were deposited on Si and 304 stainless-steel (SUS304) substrates through magnetron co-sputtering using CrW and Ta targets. The nitrogen flow ratio (f_N2 = [N₂/(N₂ + Ar)]) was adjusted to 0.05, 0.2, 0.4, and 0.5 to fabricate CrTaWN_x films with various N contents. The CrTaWN_x films prepared at a low f_N2 of 0.05 exhibited a low stoichiometric ratio x of 0.16 and a nanocrystalline structure. In contrast, the CrTaWN_x films fabricated at an f_N2 of 0.2–0.5 exhibited x values of 0.42–0.62 and formed a face-centered cubic phase. The nanocrystalline (Cr_0.34Ta_0.20W_0.46)N_0.16 film exhibited mechanical properties and wear resistances that were inferior to those of the crystalline CrTaWN_x thin films. A (Cr_0.38Ta_0.15W_0.47)N_0.55 film exhibited a hardness of 25.2 GPa, an elastic modulus of 289 GPa, and a low wear rate of 0.51 × 10⁻⁵ mm³/Nm. [ABSTRACT FROM AUTHOR]