Structure and mechanical properties of (TiVCr)N coatings prepared by energetic bombardment sputtering with different nitrogen flow ratios

The (TiVCr)N coatings were deposited on Si substrate via rf magnetron sputtering of a TiVCr alloy target under dc bias in a N2/Ar atmosphere. The deposition rate of the coatings gradually decreased with increasing N2-to-total (N2 + Ar) flow ratio, RN. The TiVCr alloy and its nitride coatings exhibited a body-centered cubic (BCC) and a face-centered cubic (FCC) crystal structure, respectively. The preferred orientation of the (TiVCr)N coatings changed from (1 1 1) to (2 0 0) with increasing RN. In addition, the microstructure of the nitride coatings was also converted from a columnar structure with void boundaries and rough-faceted surface to a very dense structure with a smooth-domed surface. The grain size of the (TiVCr)N coatings decreased as the RN was increased. Accordingly, the hardness of the (TiVCr)N coatings was enhanced from 4.06 to 18.74 GPa as the RN was increased.

Research highlights▶ The RN is an important parameter for microstructure evolution. ▶ The deposited coatings possessed a simple solid-solution structure. ▶ At RN = 10%, the microstructure evolves through an evolutionary overgrowth mechanism. ▶ As the RN increased to 50%, the recrystallization and restructuring occurred. ▶ The hardness of the (TiVCr)N coatings could achieve 18.74 GPa.