Application of the plasma surface sintering conditions in the synthesis of ReBx–Ti targets employed for hard films deposition in magnetron sputtering technique

Abstract

Preparation of a ternary ReBx–Ti compound within a single magnetron target, forming a plasma surface sintering (PSS) conditions, were investigated. An ionized‑neon pressure of 40 Pa induced sintering power pulses (Ei) with energies of up to 3.1 kJ, which resulted in a low-porosity rhenium boride (3.2%) structure within a solid titanium matrix (ReBx–Ti). The prepared targets showed promising resistance to high temperatures (5.45 mm2/s of thermal diffusivity), after the PSS process at a temperature above 2100 °C. These as-surface-sintered magnetron targets were further used in gas injection magnetron sputtering to obtain Re–B–Ti films characterized by an enhanced deposition rate (120 nm/min). Quantitative analysis of these films revealed that the B/Re ratio was in deficit in comparison to the stoichiometry of as-prepared cathode materials. A multiple-chemical-bond state showed the occurrence of ReB, TiB, BB, TiTi, TiO, and BO phases, of which TiB2 and ReB2 were dominant, forming therefore a glass-like structure. All gathered data indicated a maximum Vickers microhardness value (36.4 GPa), emphasizing the valuable mechanical response of the deposited Re–B–Ti films, as well as the retaining of their good self-passivation effect, attributed by the oxide phases.