Influence of Al content on the mechanical properties and thermal stability in protective and oxidation atmospheres of Zr–Cr–Al–N coatings

Abstract

Tools have been used under very high temperature in recent decades. Therefore, coatings on tools are required to be thermally stable and excellent in oxidation-resistance. The introduction of Al into nitride coatings was considered as an effective way to improve the coating oxidation-resistance and thermal stability. Quaternary Zr-Cr-Al-N coatings were deposited with increasing Al contents by d.c. reactive magnetron sputtering. The coatings were annealed at 800 and 900 o C for 1h in Ar + H 2 atmosphere and exposed at 700 o C for 2h and 1200 o C for 1h in air, respectively. The hardness, Young's modulus, adhesive/cohesive strength and residual stress of as-deposited and annealed coatings were characterized by nanoindentation, scratch test and curvature measurement method. The results showed that the coating hardness and Young's

Effect of hafnium contaminant present in zirconium targets on sputter deposited ZrN thin films

“…It is noted that ZrN thin film (0.9 at.% Hf contaminant) is majorly oxidized at 773 K, which is confirmed by the predominant presence of peaks related to its oxide ZrO 2 . Such behavior ratifies its low oxidation resistance in ~773 K, as previously discussed in literature [12].…”

“…In this context, studies show a recurring content of hafnium in Zr and ZrN thin films deposited by RMS [9,10]. Due to the very low contamination (Hf < 1 at.%), detection of this chemical element is imperceptible by traditional characterization techniques, as EPMA [11] and EDS [12]. Even when Hf atoms are identified in ZrN matrix, their presence is still considered negligible [13,14].…”

Evolution of the functional properties of titanium–silver thin films for biomedical applications: Influence of in-vacuum annealing

“…Such trend, promoted by annealing, is certainly related with the Ag solid solution effect and the microstructure evolution (Fig. 4a) [39,48,51]. On the contrary, the samples with higher Ag content (zone II) exhibit higher Y g' values, particularly at 500 ºC (137 and 107…”

“…Given the low concentration of silver in the two representative samples of zone I (0.04 at.% and 0.2 at.%), the energy supplied by the thermal treatments promotes Ag diffusion into the Ti structure, resulting in lattice defects and hence microstrains [18,41]. a h b y h α-Ti phase increases results in some grain refinement (grain boundaries reduction), as discussed above, and leads to what might be called an enhanced solid solution hardening effect [39,48]. This effect also promotes more well-defined microstructures as demonstrated by the SEM analysis, Fig.…”

“…moduli [46,48,51]. Despite that effect, the main reason to explain the obtained values should be related with the crystallization of Ti-Ag intermetallic phases.…”