Thermal stability and mechanical properties of sputtered (Hf,Ta,V,W,Zr)-diborides

Hard and electrically conductive multicomponent diboride-based films with high thermal stability

“…Furthermore, the peaks obtained after annealing to 1300 • C are wider compared to as-deposited samples, but actually narrower compared to those obtained after annealing to 1100 • C. Note that a similar peak broadening resulting from annealing to the same temperature of 1300 • C was reported for (HfTaVWZr)-diborides in Ref. [21].…”

“…The entropy calculated for these materials using their exact compositions Hf 8 Zr 4 Ti 4 Ta 4 Y 5 B 60 C 9 and Hf 10 Zr 4 Ti 4 Ta 4 Ho 5 B 58 C 9 is − 1.57R and − 1.54R, respectively, per metal atom in their crystalline part. This categorizes these materials as high-entropy metal sublattice diborides (HESB) [21]. Similar entropic stabilization of ternary solid solutions of YB 2 with HfB 2 , TaB 2 or TiB 2 is discussed in Ref.…”

“…Unlike binary diborides, there are only a few works dealing with high-entropy diboride films. Thermally stable solid solution (Hf,Ta,V,W,Zr)B 2 has been successfully deposited via magnetron sputtering with hardness over 40 GPa and thermal stability up to 1200 • C. However, an orthorhombic (V,W)B phase formed at higher temperatures [21]. In another work the comparison of (Zr,Ti,Hf, V,Ta)B 2 with (ZrTi)B 2 and ZrB 2 revealed its higher hardness in the as-deposited state but also higher affinity to oxygen when the temperature exceeds 1100 • C [22].…”

Recent Progress on High-Entropy Films Deposited by Magnetron Sputtering

“…Their microstructural and mechanical properties remain stable even at high temperatures. Kirnbauer et al [98] reported on the thermal stability and mechanical properties of (HfTaVWZr)B 2 film when changing the substrate bias. A single phase AlB 2 structure was formed that remained unchanged even after vacuum annealing at 1300 • C. However, by increasing the temperature to 1400 • C, an additional (V,W)B phase was formed with (Hf,Ta,Zr)B 2 as a matrix (Figure 7).…”

Investigation of the Effect of Supersonic Flow of Dissociated Nitrogen on ZrB2–HfB2–SiC Ceramics Doped with 10 vol.% Carbon Nanotubes

“…One way to improve material properties is to use solid solutions based on these phases, instead of individual zirconium or hafnium diborides, including so-called high-entropic compositions [ 21 , 22 , 23 ]. In this aspect, in [ 24 ] it was found that the introduction of HfB 2 improved the free sintering at temperatures of 2100–2150 °C of ZrB 2 –SiC ceramic material (in the presence of B 4 C and MoSi 2 ); in this case, a solid solution (Zr,Hf)B 2 is formed.…”