Thermal and mechanical properties of (W,Zr)B2-z coatings deposited by RF magnetron sputtering method

Magnetron sputtered WB2 coatings doped with 8, 11 and 16 at.% zirconium were analysed using energy dispersive spectroscopy, X-ray diffraction and nanoindentation under the load of 4, 7 and 10 mN. It has been observed that these coatings crystallize in the α-AlB2 and ω-W2B5 prototype structure. Phenomenon responsible for this is an increase of the zirconium content which causes an increase in the ω-W2B5 phase. All the deposited coatings have a hardness of about 45 GPa while Young's modulus drops down from 497 to 480 GPa with increasing zirconium content. Coatings without doping and doped with 16 at.% zirconium were annealed at 650 °C and subjected to cyclic thermal loads using a maximum temperature 600 °C and cooling with a compressed air. It has been observed that addition of zirconium improved coatings phase stability. •Zr doped WB2 coatings deposited by RF magnetron sputtering•Zr doping improve crack resistance and Young's modulus of WB2 coatings•Coatings hardness above 40 GPa even after annealing and thermal shocks