Deposition of TiN/TiAlN multilayers by plasma-activated EB-PVD:tailored microstructure by jumping beam technology

Plasma-activated electron beam-physical vapor deposition(EB-PVD)was used for depositing nitride multilayer coatings in this work.Different from the conventional coating methods,the multilayers were obtained by manipulating electron beam(EB)to jump between two different evaporation sources alternately with variable frequencies(jumping beam technology).The plasma activation was generated by a hollow cathode plasma unit.The deposition process was demonstrated by means of tailoring TiN/TiAlN multilayers with different modulation periods(M1:26.5 nm,M2:80.0 nm,M3:6.0 nm,M4:4.0 nm).The microstructure and hardness of the multilayer coatings were comparatively studied with TiN and TiAlN singlelayer coatings.The columnar structure of the coatings(TiN,TiAlN,M1,M2)is replaced by a glassy-like microstructure when the modulation period decreases to less than 10 nm(M3,M4).Simultaneously,superlattice growth occurs.With the decrease of modulation period,both the hardness and the plastic deformation resistance(H~3/E~2,H-hardness and E-elastic modulus)increase.M4coating exhibits the maximum hardness of(49.6±2.7)GPa and the maximum plastic deformation resistance of~0.74 GPa.