Interfacial stability and diffusion barrier ability of Ti_1−xZr_xN coatings by pulsed laser thermal shock

Highlights: • TiZrN coatings were prepared using TiZr targets with different Zr ratios. • Thermal shock test was conducted to TiZrN coatings by a Nd-YAG pulsed laser ablation system. • Lattice parameter and hardness of coatings increased as Zr ratio increased. • Degradation of coatings by laser ablation decreased according to increase of Zr ratio. • Atomic diffusion at interface by laser ablation was suppressed by solid solution effects. - Abstract: Interfacial characteristics and diffusion behavior of Ti_1−xZr_xN coatings under thermomechanical stress were investigated, in terms of morphologies and depth profiles, after pulsed laser ablation. TiZrN coatings were deposited on SUS304 substrates, using TiZr compound targets with Ti:Zr wt.% ratio of 90:10, 70:30, and 50:50. XRD patterns showed the same growth orientations of TiN and ZrN as (1 1 1), (2 0 0), and (2 2 0) in all coating specimens. The lattice parameters and the microhardness increased through solid solution with the substitutions of Zr to the Ti sites. Spalling of the coating layer was observed in the specimen of 10% wt.% Zr ratio after laser ablation. Delamination was suppressed as the substitution of Zr increased, and it could be attributed to the formation of ZrN which can promote heat transfer in the coating layer faster than TiN. SIMS depth profiles revealed that the diffusion distance of the coating (Ti, Zr) and the substrate (Cr, Fe) atoms decreased, due to diffusion path reduction by the solid solution effects