Improving the adhesion of CrN coatings on TC4 alloy substrates by discharge current modulation in magnetron sputtering

Abstract

The study reports the formation of multilayer coatings of CrN with variable gradient modulus on TC4 substrate by varying the discharge current of the hot filament in magnetron sputtering. Results show that multilayer CrN/TC4 has a higher critical failure load (63.4 N > 29.7 N), lower maximum tensile stress (103.8 GPa < 134.3 GPa), and a higher ratio of plastic to elastic deformation work (W_p/W_e, 2.11 > 1.58) than a single layer CrN/TC4. This indicates that the energy absorption ability of the coating/substrate before failure can be improved by increasing the loose energy-absorbing sublayer, thus improving the coating/substrate adhesion. Notably, the wear rate of both multilayer and single-layer coatings is in the order of 10⁻¹⁶ m³/(N·m), demonstrating their excellent wear resistance. Structural engineering enables the application of multilayer CrN coatings on low-modulus and high-strength alloy substrates, such as TC4.

HIGHLIGHTS

A dense-porous multilayer coating obtained by varying the filament discharge currents.

The modulus difference between the multilayer CrN and TC4 reduced.

The maximum tensile stress appeared at the interface of the Cr and CrN layers.

The multilayer CrN/TC4 with high W_p/W_e and absorption ability of deformation work.

The multilayer CrN/TC4 was with high adhesion and excellent wear resistance.