Effect of number of layers on the toughness of TiN/TiC multilayer coatings

Abstract

The structure and mechanical properties of titanium nitride/titanium carbide multilayer coatings on H13 hot work tool steel were investigated. All coatings were deposited by the pulsed–DC plasma–assisted chemical vapour deposition. Field emission scanning electron microscopy was used to study the crystalline structure of coatings. Indentation tests were carried out by atomic force microscopy and the Vickers hardness test. The objective of this paper is to determine mechanical properties such as the hardness, the elastic modulus and the toughness of different coatings. Increasing the number of layers in multilayer coatings increased the elastic modulus, the hardness and the toughness with respect to the single–layer coatings. Superior mechanical properties such as high hardness (26.7 GPa), high elastic modulus (327.6 GPa) and high toughness (17.7 MPa.m1/2) were related to multilayer coatings with 10 layers due to the compressive residual stress.