Influence of interfacial structure on the mechanical and thermal properties of CrAlN/ZrN multilayer coatings

• CrAlN/ZrN_9 and _5 multilayer coatings with bilayer periods of 9 to 5 nm exhibit nonepitaxial and local epitaxial interfaces.
• This transformation of nonepitaxial to local epitaxial interfaces results in an increased hardness and adhesion strength.
• CrAlN/ZrN_5 coating exhibits better thermal stability and thermo-mechanical properties.
• CrAlN/ZrN multilayer coatings show an oxidation behavior of layer by layer, and CrAlN/ZrN_5 has better oxidation resistance.

Multilayer architecture based on CrAlN coatings to improve their properties attracts great attention. Here, the structure, mechanical and thermal properties of CrAlN/ZrN multilayer coatings with bilayer periods of ~ 5 and 9 nm are investigated. Decreasing bilayer period of CrAlN/ZrN coating from 9 to 5 nm results in a transformation of interfacial structure between CrAlN and ZrN sublayers from nonepitaxial to local epitaxial interfaces, and thereby has a positive effect on the hardness, adhesion strength, thermal stability and oxidation resistance. Additionally, a layer by layer oxidation behavior of CrAlN/ZrN coatings leads to the formation of lamellar oxide scale.

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