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DS: Fachverband Dünne Schichten

DS 6: Thin Film Properties I

DS 6.10: Vortrag

Dienstag, 19. März 2024, 12:30–12:45, A 060

Detailed Microstructure and the Influence of Post-Treatment on CVD TiAlN Wear-Resistant Coatings — •Monica Mead¹, Olof Bäcke², Dirk Stiens³, and Mats Halvarsson² — ¹Institute for Materials Science, University of Stuttgart, Germany — ²Department of Physics, Chalmers University of Technology, Gothenburg, Sweden — ³Walter AG, Tübingen, Germany

The suitable properties of cubic TiAlN have led to its importance as wear-resistant coating for cutting tools. Preparation by chemical vapour deposition (CVD) has enabled deposition with Al contents above 90 at.% while limiting formation of undesired hexagonal TiAlN. Despite intensive research on the growth of CVD TiAlN coatings, there is no comprehensive understanding of the growth mechanism and intricate microstructure. In addition, research on the effect of blasting on the stress state of wear-resistant coatings is considerable, while the effect on the microstructure is less well studied.

In this work, the microstructure of nano-lamellar low-pressure CVD TiAlN coatings on cemented carbide substrates and the influence of blasting is investigated by scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM) and transmission Kikuchi diffraction (TKD). Two distinct morphologies are observed and connected to specific grain orientations. Furthermore, the proposed growth mechanism suggests an influence of the detailed microstructure on the surface reaction kinetics leading to varying Al/Ti ratios. Blast-treatment of the hard TiAlN coatings introduces plastic deformation, where an influence of the grain orientation is observed.

Keywords: TiAlN; LPCVD; texture; blasting