Berlin 2024 – scientific programme
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DS: Fachverband Dünne Schichten
DS 6: Thin Film Properties I
DS 6.10: Talk
Tuesday, March 19, 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