Atom probe tomography investigation of 3D nanoscale compositional variations in CVD TiAlN nanolamella coatings
Journal article, 2021

The cubic (Ti1−xAlx)Ny (TiAlN) phase with a nanolamella structure, synthesized via low pressure chemical vapour deposition (LPCVD), has been widely used in wear-resistant coatings during the latest years. The nanolamella structured TiAlN coatings contain periodic and epitaxially grown Ti-rich [denoted as Ti(Al)N] and Al-rich [denoted as Al(Ti)N] lamellae. However, the chemical compositions of these nano-structures have not been fully revealed. In this study, the microstructure of the nanolamella TiAlN coating was studied using scanning and transmission electron microscopy (SEM and TEM), and the chemical content was investigated using atom probe tomography (APT) that provides three-dimensional composition data with good accuracy and a spatial resolution down to the nanometer scale. It was found that over- and under-stoichiometries of N exist for the Ti(Al)N and the Al(Ti)N lamellae, respectively. According to the previous simulation results, such over- and under-stoichiometries are due to metal (Al and Ti) and N vacancies, respectively. The Al(Ti)N lamellae have a chemical formula of (Ti0.12Al0.88)N0.90, and have 10% N vacancies. The Ti(Al)N lamellae have a chemical formula of (Ti0.70Al0.30)0.97N, and have 3% metal (Al and Ti) vacancies. In addition to the nanolamella structure, compositional variations on a scale of a few nm were found in both types of lamellae. In the Ti-richest volumes, the composition corresponds to (Ti0.72Al0.28)0.88N so a maximum of 12% of metal vacancies exists. In the Al-richest volumes, the composition corresponds to (Ti0.07Al0.93)N0.64 so a maximum of 36% N vacancies exists. In addition, a small amount of Cl (around 0.1 at.%) was found in the coating, which could originate from the incomplete dissociation of chloride precursors during the CVD surface reaction.







Ren Qiu

Chalmers, Physics, Microstructure Physics

Hisham Aboulfadl

Chalmers, Physics, Microstructure Physics

Olof Bäcke

Chalmers, Physics, Microstructure Physics

Dirk Stiens


Hans-Olof Andrén

Chalmers, Physics, Microstructure Physics

Mats Halvarsson

Chalmers, Physics, Microstructure Physics

Surface and Coatings Technology

0257-8972 (ISSN)

Vol. 426 127741

CVD 2.0 - En ny generation av hårda beläggningar

Swedish Foundation for Strategic Research (SSF) (RMA15-0048), 2016-05-01 -- 2021-06-30.

Subject Categories

Inorganic Chemistry

Metallurgy and Metallic Materials

Driving Forces

Sustainable development


Basic sciences


Chalmers Materials Analysis Laboratory

Areas of Advance

Materials Science



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