Mapping the mechanical properties in nitride coatings at the nanometer scale

Zaoli Zhang, Zhuo Chen, David Holec, Christian Liebscher, Nikola Koutná, Matthias Bartosik, Yong Hui Zheng, Gerhard Dehm, Paul Heinz Mayrhofer

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

Abstract

We report on a multilayered structure comprising of rock-salt (rs) structured CrN layers of constant thickness and AlN layers of varying thicknesses, which surprisingly enables the growth of metastable zinc-blende (zb) AlN layers for certain layer-thickness combinations. The multilayer exhibits an atomic and electronic structure gradient as revealed using advanced electron microscopy and electron spectroscopy. Gradient structures are also accompanied by a modulation of the chemical compositions. A combined experimental analysis based on valence electrons and inner shell electrons allowed mapping the mechanical properties of the multilayer at the nanometer scale and further unveiled the effect of oxygen impurities on the bulk modulus. We found that the presence of oxygen impurities causes a remarkable reduction of the bulk modulus of rs-CrN while having no significant effect on the bulk modulus of the stable wurtzite structure wz-AlN layers. The findings are unambiguously validated by theoretical calculations using density functional theory.

OriginalspracheEnglisch
Seiten (von - bis)343-353
Seitenumfang11
FachzeitschriftActa materialia
Jahrgang194.2020
Ausgabenummer1 August
Frühes Online-Datum15 Mai 2020
DOIs
PublikationsstatusVeröffentlicht - 1 Aug. 2020

Bibliographische Notiz

Funding Information:
The author (Z. Z.) acknowledges very helpful discussion with Paul Thomas (Gatan Company, USA) about EELS quantification of oxygen. Z.C. acknowledges the financial support from the China Scholarship Council (CSC, 201608120053 ). Herwig Felber at the Erich Schmid Institute of Materials Sciences is gratefully acknowledged for his helps with the TEM sample preparation. DH and MB acknowledge the financial support of the Austrian Science Fund (FWF): P30341-N36 .

Publisher Copyright:
© 2020 Acta Materialia Inc.

Dieses zitieren