Microstructure, mechanical and thermo-physical properties of CVD TiCxN1-x coatings on cemented carbide substrates grown with C2H6 as C feeding precursor

Christina Kainz, Nina Schalk, Michael Tkadletz, Markus Winkler, Christoph Czettl

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

5 Zitate (Scopus)

Abstract

The established industrial processes used for the growth of TiC xN 1-x coatings by chemical vapor deposition (CVD) suffer from substantial limitations, either in regard of brittle phase formation or restriction in the C/(C + N) ratio. Using the alternative C precursor C 2H 6 allows to overcome these issues. Thus, within this work, the microstructure, phase composition, micro-mechanical and thermo-physical properties of CVD TiC xN 1-x coatings grown with C 2H 6 were investigated. Through adjustment of the C 2H 6 and N 2 flow in the feed gas, the C/(C + N) ratio in the coatings was varied between pure TiN and TiC 0.80N 0.20. All coatings are characterized by a single-phase face centered cubic structure. The 〈110〉 fiber texture present in all coatings becomes more pronounced with increasing C content. None of the investigated coatings showed thermal cracks on the surface. The thermal conductivity decreases with addition of C from 45 ± 5 W/mK in TiN to 32 ± 3 W/mK in all ternary TiC xN 1-x coatings. TiC 0.47N 0.53 exhibits the highest hardness (30.0 ± 1.4 GPa), while TiC 0.63N 0.36 turned out as the stiffest coating with a Young's modulus of 576 ± 23 GPa. The fracture stress σ F and toughness K IC are superior in coatings with moderate C and N content, with TiC 0.63N 0.37 being the strongest (σ F = 7.7 ± 0.4 GPa) and TiC 0.47N 0.53 (K IC = 4.4 ± 0.3 MPa m 1/2) the toughest within this series. Coatings with moderate to high C content were found to exhibit a microstructure provoking a lower thermal conductivity and improved mechanical properties compared to those with a low C/(C + N) ratio.

OriginalspracheEnglisch
Aufsatznummer125868
Seitenumfang7
FachzeitschriftSurface & coatings technology
Jahrgang394.2020
Ausgabenummer25 July
Frühes Online-Datum3 Mai 2020
DOIs
PublikationsstatusVeröffentlicht - 25 Juli 2020

Bibliographische Notiz

Funding Information:
The authors want to thank Marianne Penoy, MSc. (CERATIZIT Luxembourg s.àr.l.) for the GDOES measurements. Further, we are grateful to Martina Dienstleder (Austrian Centre for Electron Microscopy and Nanoanalysis) for FIB/SEM work. The financial support by the Austrian Federal Ministry for Digital and Economic Affairs and the National Foundation for Research, Technology and Development is gratefully acknowledged.

Publisher Copyright:
© 2020 Elsevier B.V.

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