TY - JOUR

T1 - Microstructure, mechanical and thermo-physical properties of CVD TiCxN1-x coatings on cemented carbide substrates grown with C2H6 as C feeding precursor

AU - Kainz, Christina

AU - Schalk, Nina

AU - Tkadletz, Michael

AU - Winkler, Markus

AU - Czettl, Christoph

N1 - Publisher Copyright: © 2020 Elsevier B.V.

PY - 2020/7/25

Y1 - 2020/7/25

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=85085268457&partnerID=8YFLogxK

U2 - 10.1016/j.surfcoat.2020.125868

DO - 10.1016/j.surfcoat.2020.125868

M3 - Article

VL - 394.2020

JO - Surface & coatings technology

JF - Surface & coatings technology

SN - 0257-8972

IS - 25 July

M1 - 125868

ER -