TY - JOUR
T1 - Study on the crack resistance of CrBN composite coatings via nano-indentation and scratch tests
AU - Wang, Qianzhi
AU - Zhou, Fei
AU - Callisti, Mauro
AU - Polcar, Tomas
AU - Kong, Jizhou
AU - Yan, Jiwang
N1 - Funding Information:
This work has been initiated by a Japan-China joint research project and partially supported by a research grant from Keio Leading-edge Laboratory of Science and Technology (KLL) in Keio University. In addition, this work has been supported by National Natural Science Foundation of China (Grant No. 51375231), Research Fund for Doctoral Program of Higher Education (Grant No. 20133218110030), Scientific Research Foundation for the Introduced Talent, Nanjing University of Aeronautics and Astronautics (Grant No. 1005-YAH16043) and Project Funded by Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD). We would like to acknowledge them for their financial support.
Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2017
Y1 - 2017
N2 - Crack resistance of CrBN coatings in relation to B concentration was investigated via nano-indentation and scratch tests. A nano-composite structure consisting of CrN nano-grains embedded in amorphous BN (a-BN) matrix was observed by transmission electron microscope (TEM). XRD and XPS analyses revealed a decrease of crystallinity in coatings as B content increased from 16.4 to 27.2 at.%, which led to a hardness decrease from 28.9 GPa to 23.6 GPa. All CrBN coatings, regardless of composition, prevented radial cracks due to superior mechanical properties (H/E ≥ 0.077). However, owing to high compressive stress (3.27–4.74 GPa), circumferential cracks were found along indent edge, and the number of circumferential cracks was proportional to B concentration. Meanwhile, the critical load of initiating crack dropped from 17.9 to 13.4 N when B concentration raised from 12.8 to 22.2 at.%. The results of nano-indentation and scratch tests indicated that the crack resistance of CrBN coatings became poor when the B doping content increased. In here, the CrBN coating with 12.8 at.% B exhibited the best crack resistance.
AB - Crack resistance of CrBN coatings in relation to B concentration was investigated via nano-indentation and scratch tests. A nano-composite structure consisting of CrN nano-grains embedded in amorphous BN (a-BN) matrix was observed by transmission electron microscope (TEM). XRD and XPS analyses revealed a decrease of crystallinity in coatings as B content increased from 16.4 to 27.2 at.%, which led to a hardness decrease from 28.9 GPa to 23.6 GPa. All CrBN coatings, regardless of composition, prevented radial cracks due to superior mechanical properties (H/E ≥ 0.077). However, owing to high compressive stress (3.27–4.74 GPa), circumferential cracks were found along indent edge, and the number of circumferential cracks was proportional to B concentration. Meanwhile, the critical load of initiating crack dropped from 17.9 to 13.4 N when B concentration raised from 12.8 to 22.2 at.%. The results of nano-indentation and scratch tests indicated that the crack resistance of CrBN coatings became poor when the B doping content increased. In here, the CrBN coating with 12.8 at.% B exhibited the best crack resistance.
KW - Circumferential crack
KW - CrBN
KW - Nano-indentation
KW - Residual stress
KW - Scratch
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U2 - 10.1016/j.jallcom.2017.03.105
DO - 10.1016/j.jallcom.2017.03.105
M3 - Article
AN - SCOPUS:85015019204
SN - 0925-8388
VL - 708
SP - 1103
EP - 1109
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
ER -