Fracture properties of α– and k–Al2O3 hard coatings deposited by chemical vapor deposition

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Abstract

Although α– and κ–Al 2 O 3 hard coatings deposited by chemical vapor deposition are well established in the metal-cutting industry for their ability to increase the performance and lifetime of cutting tools, the literature on their fracture properties is scarce. Thus, within this study, the mi-crostructure and mechanical properties of α– and κ–Al 2 O 3 coatings were investigated and compared to each other. X-ray diffraction and scanning electron microscopy combined with electron backscatter diffraction showed that both coatings exhibited a fiber texture, where the α–Al 2 O 3 coating displayed a (0001) texture and the κ–Al 2 O 3 coating a (001) texture with a certain (013) contribution. Higher hardness and Young’s modulus values of 31.0 ± 0.9 GPa and 474.6 ± 12.5 GPa, respectively, were ob-tained for the α–Al 2 O 3 coating, compared to 24.2 ± 0.8 GPa and 356.8 ± 7.9 GPa for κ–Al 2 O 3 . While the α–Al 2 O 3 coating exhibited a higher fracture stress of 8.1 ± 0.3 GPa (compared to 6.4 ± 0.6 GPa for κ–Al 2 O 3 ), the κ–Al 2 O 3 coating showed a higher fracture toughness of 4.4 ± 0.3 MPa*m 1/2 (compared to 3.2 ± 0.3 MPa*m 1/2 for alpha).

Original languageEnglish
Article number1359
Number of pages10
JournalCoatings
Volume11.2021
Issue number11
DOIs
Publication statusPublished - 4 Nov 2021

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Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

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