Publication details

Effect of bonding structure on hardness and fracture resistance of W-B-C coatings with varying B/W ratio

Authors

MIRZAEI Saeed ALISHAHI Mostafa SOUČEK Pavel ZÁBRANSKÝ Lukáš BURŠÍKOVÁ Vilma STUPAVSKÁ Monika PEŘINA Vratislav BALÁZSI Katalin CZIGÁNY Zsolt VAŠINA Petr

Type Article in Periodical
Magazine / Source Surface & coatings technology
MU Faculty or unit

Faculty of Science

Citation
Web Full Text
Doi http://dx.doi.org/10.1016/j.surfcoat.2018.12.007
Keywords Magnetron sputtering Protective coating Nanocomposite Hardness
Description Low ductility and brittle deformation behaviors are major drawbacks of currently used commercial hard ceramic-based protective coatings. Recent ab-initio calculations revealed that the coexistence of metallic, boride and carbide bonds in a nanolaminate structure of crystalline W2BC system provides a combination of high hardness together with moderate ductility. The present paper deals with coatings containing W, B and C with different compositions and investigates the effect of the boron to tungsten ratio (B/W) on the structural and mechanical properties of W-B-C coatings prepared by pulsed-DC magnetron sputtering at a moderate temperature. Coatings with low B/W were deposited in a nanocomposite structure, whereas coatings with high B/W ratios were near-amorphous. The structure of the coatings was not a decisive factor in determining their mechanical properties. These were, however, directly correlated with the chemical bonds present. All the coatings exhibited high fracture resistance. These properties together with good adhesion to cemented tungsten carbides make W-B-C coatings promising candidates for the future protective coatings of tools which undergo large deformation in their working cycle.
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