Microstructure and mechanical properties of CVD TiN/TiBN multilayer coatings

Christina Kainz, Nina Schalk, Michael Tkadletz, Christian Mitterer, Christoph Czettl

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25 Citations (Scopus)

Abstract

Application of a multilayered coating architecture based on two alternating hard materials provides a strategy to enhance the mechanical properties of hard coatings for the metal cutting industry. Within this work, the mechanical behavior of CVD TiN/TiBN multilayer coatings was correlated with their microstructure and compared to the respective single-layers. Multilayers with different bilayer periods (1400, 800, 300 and 200 nm)were prepared in an industrial-scale thermal CVD plant by alternate variation of the feed gas composition. Complementary X-ray diffraction, Raman spectroscopy and transmission electron microscopy investigations confirmed a dominating face-centered cubic TiN structure, accompanied by hexagonal TiB 2 and amorphous TiB in the B containing coatings. The addition of B and a decreasing bilayer period resulted in a decreasing grain size and increasing hardness. Micromechanical bending tests revealed an increase of strength and fracture toughness with addition of B and increasing layer number. While the highest strength was observed in a TiBN single-layered coating, the multilayered TiN/TiBN with a bilayer period of 200 nm was the hardest and at the same time toughest of the investigated coatings.

Original languageEnglish
Pages (from-to)311-319
Number of pages9
JournalSurface & coatings technology
Volume370.2019
Issue numberJuly
DOIs
Publication statusPublished - 25 Jul 2019

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