TY - JOUR

T1 - Microstructure and mechanical properties of CVD TiN/TiBN multilayer coatings

AU - Kainz, Christina

AU - Schalk, Nina

AU - Tkadletz, Michael

AU - Mitterer, Christian

AU - Czettl, Christoph

PY - 2019/7/25

Y1 - 2019/7/25

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=85065517358&partnerID=8YFLogxK

U2 - 10.1016/j.surfcoat.2019.04.086

DO - 10.1016/j.surfcoat.2019.04.086

M3 - Article

VL - 370.2019

SP - 311

EP - 319

JO - Surface & coatings technology

JF - Surface & coatings technology

SN - 0257-8972

IS - July

ER -