TY - JOUR

T1 - Structural evolution of oxygen on the surface of TiAlN: Ab initio molecular dynamics simulations

AU - Guo, Fangyu

AU - Wang, Jianchuan

AU - Du, Yong

AU - Holec, David

AU - Ou, Pengfei

AU - Zhou, Hao

AU - Chen, Li

AU - Kong, Yi

PY - 2018/11/22

Y1 - 2018/11/22

N2 - We have employed ab initio molecular dynamics simulations to study the oxidation behavior of TiAlN hard coatings as a function of Al content and temperature. Results show that for TiAlN with a low Al content (Ti 0.75 Al 0.25 N), Ti atoms can always bond with O atoms, while Al atoms bond with O only at a higher temperature. For Ti 0.5 Al 0.5 N, both Al and Ti can bond with O atoms, irrespective of temperature. Through analyzing the displacement height of O-bonded metal atoms, we suggest that titanium oxide nucleates at the outermost layer of Ti 0.75 Al 0.25 N while the outermost layer after Ti 0.5 Al 0.5 N is exposed to oxygen is aluminum oxide. Our simulation results predict, in agreement with experiment, that Ti 0.5 Al 0.5 N has superior oxidation resistance in comparison with Ti 0.75 Al 0.25 N. This study provides an atomistic insight to the initial stage of the oxidation process, which is else difficult to observe experimentally.

AB - We have employed ab initio molecular dynamics simulations to study the oxidation behavior of TiAlN hard coatings as a function of Al content and temperature. Results show that for TiAlN with a low Al content (Ti 0.75 Al 0.25 N), Ti atoms can always bond with O atoms, while Al atoms bond with O only at a higher temperature. For Ti 0.5 Al 0.5 N, both Al and Ti can bond with O atoms, irrespective of temperature. Through analyzing the displacement height of O-bonded metal atoms, we suggest that titanium oxide nucleates at the outermost layer of Ti 0.75 Al 0.25 N while the outermost layer after Ti 0.5 Al 0.5 N is exposed to oxygen is aluminum oxide. Our simulation results predict, in agreement with experiment, that Ti 0.5 Al 0.5 N has superior oxidation resistance in comparison with Ti 0.75 Al 0.25 N. This study provides an atomistic insight to the initial stage of the oxidation process, which is else difficult to observe experimentally.

UR - http://www.scopus.com/inward/record.url?scp=85056988024&partnerID=8YFLogxK

U2 - 10.1016/j.apsusc.2018.11.158

DO - 10.1016/j.apsusc.2018.11.158

M3 - Article

VL - 470.2019

SP - 520

EP - 525

JO - Applied surface science

JF - Applied surface science

SN - 0169-4332

IS - March

ER -