The effects of nitrogen bonding on hardness of AIN/CrN multilayer hard coatings.
AIN/CrN multilayer hard coatings with various bilayer thicknesses were fabricated by a reactive sputtering process. The microstructural and mechanical characterizations of multilayer coatings were investigated through transmission electron microscope (TEM) observations and the hardness measurements by nano indentation. In particular, the variation of chemical bonding states of the bilayer nitrides was elucidated by near edge X-ray absorption fine structure (NEXAFS) spectroscopy. Many broken nitrogen bonds were formed by decreasing the bilayer thickness of AIN/CrN multilayer coatings. Existence of optimum AIN/CrN multilayer coatings thickness for maximum hardness could be explained by the competition of softening by the formation of broken nitrogen bonds and strengthening induced by decreasing bilayer thickness.
Nano Analysis Center Korea Institute of Science and Technology, Hawolkok-dong, Seongbuk-ku, Seoul 130-650, Korea.
Sang-Won
SW
Yoon
Jong-Hyun
JH
Seo
Keun-Hwa
KH
Chae
Jong-Keuk
JK
Park
Jong-Han
JH
Song
Vickram
V
Jayaram
Kon-Bae
KB
Lee
Tae-Yeon
TY
Seong
Hoon-Kwon
Jae-Pyoung
JP
Ahn