Effect of Film Thickness on the Structural and Tribo-Mechanical Properties of Reactive Sputtered Molybdenum Nitride Thin Films
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Date
2022-06-05
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Publisher
Metallurgical and Materials Engineering Association of Metallurgical Engineers of Serbia AMES
Abstract
The current study aims to examine the impact of nitrogen content and film
thickness on the structural and tribo-mechanical characteristics of reactive sputtered
MoN thin films. Molybdenum nitride thin films with thicknesses ranging from 0.2 to
1.25 m have been applied to steel and silicon substrates for this purpose, with various
amounts of controlled atmosphere (Ar+N2). Then, the films are characterized using
XRD (X-ray diffraction), EDX (energy dispersive X-ray analysis), SEM (scanning
electron microscopy), FTIR (Fourier-transform infrared spectroscopy), and
nanoindentation. The residual stress was measured using the Stoney formula. Results
show that a high compressive residual stress of -5.7 GPa is present in the film with a 0.3
μm thickness and gradually decreases with increasing film thickness. Above 1 µm of
film thickness, there is no change in the density of the MoN films. Also, the coating
hardness and Young’s modulus vary between 9.5 and 35 GPa, and 266 and 320 GPa,
respectively, depending on nitrogen content and film thickness. Lastly, the friction of
the MoN thin films is estimated to be around 0.55, which proves that the oxide is being
slowly removed.
Description
The current study aims to examine the impact of nitrogen content and film
thickness on the structural and tribo-mechanical characteristics of reactive sputtered
MoN thin films. Molybdenum nitride thin films with thicknesses ranging from 0.2 to
1.25 m have been applied to steel and silicon substrates for this purpose, with various
amounts of controlled atmosphere (Ar+N2). Then, the films are characterized using
XRD (X-ray diffraction), EDX (energy dispersive X-ray analysis), SEM (scanning
electron microscopy), FTIR (Fourier-transform infrared spectroscopy), and
nanoindentation. The residual stress was measured using the Stoney formula. Results
show that a high compressive residual stress of -5.7 GPa is present in the film with a 0.3
μm thickness and gradually decreases with increasing film thickness. Above 1 µm of
film thickness, there is no change in the density of the MoN films. Also, the coating
hardness and Young’s modulus vary between 9.5 and 35 GPa, and 266 and 320 GPa,
respectively, depending on nitrogen content and film thickness. Lastly, the friction of
the MoN thin films is estimated to be around 0.55, which proves that the oxide is being
slowly removed.