TITLE:
Solid Particle Erosion Behaviour of TiN Coating on AISI 4140 Steel
AUTHORS:
J. R. Laguna-Camacho, J. E. Escalante-Martínez, R. Cruz-Vicencio, J. V. Méndez-Méndez, I. Arzate-Vázquez, I. Hernández-Romero, M. Vite-Torres
KEYWORDS:
Erosion Wear; PVD Nitride Coating, TiN; Wear Mechanisms
JOURNAL NAME:
Journal of Surface Engineered Materials and Advanced Technology,
Vol.4 No.1,
January
16,
2014
ABSTRACT: In this
study, the performance against erosive wear of PVD TiN (titanium nitride)
coating was evaluated using an erosion test rig similar to that described in
the standard ASTM G76-95. This coating normally has various industrial
applications such as tapping, drilling, dry machining and punching. Angular
silicon carbide (SiC) was used as an abrasive particle with a grain size of 350-450 μm. Erosion tests
were carried out using different incident angles, 30°, 45°, 60° and 90° with a
particle velocity of 24 ± 2 m/s, an abrasive flow rate of 0.7 ± 0.5 g/min, and the test temperature was between 35°C and 40°C. The particle
velocity and the abrasive flow rate were low in all of the tests to reduce the
interaction between the incident and the rebounding particles in the system.
The surfaces were examined with a scanning electron microscope (SEM) to characterize
the erosive damage. The wear mechanisms identified were brittle fracture characterized by
radial cracks on the surface by multiple impact and a few pits at 30°, while a few cracks and the
formation of craters in random positions were observed at angles near or at 90°.
Elliptical scars were observed at 30° and 45°, which are a characteristic feature when the specimens are impacted at
low-incident angles (α ≤ 45°) whereas a roughly circular scar was seen at 60° and 90°. In addition, roughness variations were analyzed using atomic force
microscopy (AFM), before and after the erosion tests, and the results exhibited
an increase in the roughness as the TiN samples were impacted at angles near or
at 90°.