TITLE:
Erosion and Toughening Mechanisms of Electroless Ni-P-Nano-NiTi Composite Coatings on API X100 Steel under Single Particle Impact
AUTHORS:
Marissa MacLean, Zoheir Farhat, George Jarjoura, Eman Fayyad, Aboubakr Abdullah, Mohammad Hassan
KEYWORDS:
Electroless Ni-P Composite Coating, Superelastic NiTi, Single Particle Impact, Erosion Mechanisms, Toughening
JOURNAL NAME:
Journal of Surface Engineered Materials and Advanced Technology,
Vol.9 No.4,
October
22,
2019
ABSTRACT: The addition of superelastic NiTi to electroless Ni-P coating has been found
to toughen the otherwise brittle coatings in static loading conditions, though
its effect on erosion behaviour has not
yet been explored. In the present study, spherical WC-Co erodent particles were
used in single particle impact testing of
Ni-P-nano-NiTi composite coatings on API X100 steel substrates at two average
velocities—35 m/s and 52 m/s. Erosion tests were performed at impact angles of 30°, 45°, 60°, and 90°. The effect of NiTi concentration in the coating was also examined.
Through examination of the impact craters
and material response at various impact conditions, it was found that the
presence of superelastic NiTi in the brittle Ni-P matrix hindered the
propagation of cracks and provided a barrier to crack growth. The following
toughening mechanisms were identified: crack bridging and deflection,
micro-cracking, and transformation toughening.