Abstract:
Several hydro-machinery components such as
impellers of the submersible pump and turbine blades
generally suffer from slurry erosion during their operation.
High-velocity oxy-fuel (HVOF)-sprayed coatings are
promising materials to prevent such components from
slurry erosion. Moreover, polytetrafluoroethylene (PTFE)
is a well-accepted hydrophobic material, which has several
attractive properties such as chemical inertness and considerable thermal stability. Therefore, PTFE coating has
been explored as a topcoat for a HVOF-sprayed WC-10Co4Cr coating, with an aim to enhance the performance of the
latter and analyzed with different slurry erosion conditions.
A slurry erosion test rig was used for experimentation, and
the effect of four different erosion parameters, namely
average particle size, slurry concentration, impact angle,
and velocity of jet, was investigated. A comparative study
between PTFE-modified HVOF-sprayed coating and the
standalone HVOF-sprayed coating was also done with
respect to slurry erosion behavior and hydrophobicity. The
overall results indicate that the slurry erosion of the HVOFsprayed coated SS 316 steel got enhanced after modification by PTFE topcoat. Furthermore, the topcoat of PTFE on
HVOF-sprayed coating resulted in a remarkable improvement in hydrophobicity, showing a superhydrophobic
behavior, which might have also provided a better slurry
erosion resistance to the HVOF-sprayed steel.
