400
M. Malathi et al.
Fig. 4 a Coating depth trend without SiC, b coating depth trend with 5 g/lt of SiC, c coating depth
trend with 50 g/lt of SiC, d coating depth trend with 100gms/lt of SiC
The piston rings composite plated with SiC ceramic particle at current density 3
amps/dm
2 for 60 min plating time (with various concentrations of SiC) were subjected
to heat treatment at 300 °C for 2 h. The coating characterization for hardness, microstructure, XRD, wear and corrosion.
3 Results and Discussion
3.1 Micro-Vickers Hardness
The micro-Vickers hardness of both the rings (with and without heat treatment)
measured in Matsuzawa hardness tester using 50 gm load is given below. Table 3 gives
the hardness readings of the rings with various dunking cycles and SiC concentration.
The hardness on the electroplated composite coating has increased with an
increase in concentration of ceramic particle (SiC) and dunking speed. The increase in
hardness after heat treatment is due to precipitation of nickel phosphide intermetallics
like Ni3P [2].