406
M. Malathi et al.
Table 5 Weight loss comparison of NiP medium P + SiC non-heat treated & heat treated with that
of chrome-plated piston rings
S. No. Specimen name
Initial weight (gm) Final weight (gm) Weight loss (mg)
1.
NiP medium P + SiC
100 g/lt non-heat
treated
0.34030
0.33809
2.21
2.
NiP medium P + SiC
100 g/lt heat treated
0.316089
0.31320
2.88
3.
NiP medium P + SiC
50 g/lt non-heat
treated
0.31282
0.31053
2.29
4.
NiP medium P + SiC
50 g/lt heat treated
0.31192
0.30969
2.23
5.
NiP medium P + SiC
5 g/lt non-heat treated
0.34494
0.34196
2.98
6.
NiP medium P + SiC
5 g/lt heat treated
0.34593
0.34369
1.45
7.
Base material without
any coating
0.39764
0.39399
3.65
8.
Chrome-plated piston
ring
0.3165
0.315
1.5
4 Conclusions
In this study, a novel method plate and bumper method was attempt for co-deposit
ultrafine composite SiC dispersed in electrolytic bath onto the piston rings. From the
detailed investigations, the following conclusions can be drawn.
(i) Micro-structure and XRD measurement show co-deposition of ultrafine SiC
particles size was homogenously co-deposited with nickel phosphorus onto
the piston ring.
(ii) Hardness of the composite-coated piston ring is observed to be max with
increase in concentrations of SiC and dunking speed. Hardness of the NiP-SiC
composite coated is in the range of 700–1015 HV0.05 g which is comparable
to chrome-plated hardness (800 HV0.1). Chrome plating is a regular plating
process in vogue for innumerable engine piston ring applications today.
(iii) The wear and corrosion results of the NiP composite-coated piston ring is
comparable with that of existing chrome plating process which is in current
application.