This document summarizes a research investigation into the corrosion resistance of nickel-based coatings. The researcher was able to deposit electroless nickel coatings containing silicon carbide particles onto mild steel substrates. Corrosion testing showed that coatings with higher silicon carbide content experienced lower corrosion rates compared to uncoated steel. The coatings provided an effective barrier against corrosion. Future work could explore different substrate materials, heat treatments, corrosion testing conditions, and multilayer coatings to further improve corrosion resistance.

1. AN INVESTIGATION INTO THE
CORROSION RESISTANCE OF NICKEL
BASED COATINGS
Oludolapo George (40062886)
Postgraduate Student
Advanced Materials Engineering
Edinburgh Napier University
Supervisor – Dr. Neil Shearer
Academic Year – 2016

2. RESEARCH(1)
 Some of the greatest structures around today, the Eiffel tower, the
statue of liberty, and the London tower bridge, are either made of
steel or contain steel.
 Pure iron steel’s precursor fuelled the industrial revolution starting
in 1750, enabling the manufacture of various equipment used in
factories and rail transport.
 Steel is one of the most commonly used engineering materials
today.
 Steel has a variety of excellent mechanical properties, such as
strength, toughness, ductility and dent resistance. Amongst its
other properties is also easily formed, welded and manufactured.
 Steel is used in the healthcare sector, in industry it is used for
electricity transmission towers, subsea natural gas pipelines, ships,
tanker trucks, machine tools and military weapons, the list is
endless and nearly everything around us is either made of steel or
manufactured by equipment made of steel.
 However, unfortunately one major problem or disadvantage
associated with steel is its susceptibility to rusting as a result of
“corrosion”.

3. RESEARCH(2)
 Corrosion can be defined as the unintentional, irreversible,
chemical, frequently electrochemical reaction between a
material, and its surrounding environment, which results in
changes and the deterioration of the properties of the
material.
 Replacement or repair of corrosion damaged equipment is
the largest maintenance requirement for industry.
 Why steel and other metals corrode?
The production of almost all metals (and engineering
components made of metals) involves adding energy to the
system. As a result of this uphill thermodynamic struggle, the
metal has a strong driving force to revert back to its native,
low energy oxide state. This return to the native oxide state is
what is called corrosion and even though it is inevitable,
substantial barriers (corrosion control methods) can be
used to slow down the progression of corrosion.

4. RESEARCH(3)
Corrosion control methods include:
 Altering the metal by alloying, that is for example, using a more highly alloyed and expensive
material such as stainless steel rather than plain carbon or low alloy steel
 Applying surface coatings e.g. thin layers of organic coatings (paints, lacquers, varnishes),
metallic coatings (copper, nickel, chromium, zinc), or inorganic coatings (glasses and
ceramics)
 Changing the environment by desiccation or the use of inhibitors
 Controlling the electrochemical potential of the substrate by the application of cathodic or
anodic currents, that is, cathodic protection (CP) and anodic protection (AP)
 Heat treatments.

5. Experimental Procedure
 Electroless Nickel (EN) Deposition
 Mild Steel Substrate
 EN deposition process
 SiC particle (2, 6, & 8 g/l)
 EN co-deposition of SiC
1
 Corrosion Testing
 BS EN ISO 11130 (Alternate Immersion
Testing)
3
 SEM and EDSAnalysis
 Coating thickness
 Deposition of
particles
2

6. Experimental Results
 Based on my experiments, was I able to achieve a thin layer nickel coating?
 Was I able to co-deposit ceramic particles within my coatings?
 Was I able to analyse the morphology of the coatings using the SEM and EDS ?
 Was I able to corrode my samples and analyse them after the corrosion
immersion test?

7. Electroless Nickel Results
 Significant increase in the weight of sample after EN deposition process.
 The results show that there is significant reduction in coating thickness
with an increase in SiC ceramic particle loading in the bath.
 Appearance of sample after deposition process.

8. Weight Loss & Corrosion Rate Results
Corrosion rate (CR) =
(𝜟w × 𝑲)
(𝝆 × 𝑨 × 𝑻)
𝜟w = Weight loss in gram
A = Exposed surface area of sample
𝝆 = Density of mild steel
T = Duration of exposure
K = Constant for unit conversion

9. Immersion corrosion test Results
 The results of immersion test are as
expected, weight loss calculations showed
that the loadings with the highest amounts
of SiC content were more corrosion
resistant than mild steel and Ni-P
substrates.
 SiC ceramic particles within the nickel
coating, provide a barrier layer for
protection of the mild steel samples against
the corrosive NaCl solution.
 The corrosion rate of samples with SiC
particles showed lower rates of
degradation when compared to the plain
mild steel and Ni-P coated sample.

10. Conclusions
 The application of near uniform coatings can be accomplished with electroless nickel
deposition.
 Results showed that the corrosion rates of ceramic reinforced Nickel coatings
provide better corrosion resistance when compared to uncoated mild steel
substrates, Ni-P-SiC composite coatings had the best resistance to corrosion at SiC
loadings of 6 g/l and 8 g/l.

11. Possible Future Work
 Use of different substrate materials in the electroless nickel deposition process.
 Heat treatments could be carried out to improve adhesion between coating and
substrate
 Use of different corrosive test solutions, in the immersion test experiment.
 Longer immersion test duration and day to day documentation of weight difference of
samples, to show corrosion rate.
 Research into the corrosion behaviours of multilayer diamond-like carbon coatings
and their influence on deposition periods and corrosive medium, with incorporation of
SiC or Cu particles to each layer, with the aim of improving the corrosion, wear and
electrical behaviours of the substrate material.

12. THANK YOU