**Author details**

corrosion resistance of the coatings (30 mV potential shift). Ref. [70] reported MoS2 particles to lower friction the coefficient of Ni–W matrix and enhance its tribological properties.

Electroplated nickel composite/nanocomposite coatings find applications in machining and finishing of tools requiring excellent corrosion and wear resistance, low friction, and high thermal stability. Wear, friction, and corrosion pose a serious threat to machine lifespan, energy consumption, and performance. These phenomena also compromise the safety of the person‐ nel where the machine is used. Therefore, engineers prefer machines that have long lifespan, save energy, and have better performance throughout its service life. These machines or tools are made of lighter and cost-effective materials such as aluminium and steel, to enhance their quality; materials harder and chemically stable than them are used as coatings to protect them from surface degradation. Nickel, nickel alloy, and composite/nanocomposite coatings are

Ni–SiC nanocomposite coatings are used to offer wear protection of aluminium-made engine pistons in automotive industry [70]. These parts operate under high temperatures and wear conditions. Other candidates that perform similar function of lining of cylinders in aluminium

Electrodeposited Ni/diamond coatings have found applications in grinding and cutting tools, such as precision cutting wheels for dicing semiconducting silicon plates [71]. These also include nickel alloy composite coatings such as Ni–W reinforced with diamond nanoparticles. These coatings exhibit high hardness, excellent wear resistance, and elevated thermal stability.

Ni–PTFE composite coatings find use in precise mechanical parts [17]. These possess selflubricating properties and are convenient for applications that require low friction. Other suitable coatings to perform similar functions are Ni–CNT, MoS2, graphite, Si3N4, Ni–B, and

This chapter outlines the fabrication of nickel composite/nanocomposite coatings, their properties, and applications. Due to the excellent properties exhibited by these coatings such as high hardness, excellent corrosion resistance and wear resistance, self-lubricating proper‐ ties, and high thermal stability, the coatings have a good potential to replace chromium-based coatings. Their mechanism of co-deposition and optimization of process parameters need to be understand well to produce better coatings with improved surface properties. This understanding will also enable extension of their applications in the future to serve as

alternatives for other coatings fabricated by cost and energy-intensive processes.

perfect candidates for improving the quality of these materials.

BN composite coatings. They also exhibit high oxidation resistance.

engines are Ni–Al2O3, TiO2, WC, Cr2O3, etc. [71].

**7. Applications**

224 Electrodeposition of Composite Materials

**8. Conclusion**

Nicholus Malatji and Patricia A.I. Popoola\*

\*Address all correspondence to: popoolaapi@tut.ac.za

Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria, South Africa
