The Corrosion Resistance of Nickel Electrocomposite Coating Containing BaFe12O19 Particles

Electroplating composite coating is an effective method to prepare composite coating through the codeposition of metallic, nonmetallic, or polymer particles with metal to improve properties such as corrosion resistance, hardness, and wear performance. This paper reports the synthesis of a novel Ni-BaFe12O19 magnetic nanocomposite coating exhibiting improved corrosion resistance. In the present paper, BaFe12O19 particles were synthesized by a single-step solution combustion method and characterized for phase, particle size, and morphology. These particles were incorporated in a nickel metal matrix, and the properties of the coatings like nanohardness and corrosion resistance were investigated. The coating microstructure was also studied using field emission scanning electron microscope. A Vickers hardness of 777？HV was exhibited by Ni-BaFe12O19, and plain Ni coating exhibited a hardness of 517？HV. The Ni-BaFe12O19 composite coating exhibited improved corrosion resistance compared to plain Ni coating with an value of 0.034？μA/cm2 compared to 0.361？μA/cm2 for plain Ni. The Ni-BaFe12O19 coating also exhibited higher charge transfer and polarization resistance compared to plain Ni coating. 1. Introduction In recent years, there is an increased interest in the synthesis and properties of particle reinforced metal matrix nanocomposite coatings with grain size of both matrix and dispersed particles less than 100？nm [1]. Particle-reinforced metal matrix composite (MMC) coatings have been widely used in various engineering applications due to their excellent mechanical, wear, and corrosion resistant properties compared to their components [2]. In composite materials, the metal matrix properties are modified by the addition of various insoluble substances like hard oxides ( , , , , and ); carbides (SiC and WC); diamond or solid lubricants (graphite, , or PTFE) [2, 3]. Electrocodeposition is a coating protective technique which consists of introducing homogeneously dispersing inert particles of a different material in the metal matrix; this two-phase coating improves corrosion, wear, and mechanical resistance. The improvement of these properties depends on the combination of both particles and metal matrix. This method has the following advantages like low cost, low temperature and single-step process without additional thermal treatment [4]. The application of magnetic particles in electrodeposited composite coatings is less explored. Barium ferrite thin film media are attractive candidates for high-density overcoat free magnetic recording due to their large