Advanced Insights on the Co-Deposition Mechanisms in Ceramic Particles Reinforced Metal Matrix Composites

Electrodeposited composite coatings are produced by the ability to co-deposit particle reinforcements along with the metal from the galvanic bath suspension. Electro-co-deposition process has been extensively studied and developed to produce a wide range of composite coatings with desired properties. The inherent versatility of this process and the associated materials allows for its implementation across diverse industries—including automotive, electronics, micro-mechanical, and biomedical devices. Despite advancements in electrodeposited composite development, significant gaps remain in understanding the fundamental mechanisms governing particle incorporation and the corresponding microstructural evolution of the metal matrix. This work aims on elucidating the influence of microstructural tuning on the co-deposition mechanisms of ceramic-reinforced metal matrix composites. To understand this role of microstructure, electrolytic copper was co-deposited with alumina nanoparticles on brass substrate under galvanostatic conditions (dc and pulse) in an acidic model bath without additives. Characterization of the electrodeposited composite was performed by scanning electron microscopy (SEM), focused-ion beam (FIB), and X-Ray Diffraction (XRD). The presence of nanoparticles in the electrolyte has shown to influence the nucleation and growth mechanisms of the deposited metal matrix. Nevertheless, a core mechanistic question persists regarding the direction of causality: whether the presence of incorporated particles alters nucleation, or if controlled nucleation and growth facilitates particle incorporation (a 'chicken-and-egg' problem). In this research, an important correlation is observed, where deposits with finer grain microstructures demonstrated significantly higher particle incorporation compared to those with a coarse grain structure, directing at the possible hypothesis based on combined physical and metallurgical influences. [1] J. Fransaer et al 1992 J. Electrochem. Soc. 139 413 [2] Shao, I., et al. "Kinetics of particle co-deposition of nanocomposites." Journal of the Electrochemical Society 149.11 (2002): C610.