Role of Selected Organic Additives in Sulfate-Based Electroplating Baths for Copper Electrodeposition Toward Additive Manufacturing.

Precise control of copper electrodeposition is essential for electrochemical additive manufacturing based on layer-by-layer growth. In this work, the influence of selected organic additives, nicotinic acid, benzotriazole, thiourea and urea in sulfate-based electroplating baths was investigated with respect to their applicability in electrodeposition-driven 3D printing. Linear sweep voltammetry (LSV) was used to analyze the electrochemical behavior of Cu(II) reduction, while copper layers were deposited under potentiostatic conditions in a flow-assisted system (potential controlled conditions). The obtained deposits were characterized by SEM/EDS and quantitative measurements of layer thickness and dendrite height. The results show that the additives strongly affect both deposition kinetics and the morphology of electrodeposited layers. Benzotriazole acts as a strong inhibitor, producing fine-grained structures but reducing deposition efficiency and not fully suppressing vertical growth instabilities. Thiourea leads to highly unstable deposition with excessive dendritic growth and increased impurity incorporation. Nicotinic acid enables relatively thick deposits with moderate dendrite formation within an optimal concentration range. In contrast, urea provides the most stable growth, yielding uniform layers with minimal dendritic development and high copper purity. The dendrite height-to-layer thickness ratio proved to be an effective descriptor of electrodeposition growth stability. These findings highlight the critical role of additive selection in optimizing electroplating baths for electrochemical 3D printing applications.