Abstract
Maskless localized electrodeposition (MLED) is a micro–additive manufacturing (micro‐AM) technique in which metals are deposited electrochemically without the use of a physical mask. Through controlled, incremental material growth, the technique can produce two‐dimensional and quasi–three‐dimensional metallic films and coatings, as well as fully three‐dimensional metal microstructures. Its potential applications cover electronic devices, advanced equipment, precision instruments, microsystem fabrication, and localized surface enhancement. A major direction in recent MLED research is the introduction of external physical fields, especially high‐speed jet flow and laser irradiation. These external fields can improve ionic transport and electrochemical reaction behavior, thereby reducing deposition defects, accelerating material growth, producing smoother surfaces, and promoting grain refinement at micro‐ and nanometer scales. Consequently, external field–assisted MLED offers a promising approach to fabricating three‐dimensional metallic features, functional coatings, and metal‐matrix composite coatings with tailored physical and mechanical characteristics, supporting both AM integration and application‐specific performance. This review discusses the working mechanisms, process characteristics, and recent developments of jet‐assisted MLED (Jet‐MLED) and laser‐assisted MLED (Laser‐MLED) for producing metal microstructures and coatings. The respective contributions of jet flow and laser irradiation are analyzed, the capabilities of Jet‐MLED and Laser‐MLED are compared, and the major limitations of both approaches are identified. Remaining scientific questions and possible developments involving multiple coupled energy fields are also considered. These discussions provide guidance for improving deposit quality and material properties. In particular, integrating MLED with appropriately controlled external fields may enhance manufacturing precision and process adaptability, allowing the technique to address increasingly complex tasks in micro‐ and nano‐electrochemical AM. Systematic investigation of Jet‐MLED and Laser‐MLED is therefore essential for the continued development of this field.