Research Progress of Maskless Localized Electrodeposition Technology Coupled with Ultrasonic Field and Magnetic Field

Maskless localized electrodeposition (MLED) is a micro electrochemical-additive manufacture (ECAM) technology based on electrochemical deposition. By introducing the concept of additive manufacturing (AM), MLED can fabricate metal based 2D and 2.5D films or coatings, as well as 3D metal microstructures, in a layer by layer manner. It has attracted increasing attention in electronic information, high end equipment, precision instruments, micro device manufacturing, surface strengthening, and surface modification. In recent years, ultrasonic and magnetic fields have been introduced into the MLED process to improve deposition performance. When these external fields are coupled with the electrodeposition field, deposition defects can be reduced, deposition efficiency can be improved, surface quality can be enhanced, and micro or nanocrystalline structures can be refined. These effects provide an effective approach for fabricating 3D metal microstructures, metal coatings, and metal matrix composite coatings with improved physical and mechanical properties. They also help achieve the "AM＋" effect and meet specific functional requirements. This paper reviews the process principles, technical characteristics, research progress, and application outcomes of MLED coupled with ultrasonic and magnetic fields. The main effects of ultrasonic and magnetic fields on the MLED process are summarized, and the future development of MLED coupled with multiple energy fields is discussed.