聚焦射流三维电沉积加工技术

To meet the increasingly needs of applications, the favorable additive manufacturing of three-dimensional (3D) metal microstructures and microparts is a hot and frontier issue in the metal 3D printing field. The jet electrodeposition technique has been respected to be used as an effective metal additive micromanufacturing method, but fails to realize that objective due to its some unsolved problems. A novel jet electrodeposition technique, called focused jet 3D-electrodeposition, is presented by employing a special focused jet in order to enhance its 3D additive micro-manufacturing capacity in this program. The main investigations will focuse on the fundamental theories and key technologies of this novel technique. Specificly, mass transfer characteristics, current distribution characteristics and electrodeposition behaviours of the proposed technique will be studied with the focused jets formed under some typical formation conditions, and then some fundamental issues on electrodeposition selectivity and shape accuracy, morphology, microstructures, properties of the 3D metal parts are evaluated. Further more, some key functions describing the distribution characteristics of mass transfer rate, current density and selectivity, etc., are developed. On the other hand, several key technologies concerning detection of characteristic information of mass transfer as well as measurement of polarization curves during the focused jet electrodeposition are researched in this program. Finally, the fundamental sytem of this novel technique will be constructed based on the theroretical and experimental investigations. The expectation that an advanced and applicable metal 3D additive micro-manufacturing technique will be developed is hoped to realized after this program.

三维(3D)金属微结构与零件的高效增材制造，需求旺盛，是3D金属打印领域的关注热点与研究前沿。面向金属微增材制造，射流电沉积技术虽盛有工艺潜能，但困于技术瓶颈制约而至今仍力不从心。本项目深入问题根源，引入特殊射流载体，提出一种金属微增材制造新技术--聚焦射流3D电沉积，并深入开展其基础理论与关键技术等方面的研究。重点探索多种典型形成或存在条件下(如气/液-液组合，圆/方形射流等)的聚焦射流阴极面特征区的传质与电场分布及电沉积行为特性、以及基于它们的沉积选择性、3D微制件成形精度、形貌与组织结构特征、机械力学性能等基础理论问题，建立传质速率、电流密度、选择性评价等的函数式；着力突破聚焦射流限域微区传质特征信息获取、极化曲线测量等关键技术，理论与实验研究相结合，构建聚焦射流3D电沉积的基础理论与关键技术体系，进而奠定其发展与工程应用基础，以期为我国金属3D微结构与零件的增材制造提供先进适用技术

三维(3D)金属微结构与零件的高效增材制造，需求旺盛，是3D金属打印领域的关注热点与研究前沿。射流电沉积有诸多金属微增材制造的工艺潜能，但因受瓶颈性难题制约而力不从心。本项目定力于问题本质，引入特殊射流载体，提出一种面向金属微增材制造的新技术—聚焦射流3D电沉积，并深入开展了基础理论与关键技术等方面的研究。重点探索气-液组合圆形聚焦射流阴极面特征区的传质与电场分布以及电沉积行为特性、以及基于它们的沉积选择性、3D微制件成形精度、形貌与组织结构特征等基础理论问题，构建了电流密度分布、射流直径等数学关系式，研究突破了聚焦射流限域微区内传质特征信息获取技术，研制出射流电沉积微增材制造系统，加工出复杂形状微增材制件。研究表明：(1) 电解液射流在外包裹流体氮气的粘性剪切作用下，在优化条件下能获得直径比喷口更小、射程长、断面流速分布均匀的聚焦射流，但流速空间分布与压差、原始射流流速大小、聚焦几何结构等参数密切相关；(2) 聚焦射流电解液液束的断面流速（距离基底1mm出的流速分布）均匀且聚焦射流的滞留区域较小、流速较大，聚焦射流可使电流密度更集中，且外围电绝缘气体对杂散电流起到了一部分屏蔽作用；加工间隙越小，电流密度分布的定域性越好，周围杂散电流越小；射流流速与气体压强差对阴极电场分布的影响不明显；(3) 聚焦射流射束直径及液跃内环直径均随沉积柱体高度的增长而变化；随着高度的增大，射束直径在低外围压强范围内逐渐变小，然后变大，而液跃内环直径逐渐减小，但外围压强太大时，液束离散化而丧失了加工工具能力；(4) 聚焦射流电沉积制件的空间定域性明显优于初始成膜期间的定域性，稳定沉积过程具有非常高的成形精度与一致性；(5) 聚焦射流电沉积能制造出超长径比（大于）或复杂形状的金属构件，且表面质量高、成形一致性好。本项目的研究显示：聚焦射流电沉积技术在金属3D微结构与零件的增材制造方面具有很大的发展潜力。