The localized electrochemical deposition (LECD) process has been used to fabricate 3D microproducts. We combine the LECD process with a real-time 3D image feedback distance control system to improve the quality and conformational design complexity of 3D microproducts. Analyses of microproducts show that the main factor for designing complex 3D microproducts is the deposition direction angle that can be controlled in a 2D fabrication method. The deposition direction angle was the angle between the normal direction of the substrate surface and deposition direction. The normal direction of the substrate surface was determined 0°.We investigate two methods to improve the deposition direction angle in this study. The first method makes use of a new type of micro anode with asymmetric tip. By using this asymmetric micro anode, the deposition direction angle is found to range between −12.0° and 107.9°. This range is only to display the performance of the anode that proposed in this study. The second method is to redesign the moving mechanism and increase actuators and axes. By employing these two methods, we demonstrate high quality fabrication of two types of microstructures: helical springs with low pitch angle and inverted tripods.

A novel microsensor, consisting of crossed Cu micropillars coated with ZnO nanorods, was fabricated by electrochemical methods for detecting gas in a small space. The Cu micropillars (80 μm diameter, 10 mm long) were prepared by microanode-guided electroplating (MAGE) on the periphery of a square copper pad (dimensions 5.0 mm × 5.0 mm × 1.0 mm). The micropillars were electrochemically coated with a 500 nm thick layer of ZnO nanorods deposited from a bath containing 2.0 mM zinc chloride and H2O2 varying in 5, 10, 15, and 20 mM. Two ZnO-coated pillars were crossed to form a microsensor by approaching the Cu pads below, which was adhered to an alumina substrate with silver paste and connected to conducting wires for measurement. The morphology of the coating of ZnO nanorods, which was found to be determined by the concentration of H2O2 in the bath, influenced the gas sensing. The morphology of the coating was characterized by scanning electron microscopy; the structural analysis was carried out by X-ray diffraction and high-resolution transmission electron microscopy (HRTEM); the surface analysis was carried out by X-ray photoelectron spectroscopy; and the defects were determined with photoluminescence (PL) spectra. We thus investigated the effect of the morphology of the coating on the sensing properties by introducing a stream of gases varying in CO/air ratios to understand the sensing mechanism of the microsensor.

The purpose of this research was to develop a new micro-anode-guided electroplating (MAGE) system equipped by an image-guided positioning controller, to fabricate two-dimensional microstructures. From real-time image, the relative positions of the micro-anode and the microstructures tip can be located and maintained. When the relative position is adjusted, the deposition direction of the microstructures can be controllable and microstructures with different geometries can be fabricated.During past decades, the fabrications of 3D microstructures and nanostructures have been attracting attention because of their applications in biosensors, gas sensors, thermal couples, and 3D integrated chips. Many processes have been proposed to produce 3D micro-and nanostructures, such as Lithographie Galvanoformung Abformung (LIGA), 1 localized electrochemical deposition (LECD), 2 mask projection micro-stereo lithography, 3 track-etch method, and laser-assisted chemical vapor deposition (LCVD). 4 Among these techniques, LECD has the advantages of being an inexpensive, mask-less, low-power, and easy-to-design technique. 5-12 Furthermore, LECD can be applied to multiple materials such as metals, metal alloys, piezoelectric material, conducting polymers, and semiconductors. 13 New methods have been proposed to improve the performance of LECD; these include micro-anode-guided electroplating (MAGE), 14 deposition-detection-withdrawal (DDW) control method, 15 and realtime image-guided micro-anode electroplating system. MAGE has demonstrated that the micro-anode can be controlled to move in either continuous or intermittent mode to guide the progress of Nielectroplating; 14 hence, it influences the surface morphology of the electroplated microstructures. Although the resulting microstructures are less porous, their surface is rough and nodular. To improve the surface quality of microstructures by employing the MAGE process, C.S. Lin proposed a DDW control method, 15 which could prevent the possible contact between the microstructures and the micro-anode. However, the resulting surfaces are not uniform because the deposition rate is not constant as it is affected by electric field that is applied on surface of the microstructures. 16 Moreover, the variation of the electric field owing to the variation in the gap between the anode and microstructure cannot be controlled by employing the MAGE process or DDW control method. To address all these problems, a MAGE system with real-time image processing was proposed to create a steady electric field on the microstructure surface proposed. 17 This system stabilizes the distance between the anode and the microstructure on the basis of measurements based on from real-time imaging, ensuring that the formed column structures are smooth with no pores, uniform, and straight. Moreover, the diameter of the microstructure can be controlled by adjusting different parameters, such as applied voltage and the distance between the anode and the microstructure. 18 Most previous studies 13-21 mainly focused on...

Amorphous metals have wide applications, including those in various transducer and sensor devices, because of their extraordinary physical and chemical characteristics, excellent mechanical properties, and corrosion resistance. However, their intrinsic ultrahigh strength and frangibility limit their manufacturing. Herein, a microanode-guided electroplating (MAGE) method is introduced to fabricate three-dimensional microhelices of amorphous Ni–Cr alloys. In MAGE, a super-high strength electrical field (∼105 V m–1) was established by charging a few volts across a tiny electrode gap (approximately 100 μm). The current density of MAGE was 2 orders of magnitude higher than that of traditional thin-film electrochemical coating that undergoes kinetic control processes, favoring the amorphous phases. The morphology, composition, and physical properties of the micro Ni–Cr devices were also investigated, revealing the outstanding reduced Young’s modulus (165 GPa), hardness (8.21 GPa), and high-temperature Joule heating stability up to 1200 °C.

Cu-Zn alloy micropillars were fabricated by a potentiostatic localized electrochemical deposition (LECD) process. This process was carried out via micro-anode-guided electroplating in a pyrophosphate bath at a constant negative potential in the range −1.85 to −2.05 V. Different products were produced, depending on the initial inter-electrode gap employed. Thus, at an initial gap of 40 μm, the process afforded micropillars with a single α-brass crystal phase and at.% Zn contents in the range 17.20-32.01%. A reduction in the initial gap to 30 μm resulted in varied micropillar crystal phases (α, β, and β + β') with at.% Zn contents in the range 37.12-68.94. The simulation commercial software COMSOL 5.2 was employed to correlate the asymmetric distribution of the electric field to the experimental parameters and pillar characteristics. The resultant data was then used to delineate the dependence of the field strength on the crystal phase, composition, growth rate, and micropillar diameters. Finally, a potentiodynamic cathodic polarization study was employed to elucidate the mechanism for the fabrication of the Cu-Zn alloy micropillars via potentiostatic LECD.