Fabrication of a micrometer Ni–Cu alloy column coupled with a Cu micro-column for thermal measurement

Abstract

Micrometer Ni-Cu alloy columns have been fabricated by the micro-anode-guided electroplating (MAGE) process in the citrate bath. The surface morphology and chemical composition of the micro-columns were determined by copper concentration in the bath and by the electrical bias of MAGE. When fabricated in a bath of dilute copper (i.e. 4 mM) at lower voltages (e.g. 3.8 and 4.0 V), the alloy micro-columns revealed uniform diameter and smooth appearance. The alloy composition demonstrated an increase in the wt% ratio of Ni/Cu from 75/25, 80/20, 83/17 to 87/13 with increasing electrical bias from 3.8, 4.0, 4.2 to 4.4 V. However, it decreases from 75/25, 57/43 to 47/53 with increasing copper concentration from 4, 8 to 12 mM in the bath. Citrate plays a role in forming complexes with nickel and copper at similar reduction potentials, thus reducing simultaneously to Ni-Cu alloy. The mechanism for fabricating alloy micro-columns could be delineated on the basis of cathodic polarization of the complexes. A couple of micro-columns were fabricated using MAGE in constructing a pure copper micro-column on the top of a Ni/Cu (at 47/53) alloy micro-column. This micro-thermocouple provides a satisfactory measurement with good sensitivity and precision.

Three-Dimensional Amorphous Ni–Cr Alloy Printing by Electrochemical Additive Manufacturing

“…This fact implies that the morphology and the chemical composition of the Ni–Cr alloy microwires made using the MAGE process are determined by the electrical field strength governed by the potential and the interelectrode gap. The optimal strength of the electric field is different and dominated by the system of alloy microwires (such as Ni–Cu and Cu–Zn alloy microwires), which were investigated in our previous works.…”

Mask-Less Electrochemical Additive Manufacturing: A Feasibility Study

“…While some AM processes such as selective laser melting and electron beam melting are capable of producing parts superior to machined parts, they suffer from very high residual stresses due to the complete melting of the material during manufacturing [7]. With the use of micro electrode anode, some earlier studies have demonstrated the capa bility of creating microstructures such as metal pillars through localized electrodeposition (LED) [10][11][12][13][14]. ECAM process is capable of depositing most of the conductive materials including metals, metal alloys, conduct ing polymers, and even some semiconductors [8,9].…”

Finite Element Simulation of Localized Electrochemical Deposition for Maskless Electrochemical Additive Manufacturing

“…Finally, while electrochemical processes have proven their capability in electro plating and electroforming over large areas, localizing the deposi tion remains a challenge. The few studies that have successfully localized depositions are limited to simple structures, such as metal lines and pillars [12][13][14][15][16][17]. Complex 3D structures have not yet been fabricated using this technique.…”