Electrochemical printing:in situcharacterization using an electrochemical quartz crystal microbalance

Abstract

Electrochemical printing (EcP) is a multi-scale freeform fabrication method employing localized electrodeposition beneath a rastering microjet print head flying microns above the deposition substrate. As a result of the confined geometry and unusual electrochemical configuration, conventional in situ diagnostics are difficult to implement. We show that EcP microfabrication on an electrochemical quartz crystal microbalance (EQCM) allows in situ characterization of the electrochemical processes occurring locally beneath the microjet print head and over large patterned areas where corrosion occurs. Copper deposition experiments show the microjet print head can produce extraordinary mass transfer limiting currents (in excess of 10 A cm−2). The current efficiency for EcP patterning of copper on gold is limited by oxygen reduction at low applied currents and by hydrogen evolution at high currents. Nonetheless, the maximum current efficiency is >90% over two orders of magnitude change in microjet flow rate; the limiting current varies five-fold over the same flow rates. Calibration of the EQCM local sensitivity factors allows characterization and control of corrosion rates when printing extended patterns.

Development of a maskless electrochemical texturing method

“…Also, the quantity of electrolyte used to machine each workpiece is quite small and the whole apparatus is relatively simple. Nelson and Schwartz (2005) have developed a process called electrochemical printing (ECP), which has some similarities but electrolytically deposits material rather than removing it. Furthermore, the process occurs at a single location rather than over a large number of areas in parallel.…”

Analytical and Computational Scaling Relationships for the Coupled Phenomena that Control Local Bipolar Electrochemical Behavior

“…19 Secondary current distribution simulations were performed in the 2D axisymmetric computational domain in Figure 1b. All secondary current simulations used a microjet nozzle with dimensions of r i = 100 μm and r o = 335 μm.…”

Some innovative surface texturing techniques for tribological purposes

“…The first technique, called photochemical texturing (PCT), has been widely used and described in the literature, but this work presents some alternatives that reduce equipment and Chemical conversion coatings [34] Catalyst or precursor deposition + CVD [36,37] Patterned autocatalytic plating [38,39] Patterned anodising [34] Patterned electrodeposition [32] Electrolytic coatings Chemical deposition coatings Patterned precipitation coating [39] Chemical Processes* Inkjet for deposition of wear-resistant patterns [40,46,47] FIB for deposition of wear-resistant patterns [42] Patterned curing [41] Patterned deposition of organic coatings (painting) [86][87][88][89][90][91][92][93][94][95] Electrochemical printing [33] Spin coating of micro and nano particles [44] Physical Deposition…”