Mass transport effects during electropolishing of iron in phosphoric-sulfuric acid

Datta, Madhav; Vega, LF; Romankiw, L. T.; Duby, Paul

doi:10.1016/0013-4686(92)87086-f

Cited by 23 publications

(14 citation statements)

References 17 publications

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“…Data on the diffusion coefficient of Al 3+ in phosphoric acid is unavailable to our knowledge. Instead, we followed the reasoning of Datta et al 48 and assumed, that the diffusion coefficient of metal ions in concentrated electrolytes depends mainly on viscosity and electrolyte temperature and not on the type of metal ion. Thus, we used a least squares fit of diffusion coefficient and viscosity data determined for Cu • C. Finally, we estimated the characteristic velocity in the vicinity of the mask opening from the velocity gradient and the characteristic length via u ∼ ∇uL.…”

Section: Resultsmentioning

confidence: 99%

Through-Mask Electrochemical Micromachining of Aluminum in Phosphoric Acid

Baldhoff

Nock

Marshall

2017

J. Electrochem. Soc.

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Aluminum micro-channels have been machined in phosphoric acid via mass-transfer limited electrochemical dissolution through photoresist masks. The results of shape evolution experiments using a rotating disk electrode are presented in terms of the dimensions, shape profile and uniformity of the machined micro-channels. The influences of applied potential, cumulative passed charge and hydrodynamic conditions on the shape evolution process are discussed. Experimental results are compared with a shape evolution model assuming the rate of aluminum removal is solely controlled by diffusive mass transfer. The degree of agreement between experimental and simulated results depends mainly on the hydrodynamic conditions in the electrochemical cell and indicates a shift from purely diffusive to mixed convective-diffusive mass transfer. Through-Mask Electrochemical Micromachining (TMEMM) is an unconventional machining process, in which a metal substrate is made the anode in an electrochemical cell and thereby dissolved.1,2 Localized material removal is achieved by covering the substrate with an insulating mask. The use of common photolithography processes for the creation of the mask enables the fabrication of micrometer-sized structures. Thereby, TMEMM can be used in two ways to fabricate microfluidic devices: firstly, cavities and channels can be machined into the substrate surface and secondly, through-holes and slits can be machined into metal foils or shims.1 Compared to classical wet chemical and dry etching processes, TMEMM offers higher rates of material removal, better control of surface finish, more selective machining of substrates and enhanced process safety. [3][4][5] In addition, combining photolithography with electrochemical dissolution processes is expected to enable the fabrication of a large number of microfluidic devices in parallel and at low cost. 6Aluminum is widely used as a construction material for the manufacture of microfluidic devices such as micro-heat exchangers, 7 microreactors 8 and micro-fuel cells. 9 Other areas of interest are the fabrication of intricate parts in optical, electronic, automotive and aerospace systems. 10,11 Its chief advantages compared to other materials used in these fields are its high thermal conductivity, low electrical resistivity, easy machinability and low density. In addition, it is possible to modify the surface structure of aluminum substrates via the formation of highly ordered, porous oxide films along the surface. 12,13 It has been demonstrated, that these films can be subsequently used to incorporate noble metal catalysts along the surface of micro-channels within a micro-reactor. [14][15][16] Electrochemical dissolution of aluminum in phosphoric acid is known to produce reflective aluminum surfaces with sub-micrometer surface roughness at sufficiently high electrolyte concentration and temperature.17 This property makes it attractive for TMEMM of micrometer-sized structures made from aluminum. The observed leveling and brightening effect is caused by the m...

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Section: Resultsmentioning

confidence: 99%

Through-Mask Electrochemical Micromachining of Aluminum in Phosphoric Acid

Baldhoff

Nock

Marshall

2017

J. Electrochem. Soc.

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“…213 More recent studies of electropolishing are found in Ref. [214][215][216][217][218][219]. Electrochemical machining (ECM) was developed in the 1960s for machining of complex shapes in hard to machine alloys used mostly by the aerospace industry.…”

Section: Electrochemical Engineering Aspects Of Electrodepositionmentioning

confidence: 99%

Electrodeposition Science and Technology in the Last Quarter of the Twentieth Century

Landolt

2002

J. Electrochem. Soc.

126

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“…Furthermore, addition of glycerol into this system was adopted (Datta and Romankiw, 1998;Datta et al, 1991). In this glycerol containing system, the limiting polishing current was found to depend slightly on the flow rate (Datta and Romankiw, 1998) and a concept for minimizing agitation of the electrolyte was proposed to eliminate the cost of pumping concentrated acids (Datta et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

A study of the morphology and optical properties of electro polished steel in the presence of Vitamin-C

Abouzeid¹

2015

Afr. J. Pure Appl. Chem.

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The studies of steel electrochemical polishing Electropolishing (EP) in orthophoshoric acid were performed by potentiodynamic polarization. Electropolishing was conducted in solution containing Vitamin C. Addition of Vitamin C to electropolishing solution results in a lower limiting current. Vitamin C concentration influence on electropolishing process and surface texture (AFM, SEM) and UV-VIS-NIR Spectroscopy was established. The results show that by increasing Vitamin C concentration from 2 × 10 -5 to 5 × 10 -5 M, roughness and reflectance of steel specimens decrease/increase respectively. The opposite trend is seen when the concentration increases to 10 × 10 -5 M. The roughness of steel specimen before electropolishing is 236.7 nm and it will decrease to 140 nm by electropolishing in the presence of 5 × 10 -5 M Vitamin C. A similar trend is also seen in reflection. The SEM study confirms that low and moderate concentration of Vitamin C was effective to enhance levelling and brightness more than higher concentrations.

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Mass transport effects during electropolishing of iron in phosphoric-sulfuric acid

Cited by 23 publications

References 17 publications

Through-Mask Electrochemical Micromachining of Aluminum in Phosphoric Acid

Through-Mask Electrochemical Micromachining of Aluminum in Phosphoric Acid

Electrodeposition Science and Technology in the Last Quarter of the Twentieth Century

A study of the morphology and optical properties of electro polished steel in the presence of Vitamin-C

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