Sequential electromachining and electropolishing of metals and the like using modulated electric fields
AssigneeFaraday Technology Marketing Goup, LLC
InventorE. Jennings Taylor
Life of this patent
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Abstract
A surface of an electrolytically dissolvable material, e.g., an electrolytically dissolvable metal, is smoothed by a two-step electrochemical process wherein a the surface to be smoothed and a counterelectrode are contacted with an electrolyte and an electric current is passed between the substrate and counterelectrode, with the substrate as the anode. In a first step relatively large asperities on the substrate are reduced in height by maintaining a macroprofile regime by using a pulsed electric current with short pulses. In a second step, small asperities and the remainder of the large asperities are reduced or removed by maintaining a microprofile regime by using a pulsed current having longer pulses or a direct current.
Claims17
A method for smoothing the surface of an electrodissolvable substrate comprising
- providing an electrodissolvable substrate having a surface with macroasperities, said macroasperities having a height greater than about 100 micrometers;
- providing a counterelectrode;
- interposing an electrolyte between and in contact with said substrate and said counterelectrode;
- and
- passing an electric current between said substrate and said counterelectrode, whereby a Nernst diffusion layer is established at said substrate surface;
- wherein
- in a first step,
- said diffusion layer is maintained at a thickness to produce a macroprofile regime for at least the largest of said macroasperities until said macroasperities have been reduced to a height less than about 100 micrometers thereby being converted into microasperities;
- and
- in a second step,
- said diffusion layer is maintained at a thickness to produce a microprofile regime to reduce the height of said microasperities.
A method for smoothing the surface of an electrodissolvable substrate comprising,
- in a first step,
- providing an electrodissolvable substrate having a surface with macroasperities, said macroasperities having a height greater than about 100 micrometers;
- providing a counterelectrode;
- interposing an electrolyte between and in contact with said substrate and said counterelectrode;
- and
- converting said macroasperities into microasperities by passing an electric current between said substrate and said counterelectrode, while maintaining said substrate anodic with respect to said counter-electrode, whereby a Nernst diffusion layer is established at said substrate surface;
- and
- maintaining said diffusion layer at a thickness to produce a macroprofile regime for at least the largest of said macroasperities for a period of time until said macroasperities have been reduced to a height less than about 100 micrometers, thereby being converted into microasperities;
- and
- in a second step,
- reducing said microasperities by
- continuing said passing an electric current while maintaining said diffusion layer at a thickness to produce a microprofile regime.
Dependencies are inferred from the claim text.