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US 5,215,631 AGranted
Electrolytic preparation of tin, other metals, alloys and compounds
AssigneeCel Systems Corporation
InventorRichard M. Westfall
Life of this patent
Estimating the term…
Abstract
Electrolytic processes for the growth of crystalline tin or other elemental crystals, with or without the use of a substrate. Exemplified cubic forms of alpha-tin and tetragonal forms of beta-tin are grown using a shaped anode and a pointed cathode to provide electrical geometric fields within an electrodeposition system to enhance the growth of the desired crystalline tin.
Claims17
A process for electrolytically producing elemental free-standing single crystals and free-standing dendritic crystalline materials chosen from the group consisting of:
- beryllium, magnesium, calcium, strontium, barium, scandium, yttrium, lanthanum, actinium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium, boron, aluminum, indium, thallium, carbon, tin, lead, arsenic, antimony, bismuth, selenium and tellurium, by performing the steps of:
- forming a solvent molten salt bath such as a single alkali halide salt or a eutectic metal halide mixture capable of supporting high solubilities for cations of the to-be-deposited material with molten salt bath melting point less than the melting point of the material to be produced as a single crystal;
- purifying the solvent eutectic metal halide molten salt bath with appropriate oxygen removal and purification treatments such as:
- electropurification, addition of free metal, and bubbling of gases such as HF, HCl, HBr, HI, and H2 under vacuum;
- dissolving a metal halide salt composed of the to-be-deposited metal and appropriate halide ion(s) as the solute in the molten salt bath in order to provide sufficient bulk-replenishing concentration (activity) of the cations of the material to be deposited as a crystal upon passage of electrical current;
- purifying the electrolytic bath containing the to-be-deposited cations through electropurification where current is passed from a high purity sacrificial anode of the material to be deposited to a cathode operated at potentials slightly more negative than the cathodic surface potential used in production of the to-be-produced material;
- immersing a cathode and an anode into said bath, said cathode being shaped in a manner to be capable of providing for nucleation of the cations on the tip of the pointed cathode, and said anode shaped to substantially replicate the crystallographic morphology desired;
- application of an electrical voltage between the anode and the cathode, with applied cathodic potentials more negative than the reduction potential of the cations of the to-be-produced material, yet above the critical overpotential (cathode driving negative) for the composition of the bath;
- and
- reduction of the cations of the material to be deposited at the cathode by the passage of said electrical current to thereby form a crystalline metal deposit at the cathode.
7 more elements
A process for electrolytically producing elemental free-standing single crystals and free-standing dendritic crystalline materials chosen from the group consisting of silicon and germanium by performing the steps of:
- forming a solvent molten salt bath, a eutectic metal halide mixture capable of supporting high solubilities for cations of the to-be-deposited material and a molten salt bath melting point less than the melting point of the material to be produced as a single crystal;
- purifying the solvent eutectic metal halide molten salt bath with appropriate electropurification, addition of free metal, and bubbling of gases such as HF, HCl, HBr, HI, and H2 under vacuum;
- dissolving a metal halide salt composed of the to-be-deposited metal and appropriate halide ion(s) as the solute in the molten salt bath in order to provide sufficient bulk-replenishing concentration (activity) of the cations of the material to be deposited as a crystal upon passage of eleotrical current;
- purifying the electrolytic bath containing the to-be-deposited cations through electropurification where current is passed from a high purity sacrificial anode of the material to-be-deposited to a cathode operated at potentials slightly more negative than the cathodic surface potential used in production of the to-beproduced material;
- immersing a cathode and an anode into said bath, said cathode being shaped in a manner to be capable of providing for nucleation of the cations on the tip of the pointed cathode and said anode shaped to substantially replicate the crystallographic morphology desired;
- application of an electrical voltage between the anode and the cathode, with applied cathodic potentials more negative than the reduction potential of the cations of the to-be-produced material, yet above the critical overpotential (cathode driving negative) for the composition of the bath;
- and
- reduction of the cations of the material to be deposited at the cathode by the passage of said electrical current to thereby form a crystalline metal deposit at the cathode.
5 more elements
Dependencies are inferred from the claim text.