US4722763A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for making irregular shaped single crystal particles for use in anodes for electrochemical cells
Assignee: Duracell Inc USA
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Filing: 1986-12-23
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Granted: 1988-02-02
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Expires: 2006-12-23
Abstract
Abstract A method of making single crystals of metal or other crystallizing materials whereby powders of irregular shaped single crystal particles (as small as 325 mesh or about 50 microns) may be readily and economically made. Said method comprises the steps of: (a) forming thin individual coatings on each of said particles such as oxides of metals on metal particles; (b) adding a combustible material to the coated particles and subjecting the combustible material to combustion; (c) melting the particle material within said coatings which function as individual particle crucibles; (d) cooling the melted particles within the coatings to form individual single crystals each within its own coating; and (e) removing the coating such as by solvation with a solvent or by chemical reaction. The single crystal particles conform to the original shape of the particles which may be irregular. Such irregular shaped single crystals, such as of zinc, when used in electrochemical cell anodes enables the utilization of reduced amounts of mercury for amalgamation thereof without significant increase in cell gassing.
Inventors
- 👤 David Pa
- 👤 Ronald A. Putt
- 👤 Douglas Black
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:05
CPC Classifications
H; H01; H01M; H01M4/00; H01M4/02; H01M4/36; H01M4/38; C; C30; C30B; C30B11/00; C30B11/002; C30B29/00; C30B29/02; C30B29/60; Y; Y02; Y02E; Y02E60/00; Y02E60/10
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
197 words
In a method for making single crystal metal particles consisting of the steps of: (a) forming individual substantially continuous coatings on the external surfaces of each of the individual particles of a particulate metal material which is capable of being crystallized, said coatings being of a material having higher melting and decomposition temperatures than the melting and decomposition temperatures of said particulate metal material and wherein said coatings are each of a thickness and composition with sufficient mechanical strength to act as self supporting shape retaining crucibles for said metal particles when such metal particles are melted; (b) raising the temperature of said coated particulate metal material to above the melting point thereof but below the lower of the melting point or the decomposition temperature of said coating material whereby substantially all of the particulate metal material is melted within said coating; and (c) slowly cooling said particulate metal material whereby substantially all of said particles become individual single metal crystals; the improvement which comprises adding a combustible material to the container containing said coated particulate metal material prior to commencing step (b), said material being capable of totally combusting at the temperatures employed in step (b).
Claim 2
Dependent Claim
197 words
In a method for making single crystal metal particles consisting of the steps of: (a) forming individual substantially continuous coatings on the external surfaces of each of the individual particles of a particulate metal material which is capable of being crystallized, said coatings being of a material having higher melting and decomposition temperatures than the melting and decomposition temperatures of said particulate metal material and wherein said coatings are each of a thickness and composition with sufficient mechanical strength to act as self supporting shape retaining crucibles for said metal particles when such metal particles are melted; (b) raising the temperature of said coated particulate metal material to above the melting point thereof but below the lower of the melting point or the decomposition temperature of said coating material whereby substantially all of the particulate metal material is melted within said coating; and (c) slowly cooling said particulate metal material whereby substantially all of said particles become individual single metal crystals; the improvement which comprises adding a combustible material to the container containing said coated particulate metal material prior to commencing step (b), said material being capable of totally combusting at the temperatures employed in step (b).
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein said coatings are each removed without substantially disrupting said single crystals.
Claim 4
Dependent Claim
14 words
The method of claim 1 wherein said coatings are each about 1 micron thick.
Claim 5
Dependent Claim
15 words
The method of claim 1 where in single crystal particles are of an irregular shape.
Claim 6
Dependent Claim
20 words
The method of claim 1 wherein the particular metal material has a particle size between about 50 and 500 microns.
Claim 7
Dependent Claim
16 words
The method of claim 1 wherein said particulate metal material is melted in a non-reactive environment.
Claim 8
Dependent Claim
27 words
The method of claim 1 wherein said particulate metal material is comprised of particles of irregular shape and said single crystals are of substantially corresponding irregular shape.
Claim 9
Dependent Claim
16 words
The method of claim 1 wherein said coating material is an oxide of said metal material.
Claim 10
Dependent Claim
37 words
The method of claim 8 wherein said coating material is formed on said metal particles by heating said metal particles in the presence of an oxidant at an elevated temperature below the melting point of said metal.
Claim 11
Dependent Claim
21 words
The method of claim 9 wherein said metal is zinc and said elevated temperature is between 370° C. to 400° C.
Claim 12
Dependent Claim
26 words
The method of claim 8 wherein said metals are selected from the group consisting of aluminum, cadmium, lead, lithium, magnesium, potassium, rubidium, sodium, tin and zinc.
Claim 13
Dependent Claim
17 words
The method of claim 2 wherein the removal of said oxide coating is effected by solvation thereof.
References Cited (Backward Citations)
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US4033792A
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US4487651A
Cited
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Cited
US4585716A
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US4637855A
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US4632890A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-02-01 | 1991-08-03 | 1992-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-01 | 1995-08-03 | 1996-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-01 | 1999-08-03 | 2000-02-02 | $7700.00 | Window Closed / Lapsed |