Supercorroding galvanic cell alloys for generation of heat and gas

• US 4,264,362 A
• Filed: 08/13/1979
• Issued: 04/28/1981
• Est. Priority Date: 11/25/1977
• Status: Expired due to Term

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Jenkins, James F., Black, Stanley A., Sergev, Sergius S.
• Primary Examiner(s): Schafer, Richard E.
• Application Number:
  US06/066,200
• Time in Patent Office: 624 Days
• Field of Search: 428/550, 428/548, 252/188, 252/188.3, 423/657, 423/658, 75/249, 75/243, 75/246, 75/245
• US Class Current: 75/243
• CPC Class Codes: B22F 2009/041 by mechanical alloying, e.g. blending, milling
• CPC Class Codes: B22F 9/04 starting from solid material, e.g. by crushing, grinding or milling C22C1/1084 takes precedence; crushing, grinding or milling, in general, see the relevant subclasses, e.g. B02C
• CPC Class Codes: C22C 1/0408 Light metal alloys
• CPC Class Codes: F24V 30/00 Apparatus or devices using heat produced by exothermal chemical reactions other than combustion
• CPC Class Codes: H01M 8/065 by dissolution of metals or alloys; by dehydriding metallic substances
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y10T 428/12181 Composite powder [e.g., coated, etc.]

Abstract

Supercorroding magnesium alloys that operate like galvanic cells and reactapidly and predictably with seawater to produce heat and hydrogen gas. The alloys are formed by a mechanical process that bonds magnesium and noble metal powder particles together in a strong electrical and mechanical bond. The alloy powders can be compacted and sintered to form barstock, etc., suitable for making self-destructing corroding links.

Claims

1. Supercorroding galvanic cell alloys for generating heat and hydrogen gas upon activation in an electrolyte, comprising:

a. uniform mechanical alloy produced by the repeated flattening, fracturing and cold welding together of active anodic powered metal and passive cathodic powdered material constituents in an inert atmosphere to form minute mechanically alloyed composite galvanic cell particles of completely homogeneous mixture;

b. said anodic and cathodic powdered particles being substantially atomically clean and absent of oxides on their surfaces and being coupled into micro-cells having strong mechanical bonds and intimate atomic-level electrical contact;

said micro-cells having extremely short current path lengths between the alloyed constituents;

c. said anodic powdered metal and passive cathodic powdered material being mechanically alloyed to a point substantially less than saturation hardness for providing desired homogeneity and optimum reaction time in said electrolyte;

d. each of said uniform mechanically alloyed galvanic cell particles consisting of an active anodic metal matrix having numerous smaller particles of passive cathodic material trapped and dispersed throughout said active anodic metal matrix in a characteristic homogeneous layered structure;

e. said active anodic metal being powdered magnesium;

f. said passive cathodic powder material being selected from any of iron, copper, titanium, chromium, carbon, and nickel, including combinations thereof;

g. said mechanically alloyed galvanic cell particles being operable to corrode at a predictable and rapid rate in a desired electrolyte for producing heat and gas by proper selection of constituents and percentages thereof and the homogeneity of the alloy;

said mechanically alloyed galvanic cell particles having optimum electrical contact between active and passive material and no electrode gap to maintain resulting in minimal internal electrical resistance and improved reaction rates in suitable electrolyte;

wherein maximum corrosion rate and efficiency is provided with minimum electrolyte bath length, high exposed surface area ratio, strong welded bonds and less than 10^-4 ohms resistance for external currents to flow through between the corroding cathode and anode material pairs of the supercorroding galvanic cell alloyed particles.

2. Supercorroding galvanic cell alloys as in claim 1 wherein said active metal powder consists of from approximately 80 to 95 atomic percent powdered magnesium particles.

3. Supercorroding galvanic cell alloys as in claim 1 wherein said passive material powder consists of from approximately 0.5 to 20 atomic percent powdered iron particles.

4. Supercorroding galvanic cell alloys as in claim 1 wherein said passive material powder consists of from 1 to 10 atomic percent powdered copper particles.

5. Supercorroding galvanic cell alloys as in claim 1 wherein said passive material powder consists of up to approximately 5 atomic percent powdered titanium particles.

6. Supercorroding galvanic cell alloys as in claim 1 wherein said passive material powder consists of up to approximately 5 atomic percent powdered chromium particles.

7. Supercorroding galvanic cell alloys as in claim 1 wherein said passive material powder consists of up to approximately 5 atomic percent powdered carbon particles.

8. Supercorroding galvanic cell alloys as in claim 1 wherein said passive material powder consists of up to approximately 5 atomic percent powdered nickel particles.

9. Supercorroding galvanic cell alloys as in claim 1 wherein said passive material powder consists of up to approximately 20 atomic percent of a mixture of a plurality of said passive material powders.

10. Supercorroding galvanic cell alloys as in claim 1 wherein said mechanically alloyed galvanic cell particles are refined by continued milling thereof from approximately 5 to 30 minutes.

11. Supercorroding galvanic cell alloys as in claim 1 wherein preferred particle size of refined milled mechanically alloyed galvanic cell particles is between 80 and 100 mesh.

12. Supercorroding galvanic cell alloys as in claim 1 wherein the largest dimension of the passive material particles dispersed throughout said active metal matrix is approximately 30 microns.

13. Supercorroding galvanic cell alloys as in claim 1 wherein the generation of hydrogen produced upon activation of said powdered galvanic cell alloyed particles in an electrolyte is varied by controlling either the reaction temperature or the rate at which the galvanic cell alloyed particles are added to the electrolyte.

14. Supercorroding galvanic cell alloys as in claim 1 wherein said powdered mechanically alloyed galvanic cell particles are molded into desired shapes, compacted and sintered to form self-destructible articles for use in a suitable electrolyte.

15. A supercorroding alloy as in claim 14 molded, compacted and sintered into a rapidly corrodable link.

16. A supercorroding alloy as in claim 14 molded, compacted and sintered into a rapidly corrodable disc.

17. Supercorroding galvanic cell alloys as in claim 1 wherein the preferred atomic percent of iron is from 5 to 10.

18. Supercorroding galvanic cell alloys as in claim 1 wherein the optimum milling time for alloying the material powders into galvanic cell composite particles is approximately 30 minutes.

19. Supercorroding galvanic cell alloys as in claim 1 wherein inert ingredients are mixed with said mechanically alloyed particles to form an inert slurry of gel type consistency which facilitates pumping thereof.

20. Supercorroding galvanic cell aloys as in claim 19 wherein said slurry consists in proportion by weight of:

magnesium based mechanically alloyed powder 447.0, methoxy polyethylene glycol 394.0, N-oco beta amino butyric acid 3.0, collodial silica at least 19.7, diethylenetriamine 1.0.