Method for fabricating an ignitable heterogeneous stratified metal structure

• US 5,547,715 A
• Filed: 10/13/1995
• Issued: 08/20/1996
• Est. Priority Date: 07/15/1994
• Status: Expired due to Term

• Current Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Barbee, Troy W. Jr., Weihs, Timothy
• Primary Examiner(s): PIANALTO, BERNARD D
• Application Number:
  US08/542,976
• Time in Patent Office: 312 Days
• Field of Search: 427/561, 427/573, 427/576, 427/585, 427/404
• US Class Current: 427/561
• CPC Class Codes: C06B 45/14 a layer or zone containing an inorganic explosive or an inorganic explosive or an inorganic thermic component
• CPC Class Codes: C06C 9/00 Chemical contact igniters; Chemical lighters
• CPC Class Codes: C23C 14/14 Metallic material, boron or silicon
• CPC Class Codes: C23C 14/34 Sputtering
• CPC Class Codes: Y10S 428/93 Electric superconducting
• CPC Class Codes: Y10T 428/12493 Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
• CPC Class Codes: Y10T 428/125 Deflectable by temperature change [e.g., thermostat element]
• CPC Class Codes: Y10T 428/12812 Diverse refractory group metal-base components: alternative to or next to each other
• CPC Class Codes: Y10T 428/12986 Adjacent functionally defined components
• CPC Class Codes: Y10T 428/24967 Absolute thicknesses specified
• CPC Class Codes: Y10T 428/31536 Including interfacial reaction product of adjacent layers

Abstract

A multilayer structure has a selectable, (i) propagating reaction front velocity V, (ii) reaction initiation temperature attained by application of external energy and (iii) amount of energy delivered by a reaction of alternating unreacted layers of the multilayer structure. Because V is selectable and controllable, a variety of different applications for the multilayer structures are possible, including but not limited to their use as ignitors, in joining applications, in fabrication of new materials, as smart materials and in medical applications and devices. The multilayer structure has a period D, and an energy release rate constant K. Two or more alternating unreacted layers are made of different materials and separated by reacted zones. The period D is equal to a sum of the widths of each single alternating reaction layer of a particular material, and also includes a sum of reacted zone widths, t_i, in the period D. The multilayer structure has a selectable propagating reaction front velocity V, where

V=K(1/Dⁿ)×[1-(t_i /D)]and n is about 0.8 to 1.2.

Claims

1. A method for fabricating an ignitable heterogeneous stratified metal structure for supporting the propagation of an internal chemical reaction along an expanding wavefront from an ignition starting point that has alternating planar depositions of a first and a second exothermic-constituent material fused together as a whole with a mutual interface of said first exothermic-constituent material reacted with said second exothermic-constituent material, the method comprising the steps of:

maintaining a substrate at a temperature of less than 110°

C. in an argon atmosphere;

placing two target surfaces of a first exothermic-constituent material and a second exothermic-constituent material proximate to said substrate; and

applying a voltage to induce an argon plasma sheath, wherein argon atoms are accelerated to each target surface and provide kinetic energy to eject particles of said first and said second exothermic-constituent materials for deposit on said substrate in an alternating strata of said first exothermic-constituent material having a uniform thickness "t_a " in the range of 20-10,000 Å

, said second exothermic-constituent material having a uniform thickness "t_b " in the range of 20-10,000 Å

, an interface of reacted first and second exothermic-constituent materials having a thickness "t_i " in the range of 3-180 Å

, and each combination of said first exothermic-constituent material, said second exothermic-constituent material and twice said interface of reacted first and second exothermic-constituent materials having a recurring interval "D" in the range of 50-20,000 Å

.