US2009178741A1PendingUtilityA1
Method Of Making Reactive Composite Materials and Resulting Products
Assignee: REACTIVE NANOTECHNOLOGIES INCPriority: Jan 11, 2008Filed: Jan 12, 2009Published: Jul 16, 2009
Est. expiryJan 11, 2028(~1.5 yrs left)· nominal 20-yr term from priority
C06B 45/14
46
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Claims
Abstract
Novel reactive composite materials and associated methods for making the same which are pertinent to numerous new or improved applications. The method for making the reactive composite materials utilizes mechanical deformation to manufacture such materials with controlled, predictable characteristics. In the first deformation step, an assembly of reactive layers and/or particles is plastically deformed to reduce its cross sectional area by one-half or more. Portions of the deformed sheets are stacked or bent into a new assembly, and the new assembly is then deformed. The steps of assembly and deformation are repeated a sufficient number of times that the resulting materials are only locally layered but have relatively uniform reaction velocity and heat generating characteristics predictable by stochastic models derived herein.
Claims
exact text as granted — not AI-modified1 . An ignitable locally layered reactive composite material structure comprising alternating non-uniform layers of two or more materials that react exothermically along a self-propagating front with a predictable front velocity V.
2 . The locally layered reactive composite material of claim 1 wherein the alternating non-uniform layers can be characterized by a bilayer probability density function whose numerical or weighted mean, δ, is within the range 50 nanometers to 50 micrometers.
3 . The locally layered reactive composite material of claim 2 wherein the predictable front velocity V depends on the properties of the materials and the bilayer probability density function.
4 . The locally layered reactive composite material of claim 3 wherein the front velocity V can be mathematically expressed as:
V
=
K
δ
(
Δ
H
rx
Δ
H
th
)
p
(
1
-
COV
)
q
where
K is a composition-dependent dimensional constant that ranges between 1×10 −6 m 2 /s and 2×10 −4 m 2 /s,
ΔH rx is the actual heat of reaction,
ΔH th is the theoretical heat of reaction that would be obtained assuming no intermixing at the interfaces between otherwise chemically-distinct layers,
p is a first exponent in the range 1-4, and
q is a second exponent in the range 1-2.
5 . The locally layered reactive composite material of claim 3 wherein the front velocity V can be mathematically expresses as:
V
=
K
δ
(
Δ
H
rx
Δ
H
th
)
p
where
K is a composition-dependent dimensional constant that ranges between 1×10 −6 m 2 /s and 2×10 −4 m 2 /s,
ΔH rx is the actual heat of reaction,
ΔH th is the theoretical heat of reaction that would be obtained assuming no intermixing at the interfaces between otherwise chemically-distinct layers, and
p is an exponent in the range 1-4.
6 . The locally layered reactive composite material structure of claim 1 wherein the materials that react exothermically react to form at least one of an aluminide, a silicide, or a boride.
7 . The locally layered reactive structure of claim 1 wherein one of the materials that reacts exothermically comprises aluminum and another of the materials that react comprises a material selected from the group consisting of Ni, Monel, Ti, Zr, Pt, and Pd.
8 . The locally layered reactive structure of claim 1 wherein one of the materials that react exothermically comprises a material selected from the group consisting of Al, Ti, Zr, Mg and Hf and another of the materials that react comprises an oxide of iron or and oxide of copper.
9 . The locally layered reactive structures of claim 1 wherein the structure is in the form of a sheet.
10 . The locally layered reactive structure of claim 1 wherein the structure is in the form of a wire or rod.
11 . A laminate structure comprising a plurality of locally layered reactive structures according to claim 1 , each of said locally layered reactive structures laminated together to form a laminated structure.
12 . A method of fabricating a locally-layered ignitable structure comprising the steps of:
(a) providing an assembly of alternating layers of materials that can exothermically react; (b) deforming the assembly to reduce its cross-section; (c) providing an assembly of a plurality of layers obtained as a result of the preceding deformation; and (d) repeating steps (b) and (c) for a sufficient number of times to produce a non-uniform, locally layered material having a predictable uniform reaction velocity.
13 . The method of claim 12 wherein the assembly of alternating layers comprises a stack of foil.
14 . The method of claim 12 wherein said step of deforming the assembly comprises at least one process selected from a set of processes including rolling, sheath rolling, warm rolling, swaging, extrusion, and hot pressing.
15 . The method of claim 14 wherein the rolling speed ranges between 10 −2 and 1 s −1 .
16 . The method of claim 12 wherein a first deformation step reduces a cross-section of said assembly by at least 50%.
17 . The method of claim 12 further including at least one edge-trimming step between each deformation step.
18 . The method of claim 12 wherein the initial assembly has width-to-thickness ratio of at least 200:1.
19 . The method of claim 12 wherein the materials in the assembly have a hardness ratio of no more than 1.5:1.
20 . The method of claim 12 wherein the assembly of alternating layers comprises a stack of foil and powder.
21 . A resulting assembly product made by the method of claim 12 .Join the waitlist — get patent alerts
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