JP2002541427A - Composite armor and manufacturing method thereof - Google Patents

Abstract

SUMMARY A composite component in an armored vehicle or armored garment includes a reactive sintered ceramic matrix having ceramic fibers embedded therein. Preferably, the reaction sintered ceramic matrix comprises nitride bonded silicon carbide and the ceramic fibers comprise silicon carbide. The matrix may further include a nitride-bound boron carbide. In the method of the present invention, a layer of non-woven monofilament silicon carbide is formed, a slip comprising silicon carbide and silicon powder is provided around the layer, and a matrix is formed around the layer. The silicon / silicon carbide matrix is then reaction sintered to form the composite component of the present invention.

Description

DETAILED DESCRIPTION OF THE INVENTION

Related Application This application is related to US Provisional Application No. 60 / 127,2, filed March 31, 1999.
No. 45, which claims priority and is incorporated by reference in its entirety, and is hereby incorporated by reference.

BACKGROUND OF THE INVENTION Conventional armor is generally known as KEVLAR para-aramid cloth (W
E. Ilmington, Delaware, USA. I. DuPont de
Nemours), SPECTRA polyethylene fabric (Morr)
available from Honeywell, iston, New Jersey, USA), fiberglass cloth, rubber, or aluminum honeycomb (honeyco).
mb) comprising a monolithic component such as aluminum oxide (Al ₂ O ₃ ), silicon carbide (SiC) or boron carbide (B ₄ C) attached to a backing material. This type of armor is routinely used to protect vehicles such as tanks, aircraft, space stations, etc., and to protect solids including military personnel and police officers, for example, when incorporated in bulletproof vests.

Recently, efforts have been made to manufacture protective gear from composite materials, rather than monolithic materials. The main advantage of using composite materials is that they can provide higher fracture toughness compared to monolithic materials. However, such efforts have focused on hot pressed composites. Although hot pressing is effective for producing dense composites, this method is expensive and is limited to producing simple shapes. Furthermore, hot pressing generally requires the use of sintering aids, and the high temperatures required for hot pressing (generally above 1600 ° C.) tend to disrupt the continuous fibers placed in the matrix.

SUMMARY OF THE INVENTION [0004] The composite element of the present invention is a vehicle substructure.
Armored ga on top or to protect the wearer from projectiles
rment) is a component of the armor shell. The composite component of the present invention comprises a reaction sintered ceramic matrix with embedded ceramic fibers.

In the method of the present invention, a layer of non-woven monofilament silicon carbide fibers is formed,
A slip containing silicon carbide (SiC) powder and silicon powder is cast around the layer to form a matrix around the layer. Next, the matrix is reaction sintered to form the composite component of the present invention. Alternatively, the silicon carbide powder can be at least partially replaced by boron carbide (B ₄ C). The composite component is then applied to the vehicle undercarriage or clothing worn by a person to protect the vehicle / wearer from ballistics (eg, bullets, explosives and / or missiles depending on the application). .

[0006] The composite components and methods of the present invention have many advantages in terms of cost, performance, and ease of manufacture. For example, the reaction sintered composite component of the present invention can be manufactured at a lower cost than a hot pressed composite, and the reaction sintering method allows for the incorporation of continuous fiber reinforcement. Furthermore, the composite components of the present invention can withstand many ballistic impacts despite their high porosity compared to common hot pressed composites.
Furthermore, the reaction-sintered composite component of the present invention can be easily formed into various complicated shapes, and has much better design freedom as compared to a hot-pressed composite,
It can be better adapted to the optimal shape required for the vehicle and body armor. Further, the reactive sintering method of the present invention binds the matrix particles at much lower temperatures and pressures than required for hot pressing or sintering.

[0007] The foregoing and other objects, features and advantages of the invention will be apparent from the following detailed description of preferred embodiments of the invention, as illustrated in the drawings. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to armored vehicles and armored garments comprising at least one composite component including ceramic fibers embedded in a reactive sintered ceramic matrix. The term "armor" as used herein refers to a protective covering designed to prevent ballistic penetration. In addition, "fiber" and "
The term "fibers" is used interchangeably herein,
Means one long filament or multiple filaments. The terms "armored clothing" and "body armor" are also used interchangeably herein.

In a preferred embodiment of the composite armor of the present invention, the present invention is applied to a fabric such as KEVLAR or fiberglass cloth for producing semi-rigid body armor, or to a substrate such as a rubber slab or aluminum honeycomb. The reaction sintering composite components are combined or fixed to produce a composite armor. In the case of the body armor 10 shown in FIG. 1, the composite component 12 is a component of the garment designed to protect the wearer of the vest from ammunition from bullets or other ballistics. In the latter case, a vehicle component 24 such as an aircraft, spacecraft, or land vehicle (eg, the tank 20 shown in FIG. 2)
A composite armor 22 is attached to protect the vehicle from bullets, missiles and explosives.

[0010] The armor or "body armor" of the present invention can be of a rigid or semi-rigid design. In rigid body armor, the composite component is generally a large molded panel designed to cover a given part of the human body. Semi-rigid armor clothing is generally
Includes a plurality of composite components in the form of relatively small movable coupling plates reinforced with a woven ballistic material such as EVLAR cloth.

The use of armor clothing to protect living organs is of particular importance. Accordingly, a preferred embodiment of the present invention is a vest-like garment that protects the torso. The armor suit of the present invention provides protection not only for ballistics but also for clubs and other hard objects that can cause injury in combat or accidents (eg, vehicle collisions). Due to the high resistance of the composite component of the present invention to deformation, dullness can pose a significant danger to non-rigid armor wearers due to armor deformation when subjected to strong impacts by projectiles such as bullets. Trauma (
Against blunt trauma), the armor of the present invention provides protection.

[0012] Based on the body armor classification system established in Standard 0101.03 by the National Institute of Justice (NIJ), the type I to type IV armor "type" is a threat that a given armor product may protect against (Threat) level. Fabric-based armor systems, such as armor using KEVLAR cloth, are commonly used against threats from small caliber trajectories, while the "hard" armor of the present invention is highly resistant to high levels of threat. Preferred for use as Type III, III-A or IV body armor.
Type III-A armor consists of. Designed to protect against 44 magnum and 9mm submachine gun ammunition. Type III armor is designed to protect against high power rifle ammunition. Finally, Type IV armor is designed to protect against "armor-piercing" ammunition.

In a preferred embodiment, the ceramic fibers are formed from silicon carbide, the fibers comprising about 4 to about 10% by volume of the composite comprising SiC fibers and a bonded SiC matrix or a bonded B ₄ C matrix. Complex component is vehicle armor or type I
When used as a V-body armor system, a fiber content of about 6 to about 10% by volume is preferred. For Type III or Type III-A body armor (for protection against unarmored penetrating ammunition), composite materials that can withstand many impacts can be formed with a fiber content of about 4 to about 6% by volume. .

[0014] Preferably, the fiber is Textron Systems Corps. (Wi
lmington, Massachusetts, U.S.A. S. A. SCS-6 (TM) fiber, available from S.I. SCS-6 ™ fiber is made from carbon monofilament and has a circular cross section of 140 microns (μm) in diameter. Alternatively or additionally, a 79 μm fiber (Textron System)
ems Corp. (Commercially available as SCS-9A ™). In SCS-6 ™ fibers, carbon monofilaments are about 35 μm in diameter. The fibers are coated with a carbon rich silicon carbide buffer of about 17 μm thickness by chemical vapor deposition of silane blend, hydrogen, argon and propane feeds. The buffer layer is then coated with a stoichiometric silicon carbide bulk layer of about 32 μm thickness applied by chemical vapor deposition. Finally, an approximately 3 μm thick carbon-rich silicon carbide deposition layer is applied by chemical vapor deposition as a surface coating on the silicon carbide bulk layer.

[0015] The reaction sintered ceramic matrix in which the fibers are embedded preferably comprises nitride-bonded silicon carbide and / or nitride-bonded boron carbide. In a "reaction sintering" process, which is derived from a method for producing a monolithic ceramic, at least one component of the matrix is chemically reacted with a liquid or gas. In this example, a blend of silicon carbide powder and silicon metal is consolidated by nitridation of the silicon metal to obtain a Si ₃ N ₄ bonded SiC matrix with a continuous SiC filament reinforcement. The nitride bonding process generally results in a matrix having a higher porosity (typically about 10% to about 20%) than the hot pressed or sintered material. SiC
Wherein the matrix based on comprises about 20% by weight of silicon nitride,
The resulting porosity is between about 14% and about 18%. Further, the matrix can also include cubic boron nitride. The matrix concentration of cubic boron nitride is preferably about 20%, which provides the greatest barrier to ballistic penetration in regions selected depending on the nature of the ballistics designed to protect against it. .
In one embodiment, this region extends 2 mm from the surface exposed to the impact.
In another aspect, the region is in the inner portion of the armor or extends from an inner surface remote from impact, thereby subjecting the trajectory to initial shearing before reaching the cubic boron nitride hardened region. Can be.

In the method of the present invention, a layer of non-woven monofilament silicon carbide fibers is formed,
A slip comprising silicon carbide powder and silicon powder is provided around the layer (ca
st) Form a matrix. Next, the matrix is reaction sintered to form a composite component. Next, the composite component is attached to the vehicle structure to produce an armored vehicle,
Alternatively, it is attached to clothing to form armored clothing.

In one embodiment, a composite material is prepared starting with a slip of the following formulation in which the approximate weight percent of each component is indicated in brackets: silicon carbide powder or silicon carbide powder and boron carbide Powder mixture (70% -75%), silicon powder (8% -12
%), Red iron oxide and sodium silicate (1-3%) and distilled water (10-20%). Specific formulations of preferred slips of SiC and silicon ground by particle size splitting are as follows: 0.1-1.0 μm β-SiC particles 13.96% 1-2 μm β-SiC particles 7.49% 2 7.-3 μm β-SiC particles 5.20% 3-4 μm β-SiC particles 2.54% 4-10 μm β-SiC particles 2.54% 80-120 μm β-SiC particles 42.30% 5-10 μm silicon particles 8. 46% 10 to 14 μm Silicon particles 2.12% Red stem 1.44% Sodium silicate 0.08% Water (distilled water) 13.87%

The slip is continuously rotated in the closed container of the electric drum roller to stir and mix. In a closed container, a dense rubber ball is used to assist the mixing process.

A gypsum mold is used to form the final shape of the composite component, in this case in the form of a plate. The height of the perimeter of the mold determines the thickness of the plate. First, a thin layer of the slip is placed in the mold, and then a separating layer of SCS-6 fiber is placed over the slip. SCS
The -6 fibers can be arranged in alternating 0 ° and 90 ° orientations, equally spaced or closer to one side of the plate. Each layer of fiber is between alternating applications of the slip, and the slip is applied above and below the first and last layers of fiber. When the fiber addition is finished, slip the final application slip over the mold.

The green body is removed from the gypsum mold and dried in an oven set at 100 ° C. to 120 ° C. Place the dried plate in the oven and place under vacuum. Raise the furnace temperature at a rate of 5 ° C./min. At 500 ° C., isolate the vacuum system,
Fill the furnace with nitrogen. Maintaining the nitrogen pressure at 800 Torr throughout the rest of the nitridation cycle converts the pure silicon metal to silicon nitride, thereby "nitriding" the silicon carbide matrix. At 950 ° C., ramp rate is reduced to 2.5 ° C./min until 1150 ° C. is reached, and the temperature is maintained at 1150 ° C. for 6 hours. Next, the temperature is increased to 1250 ° C. at a rate of 0.42 ° C./min. The temperature is then maintained at 1250 ° C. for 6 hours, and then
Raise to 50 ° C. The temperature is then maintained at 1350 ° C. for 8 hours, then 0.37
Increase to 1395 ° C. at a rate of 5 ° C./min. Finally, the temperature is maintained at 1395 ° C. for 6 hours to complete the cycle and then cooled to room temperature. The ceramic plate is removed from the furnace and, in one embodiment, machined with diamond saw blades to the final required plate dimensions.

The ceramic plate manufactured by the above method contains α-Si ₃ N ₄ bonded silicon carbide having a continuous silicon carbide fiber reinforcement. Density range 2.65 to 2.7
0 g / cc.

In an alternative embodiment, the particulate material can be replaced to change the characteristic hardness and density of the ceramic plate. In one example, the slip formulation is the same as above, except that instead of 80-120 μm SiC particles, 50 μm
m boron carbide particles are used. This replacement reduces the density of the plate to 2.35 g.
/ Cm ³ , despite substantially reducing the ballistic performance of the final nitride-bound composite plate.

If very high hardness is required for the plate, preferably about 30-65 μm
Particles of cubic boron nitride having a particle size of are used in place of some of the silicon carbide particles or boron carbide particles. The cubic boron nitride makes up about 20% of the slip and it is preferred to add this slip to the mold at the stage where the layer is placed where the hardest areas are needed, generally at the surface. The hardness obtained in this region can be 40% to 50% higher than the rest of the plate.
Possible uses of such hardened plates include Type IV body armor systems and vehicle armor systems where higher ballistic performance is required.

Although porosity is generally thought to reduce the fracture toughness of the material, the relatively porous composite components of the present invention exhibit advantageous performance as compared to the performance of denser hot pressed materials. it is conceivable that. It is believed that the porosity in the composite component of the present invention acts as a crack generator that delays the dispersion of energy when the material is exposed to high impact, while the fibers of the composite material crack while binding the component. Dulls and absorbs energy. In addition, it is believed that the carbon-rich surface coating of the fibers promotes the crack inhibiting properties of the present invention. Thus, the composite component of the present invention has the ability to withstand many impacts from high-speed projectiles without grinding.

EXPERIMENTAL The invention is illustrated by the following examples, which are not intended to limit the scope of the invention.

Example 1 A composite component of the present invention was formed by the method described above. In particular, the slip comprised silicon carbide powder (74%), silicon powder (11%), petiole (1.5%), sodium silicate (<1%) and distilled water (14%). . The fiber reinforcement formed 10% by volume of the matrix / fiber composite and was in the form of a set of continuous fiber layers arranged orthogonal to one another. The composite component has a density of 2.7 g / cm ³ and about 15
% Porosity. American Society For Tes
ting and Materials (ASTM) standard C11
In a four-point bending test performed according to 61-94, the ultimate stress was 137.5 MPa.
And the bending ratio was 107.9 GP. ASTM standard C1
34-97, dynamic mechanical resonance (D)
When the MR) test was used, a higher bending modulus (138 GPa) was obtained.

Example 2 In this example, the nitride-bonded silicon carbide composite material of the present invention was produced in the same manner as in the above example, except that the fiber orientation was limited to a single direction. A four point bending test showed a strength of 172 MPa and a modulus of 127 GPa in the fiber direction when used in this example. Again, higher values of flexural modulus (154 GPa) were obtained when using the dynamic mechanical resonance (DMR) test.

Example 3 For comparison, an unreinforced nitride-bonded silicon carbide matrix was formed according to the previous example without using fibers. The matrix was found to have an ultimate stress of 58 MPa and a modulus of 117 GPa as measured by a four-point bending test. Again, the measurements obtained from the Dynamic Mechanical Resonance (DMR) test are:
A higher value (124 GPa) of the bending rate was shown.

Equivalents While the present invention has been particularly shown and described with respect to preferred embodiments thereof, various modifications may be made in form and detail without departing from the spirit and scope of the invention as defined by the appended claims. Those skilled in the art will appreciate that they can be added.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of an armor suit of the present invention.

FIG. 2 is a diagram showing an embodiment of an armored vehicle according to the present invention.

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SL, SZ, TZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CR, CU, CZ, DE, DK, DM, DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR , HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA , ZW (72) Inventors Darden, William, S .; United States Massachusetts 01740 Bolton, Belleville Road 190 (72) Inventor Treasure, Monte, A. United States New Hampshire 03076 Pelham, Overlook Drive 3 (72) Inventor Singler, Robert, E. United States Massachusetts 02478 Belmont, Selwyn Road 53 (72) Inventor Divona, Garry, S.E. United States New Hampshire 03031 Amherst, Douglas Drive 13 F-term (reference) 2C014 KK01 4G001 BA22 BA23 BA62 BA86 BB22 BB23 BB86 BC44 BD11 BD14

Claims (29)

[Claims] 1. An armored vehicle having an armor shell comprising at least one composite component comprising: a) a reaction sintered ceramic matrix; and b) ceramic fibers embedded in the ceramic matrix. 2. The armored vehicle according to claim 1, wherein the reaction sintered ceramic matrix comprises at least one member selected from the group consisting of nitride-bonded silicon carbide and nitride-bonded boron carbide. 3. The armored vehicle of claim 1, wherein the reaction sintered ceramic matrix comprises nitride-bonded silicon carbide. 4. The armored vehicle according to claim 3, wherein the ceramic fibers comprise silicon carbide. 5. The armored vehicle according to claim 4, wherein the ceramic fibers are in the form of a non-woven monofilament. 6. The reaction sintered ceramic matrix is porous.
The armored vehicle described. 7. The armored vehicle of claim 6, wherein the porosity of the composite component ranges from about 10% to about 20%. 8. The armored vehicle of claim 5, wherein the amount of nonwoven monofilament ceramic fibers in the composite component ranges from about 6% to about 10% by volume. 9. A nonwoven monofilament silicon carbide fiber having a thickness of about 79 μm to about 1 μm.
An armored vehicle according to claim 5, having an average diameter in the range of 40 µm. 10. The armored vehicle according to claim 9, wherein the non-woven monofilament silicon carbide fibers have an average diameter of about 140 μm. 11. The armored vehicle according to claim 5, wherein the non-woven monofilament silicon carbide fibers are arranged in a matrix in a layered manner. 12. The armored vehicle according to claim 5, further comprising cubic boron nitride in the reaction sintered ceramic matrix. 13. An armored vehicle according to claim 12, wherein the cubic boron nitride is selectively enriched in the region of the reaction sintered ceramic matrix. 14. At least one of: a) a reactive sintered ceramic matrix; and b) ceramic fibers embedded in the ceramic matrix, wherein the at least one is adapted to protect a wearer of armored garment from ballistic penetration. Armored clothing containing two composite components. 15. The armored garment of claim 14, wherein the reaction sintered ceramic matrix comprises at least one member selected from the group consisting of nitride-bonded silicon carbide and nitride-bonded boron carbide. 16. The armor garment of claim 14, wherein the reaction sintered ceramic matrix comprises nitride bonded silicon carbide. 17. The armor suit according to claim 16, wherein the ceramic fibers comprise silicon carbide. 18. The armored garment of claim 17, wherein the ceramic fibers are in the form of a non-woven monofilament. 19. The armor suit of claim 18, wherein the nitride-bonded silicon carbide matrix is porous. 20. The armored garment of claim 19, wherein the porosity of the composite component ranges from about 10% to about 20%. 21. The armored garment of claim 19, wherein the amount of nonwoven monofilament ceramic fibers in the composite component ranges from about 4% to about 6% by volume. 22. The armored garment of claim 19, wherein the non-woven monofilament ceramic fibers are layered in parallel in a matrix. 23. The armor suit of claim 15, wherein the reaction sintered ceramic comprises cubic boron nitride. 24. The armor suit of claim 23, wherein the cubic boron nitride is selectively enriched in regions of the reaction sintered ceramic matrix. 25. The armored garment of claim 14, further comprising a woven ballistic fiber that reinforces the composite component. 26. a) forming a layer of non-woven monofilament silicon carbide fibers; b) subjecting a slip comprising silicon carbide powder and silicon powder to a periphery of the layer of non-woven monofilament silicon carbide fibers to form a powder. C) reacting the powder / fiber composition to form a reactive sintered composite component; and d) reacting to form a defense around the vehicle undercarriage. Attaching the sintered composite component to a vehicle undercarriage, comprising: forming a composite component and incorporating it into an armored vehicle. 27. The slip of claim 2, further comprising a boron carbide powder.
6. The method according to 6. 28. a) forming a layer of non-woven monofilament silicon carbide fibers; b) subjecting a slip comprising silicon carbide powder and silicon powder to a periphery of the layer of non-woven monofilament silicon carbide fibers to form a powder. C) reactive sintering the powder / fiber composition to form a reactive sintered composite component; and d) worn by the individual to protect the individual from projectiles. Attaching the reactive sintered composite component to the garment. 29. The slip of claim 2, further comprising a boron carbide powder.
8. The method according to 8.