WO2008063703A2

WO2008063703A2 - Armor composites and methods of making same

Info

Publication number: WO2008063703A2
Application number: PCT/US2007/068033
Authority: WO
Inventors: Anatoly Z. Rosenflanz; Donna W. Bange
Original assignee: 3M Innovative Properties Company
Priority date: 2006-05-17
Filing date: 2007-05-02
Publication date: 2008-05-29
Also published as: WO2008063703A3; JP2010505639A; EP2024177A2

Abstract

Armor composites and methods of making armor composites comprising a first layer comprising a glass-ceramic, a force dissipating material, and a bond that affixes at least a portion of the first layer to the second layer.

Description

ARMOR COMPOSITES AND METHODS OF MAKING SAME

Cross Reference To Related Application

This application claims the benefit of U.S. Provisional Patent Application No. 60/747,489, filed May 17, 2006, the disclosure of which is incorporated by reference herein in its entirety.

FIELD OF INVENTION

[0001] The present disclosure relates generally to armor composites. More particularly, the present disclosure relates to glass-ceramic composites, and methods of making glass-ceramic composites.

BACKGROUND

[0002] Various armor materials designed to resist the incursion of small arms projectiles and shrapnel are known. These armor materials can be made from glass- ceramics and plastic layers bonded together to form laminated composites. [0003] The majority of glass-ceramics utilize well-known glass-formers such as Siθ₂, B₂O3, P₂O5, Geθ₂, and Teθ₂ to aid in the formation of the glass precursor. WIPO Publication Number WO 2003/011776 and Rosenflanz et ah, Bulk glasses and ultrahard nanoceramics based on alumina and rare-earth oxides, Nature 430, 761-64 (2004), report novel bulk glass and glass-ceramic compositions that can be formed by consolidating glass bodies (e.g., a plurality of glass beads) that exhibit T_g and T_x. There is a continuing desire to develop new uses and applications for these novel glass-ceramic materials. SUMMARY

[0004] The present disclosure relates generally to armor composites. More particularly, the present disclosure relates to glass-ceramic composites, and methods of making glass-ceramic composites.

[0005] In one embodiment of the present disclosure is a composite material having a first layer comprising a glass-ceramic comprising a first metal oxide selected from the group consisting OfAl₂O₃, CaO, CoO, Cr₂O₃, CuO, Fe₂O₃, HfO₂, MgO, MnO, Nb₂O₅, NiO, REO, Sc₂O₃, Ta₂O₅, TiO₂, V₂O₅, Y₂O₃, ZnO, ZrO₂, and complex metal oxides thereof, and a second metal oxide selected from the group consisting Of Al₂O₃, Bi₂O₃, CaO, CoO, Cr₂O₃, CuO, Fe₂O₃, Ga₂O₃, HfO₂, MgO, MnO, Nb₂O₅, NiO, REO, Sc₂O₃, Ta₂O₅, TiO₂, V₂O₅, Y₂O₃, ZnO, ZrO₂, and complex metal oxides thereof, wherein the first metal oxide and the second metal oxide are different from one another, wherein the glass- ceramic comprises a hardness of at least 13 GPa, wherein the glass-ceramic has x, y, and z dimensions each perpendicular to each other, and each of the x and y dimensions is at least 10 millimeters, and wherein the glass-ceramic contains not more than 20 percent by weight SiO₂, not more than 20 percent by weight B₂O₃, and not more than 40 percent by weight P₂O₅, based on the total weight of the glass-ceramic. The composite material has a second layer comprising a force dissipating material, and a bond material that affixes at least a portion of the first layer to the second layer.

[0006] In another embodiment of the present disclosure is a method of making a composite transparent material by:

[0007] providing a plurality of glass bodies comprising a first metal oxide and a second metal oxide, wherein the first metal oxide and the second metal oxide are different from one another, the glass bodies having a T_g and T_x, wherein the difference between T_g and T_x is at least 5 degrees Celsius, and wherein the glass bodies contain not more than 20 percent by weight SiO₂, not more than 20 percent by weight B₂O₃, and not more than 40 percent by weight P₂O₅, based on the total weight of the glass bodies; [0008] heating the glass bodies above the T_g and coalescing at least a portion of the plurality of glass bodies to provide a bulk glass body; [0009] heat-treating the bulk glass body to form a glass-ceramic; [0010] providing a force dissipating material; [0011] applying a bond material to at least one of the glass-ceramic and the force dissipating material; and

[0012] laminating the glass-ceramic and the force dissipating material, is disclosed.

[0013] Using the methods of the present disclosure, armor composites can be made with high hardness (i.e., at least 13 GPa). The armor composites of the present disclosure can be used in a variety of applications, including, for example, as protection for military and armored vehicles (cars, jeeps, trucks, aircraft, tanks, trains, ships, amphibious vehicles, etc.), and in personal protection equipment such body armor.. The armor composites can also be used for stationary objects, including buildings, doors, bus stops, shelters, etc.

[0014] In this application:

[0015] "amorphous material" refers to material derived from a melt and/or a vapor phase that lacks any long range crystal structure as determined by X-ray diffraction and/or has an exothermic peak corresponding to the crystallization of the amorphous material as determined by DTA (differential thermal analysis);

[0016] "ceramic" includes glass, crystalline ceramic, and combinations thereof;

[0017] "complex metal oxide" refers to a metal oxide comprising two or more different metal elements and oxygen (e.g., CeAl₁₁OiS, Dy₃Al₅Oo, MgAl₂O₄, and

Y₃Al₅O₁₂);

[0018] "differential thermal analysis" or "DTA" refers to a procedure that involves measuring the difference in temperature between a sample and a thermally inert reference, such as Al₂O₃, as the temperature is raised. A graph of the temperature difference as a function of the temperature of the inert reference provides information on exothermic and endothermic reactions taking place in the sample. An exemplary instrument for performing this procedure is available from Netzsch Instruments, SeIb, Germany under the trade designation "NETZSCH STA 409 DTA/TGA". A suitable amount, e.g., 400 mg, of a sample can be placed in a suitable inert holder (e.g. a 100 ml Al₂O₃ sample holder) and heated in static air at a suitable rate, e.g. 10°C/minute, from an initial temperature (e.g. room temperature, or about 25°C) to a final temperature, such as 1200⁰C;

[0019] "glass" refers to amorphous material exhibiting a glass transition temperature;

[0020] "glass-ceramic" refers to ceramic comprising crystals formed by heat-treating glass; [0021] "glass-ceramic precursor" refers to the glass body that is subjected to heat- treatment to form a glass-ceramic;

[0022] "heat-treatment protocol" refers to all processing parameters (e.g., temperature, time, pressure, etc.) of the heat-treatment process;

[0023] "T_g" refers to the glass transition temperature as determined by DTA (differential thermal analysis);

[0024] "T_x" refers to the crystallization temperature as determined by DTA (differential thermal analysis); and

[0025] "rare earth oxides" or "REO" refers to cerium oxide (e.g., CeO₂), dysprosium oxide (e.g., Dy₂Os), erbium oxide (e.g., Er₂Os), europium oxide (e.g., Eu₂Os), gadolinium oxide (e.g., Gd₂Os), holmium oxide (e.g., Ho₂Os), lanthanum oxide (e.g., La₂Os), lutetium oxide (e.g., Lu₂Os), neodymium oxide (e.g., Nd₂Os), praseodymium oxide (e.g., Pr₆On), samarium oxide (e.g., Sm₂Os), terbium oxide (e.g., Tb₂Os), thorium oxide (e.g., Th₄O?), thulium oxide (e.g., Tm₂Os), and ytterbium oxide (e.g., Yb₂Os), and combinations thereof. [0026] Further, it is understood herein that unless it is stated that a metal oxide (e.g., Al₂Os, complex Al₂θ3-metal oxide, etc.) is crystalline, for example, in a glass-ceramic, it may be glass, crystalline, or portions glass and portions crystalline. For example, if a glass-ceramic comprises Al₂Os and ZrO₂, the Al₂Os and ZrO₂ may each be in a glassy state, crystalline state, or portions in a glassy state and portions in a crystalline state, or even as a reaction product with another metal oxide(s) (e.g., unless it is stated that, for example, Al₂Os is present as crystalline Al₂Os or a specific crystalline phase of Al₂Os (e.g., alpha Al₂Os), it may be present as crystalline Al₂Os and/or as part of one or more crystalline complex Al₂θ3-metal oxides).

[0027] The above summary of making armor composites according to the present disclosure is not intended to describe each disclosed embodiment of every implementation of making armor composites according to the present disclosure. The detailed description that follows more particularly exemplify illustrative embodiments. The recitation of numerical ranges by endpoints includes all numbers subsumed with that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 4, 4.80, and 5). DETAILED DESCRIPTION

[0028] The armor composite of the present disclosure comprises at least two layers bonded together by a bond material. The first layer comprises a glass-ceramic material with a high hardness that serves as a first line of defense when the composite is subjected to elements of an adverse environment (e.g., shock, scratching, abrasion, adverse weather conditions, etc.). In addition, the first layer may deform a projectile, thereby reducing the resulting impact on the armor composite.

[0029] WIPO Publication Number WO 2003/011776 and Rosenflanz et al, Bulk glasses and ultrahard nanoceramics based on alumina and rare-earth oxides, Nature 430, 761-64 (2004), report novel glass compositions that can be used to form glass and glass- ceramic useful in making the first layer of the armor composite according to the present disclosure, and are incorporated herein by reference. Glass and glass-ceramic precursors useful in making the first layer according to the present disclosure can also be obtained by other techniques, such as direct melt casting, melt atomization, containerless levitation, laser spin melting, and other methods known to those skilled in the art (see, e.g., Rapid Solidification of Ceramics, Brockway et al., Metals And Ceramics Information Center, A Department of Defense Information Analysis Center, Columbus, OH, January, 1984). [0030] The glass-ceramic of the first layer generally comprises a mixture of at least two metal oxides (or complex metal oxides). Metal oxides that may be used to form the glass-ceramic include, for example, AI₂O3; Tiθ₂; rare earth oxides (REO's) such as Ceθ₂, Dy₂O₃, Er₂O₃, Eu₂O₃, Gd₂O₃, Ho₂O₃, La₂O₃, Lu₂O₃, Nd₂O₃, Pr₆On, Sm₂O₃, Tb₂O₃, Th₄O₇, Tm₂O₃ and Yb₂O₃; ZrO2, HfO₂, Ta₂O₅, Nb₂O₅, Bi₂O₃, WO₃, V₂O₅, Ga₂O₃, and alkaline earth metal oxides such as CaO and BaO. Examples of useful glass-ceramics for making armor composites according to the present disclosure include those made from REO-TiO₂, REO-ZrO₂-TiO₂, REO-Al₂O₃, REO-Al₂O₃-ZrO₂, and REO-Al₂O₃-ZrO₂-SiO₂ glass- ceramic precursors. Useful glass-ceramic precursor formulations include those at or near a eutectic composition.

[0031] In addition to these compositions and compositions disclosed in WIPO Publication Numbers WO 2003/011781, WO 2003/011776, WO 2005/061401, U.S. Patent Application having Serial No. 11/273,513, filed November 14, 2005 (Attorney Docket No. 61351US002), and Rosenflanz et al, Bulk glasses and ultrahard nanoceramics based on alumina and rare-earth oxides, Nature 430, 761-64 (2004), which are incorporated herein by reference, other compositions, including eutectic compositions, will be apparent to those skilled in the art after reviewing the present disclosure.

[0032] In some embodiments, the first and second metal oxides are each selected from the group consisting Of Al₂O₃, Bi₂O₃, CaO, CoO, Cr₂O₃, CuO, Fe₂O₃, Ga₂O₃, HfO₂, MgO, MnO, Nb₂O₅, NiO, REO, Sc₂O₃, Ta₂O₅, TiO₂, V₂O₅, Y₂O₃, ZnO, ZrO₂, and complex metal oxides thereof.

[0033] In some embodiments, a first metal oxide is selected from the group consisting OfAl₂O₃, CaO, CoO, Cr₂O₃, CuO, Fe₂O₃, HfO₂, MgO, MnO, Nb₂O₅, NiO, REO, Sc₂O₃, Ta₂O₅, TiO₂, V₂O₅, Y₂O₃, ZnO, ZrO₂, and complex metal oxides thereof, and a second metal oxide is selected from the group consisting Of Al₂O₃, Bi₂O₃, CaO, CoO, Cr₂O₃, CuO, Fe₂O₃, Ga₂O₃, HfO₂, MgO, MnO, Nb₂O₅, NiO, REO, Sc₂O₃, Ta₂O₅, TiO₂, V₂O₅, Y₂O₃, ZnO, ZrO₂, and complex metal oxides thereof. In some embodiments, the first metal oxide is selected from the group consisting Of Al₂O₃, REO, TiO₂, Y₂O₃, ZrO₂, and complex metal oxides thereof.

[0034] In some instances, it may be preferred to incorporate limited amounts of oxides selected from the group consisting of: B₂O₃, GeO₂, P₂O₅, SiO₂, TeO₂, and combinations thereof. These metal oxides, when used, are typically added in the range of O to 20% (in some embodiments O to 15%, O to 10%, or even O to 5%) of the glass-ceramic depending, for example, upon the desired property.

[0035] In some embodiments, the glass-ceramic comprises at least 20 (in some embodiments, preferably at least 25, 30, 35, 40, 45, 50, 55, 60, 65, 70 or even at least 75) percent by weight Al₂O₃, based on the total weight of the glass-ceramic, and a metal oxide other than Al₂O₃ (e.g., Bi₂O₃, CaO, CoO, Cr₂O₃, CuO, Fe₂O₃, Ga₂O₃, HfO₂, MgO, MnO, Nb₂O₅, NiO, REO, Sc₂O₃, Ta₂O₅, TiO₂, V₂O₅, Y₂O₃, ZnO, ZrO₂, and complex metal oxides thereof).

[0036] In some embodiments, the glass-ceramic precursor is formed by coalescing a plurality of glass bodies (e.g., beads) comprising a first metal oxide and a second metal oxide, wherein the difference between T_g and T_x is at least 5 degrees Celsius, and wherein the glass bodies contain not more than 20 (in some embodiments 15, 10, 5, 3, 2, or even 1) percent by weight SiO₂, not more than 20 (in some embodiments 15, 10, 5, 3, 2, or even 1) percent by weight B₂O₃, and not more than 40 (in some embodiments 30, 20, 10, 5, 3, 2, or even 1) percent by weight P₂O₅, based on the total weight of the glass bodies. The coalescing step can be conducted by applying heat and/or pressure to the plurality of glass bodies. WIPO Publication Number WO 2003/011776, incorporated herein by reference, discloses methods for coalescing a plurality of glass bodies. The coalescing process can be used to shape the glass-ceramic precursor to a desired geometry. The glass-ceramic precursor can also be shaped using methods reported in copending application having U.S. Serial No. 60/797,847 (Attorney Docket No. 62097US002), entitled "Method of Reshaping a Glass Body", filed May 3, 2006, the disclosure of which is incorporated herein by reference.

[0037] In some embodiments, a combination of glass bodies that vary in composition and/or size can be coalesced to form the glass-ceramic precursor. The chosen compositions may be varied to create a glass-ceramic precursor with discontinuous properties. The discontinuous properties can create a glass-ceramic with varying appearance attributes. For example, the glass-ceramic can have shading effects, graded index of refraction, varying colors, and the like. Additions of transparent materials (i.e glass, crystalline bodies) based on Tiθ₂, Zrθ₂, Nb₂Os and Ta₂Os to a portion of the glass bodies based on AI₂O3, for example, may result in graded index of refraction and other light interference effects. Additions of optically active rare earth ions such as Nd₂Os , Er₂θ3_; Eu₂θ3, may affect the color. Likewise, the combination of different glass bodies may affect various thermo-mechanical, diffusional and physical properties, including, for example, coefficient of thermal expansion, thermal conductivity, electronic and ionic conductivity, hardness, fracture toughness, strength and density. [0038] The glass bodies that vary in composition may be uniformly mixed prior to coalescing or the glass bodies that vary in composition may be purposely segregated, for example, to form distinct layers or three-dimensional formations within the resulting article. For instance, depending upon the composition of the glass bodies and/or process conditions, after coalescing the resulting article may comprise distinct layers. These layers can be alternated to achieve a desired result. Conversely, after coalescing there may be migration of one layer into the other layer. The composition of the glass bodies and/or processing can be optimized to change any migration effect.

[0039] In one example, the glass body compositions can be chosen and oriented such that the outer portion of the glass-ceramic precursor may contain a harder composition and the inner portion may have higher strength. The compositions can also be chosen such that different portions of the glass-ceramic precursor exhibit different coefficients of thermal expansions, different thermal conductivity and diffusivity (e.g. gas diffusivity). Similarly the outer portion may contain a glass composition of a different color, shade or other optical effect from the inner portion.

[0040] The glass bodies to be coalesced can also be mixed with non-glass materials to create a composite glass-ceramic. Examples of such non-glass materials include: metals (e.g., aluminum, carbon steel, etc.) crystalline metal oxides (alumina, silica, zirconia, rare earth oxides, yttria, magnesia, calcia, etc.), metal carbides, metal nitrides, metal borides, diamond and the like. The non-glass material should not degrade upon the temperatures and pressures of coalescing and heat-treatment. These non-glass materials may serve to further increase the hardness and/or reduce the density of the glass-ceramic. [0041] In general, glasses that can be used to form glass-ceramic for making armor composites according to the present disclosure can be made by heating the appropriate metal oxide sources to form a melt, desirably a homogenous melt, and then cooling the melt to provide glass. Some embodiments of glass materials can be made, for example, by melting the metal oxide sources in any suitable furnace (e.g., an inductive heated furnace, a gas-fired furnace, or an electrical furnace), or, for example, in a flame or plasma. The resulting melt is cooled by discharging the melt into any of a number of types of cooling media such as high velocity air jets, liquids, graphite or metal plates (including chilled plates), metal rolls (including chilled metal rolls), metal balls (including chilled metal balls), and the like.

[0042] In one method, glasses that can be used to form the first layer of armor composites according to the present disclosure can be made utilizing flame fusion as disclosed, for example, in U.S. Pat. No. 6,254,981, incorporated by reference. Briefly, the metal oxide source materials are formed into particles sometimes referred to as "feed particles". Feed particles are typically formed by grinding, agglomerating (e.g., spray- drying), melting, or sintering the metal oxide sources. The size of the feed particles fed into the flame generally determines the size of the resulting amorphous particle material. The feed particles are fed directly into a burner such as a methane-air burner, an acetylene- oxygen burner, a hydrogen-oxygen burner, and like. The materials are subsequently quenched in, for example, water, cooling oil, air, or the like. [0043] Other techniques for forming melts, cooling/quenching melts, and/or otherwise forming glass include vapor phase quenching, plasma spraying, melt-extraction, gas or centrifugal atomization, thermal (including flame or laser or plasma-assisted) pyrolysis of suitable precursors, physical vapor synthesis (PVS) of metal precursors, and mechanochemical processing.

[0044] The cooling rate is believed to affect the properties of the quenched amorphous material. For instance, glass transition temperature, density and other properties of glass typically change with cooling rates. Rapid cooling may also be conducted under controlled atmospheres, such as a reducing, neutral, or oxidizing environment to maintain and/or influence the desired oxidation states, etc., during cooling. The atmosphere can also influence glass formation by influencing crystallization kinetics from undercooled liquid. [0045] Heat-treatment of the glass-ceramic precursor can be carried out in any of a variety of ways, including those known in the art for heat-treating glass to provide glass- ceramics. For example, heat-treatment can be conducted in batches, for example, using resistive, inductively or gas heated furnaces. The temperature may range anywhere from 900⁰C to 1600⁰C, typically between 1200⁰C to 1500⁰C. It is also within the scope of the present invention to perform some of the heat-treatment in batches (e.g., for the nucleation step) and another continuously (e.g., for the crystal growth step and to achieve the desired density). For the nucleation step, the temperature typically ranges between about 900⁰C to about 1100⁰C, in some embodiments, preferably in a range from about 925°C to about 1050⁰C. Likewise for the density step, the temperature typically is in a range from about 1100⁰C to about 1600⁰C, in some embodiments, preferably in a range from about 1200⁰C to about 1500⁰C. This heat treatment may occur, for example, by feeding the material directly into a furnace at the elevated temperature. Alternatively, for example, the material may be feed into a furnace at a much lower temperature (e.g., room temperature) and then heated to desired temperature at a predetermined heating rate. The heat- treatment can be conducted in an atmosphere other than air. In some cases it might be even desirable to heat-treat in a reducing atmosphere(s). Also, for, example, it may be desirable to heat-treat under gas pressure as in, for example, hot-isostatic press, or in gas pressure furnace.

[0046] In certain embodiments, the heat-treatment protocol may comprise at least two stages. The first stage comprising heating to a temperature near the first crystallization temperature (±50 degrees) of the glass and holding the temperature for at least 1 minute, 5 minutes, 20 minutes or even 1 hour to at least crystallize a portion of the glass. The second stage comprises heating at essentially any rate and encompassing temperatures higher than the first stage holding temperature. In some embodiments, the glass-ceramic can be cooled from the holding temperature of the first stage to about room temperature and then reheated in a second stage. In some embodiments, conducting heat-treatment in accordance with a two stage protocol has been found to reduce cracking and warpage of the article. In certain embodiments this target protocol is also beneficial for minimizing total heat-treatment time, thus improving manufacturability.

[0047] In some embodiments, the glass-ceramic first layer of the armor composite made according to methods of the present disclosure has a hardness of at least 13 (in some embodiments preferably, at least 14, 15, 16, 17, or even at least 18) GPa. In some embodiments, the glass-ceramic of the first layer made according to methods of the present disclosure has Young's modulus of at least 140 (in some embodiments at least 150, 175, 200, or even 250) GPa.

[0048] The first layer of the armor composite made according to methods of the present disclosure can be made in a variety of sizes and shapes, depending on the desired application. In some embodiments, the first layer of the armor composite has x, y, and z dimensions, each perpendicular to each other, and each of the x and y dimensions is at least 10 (in some embodiments 15, 20, 25, 50, 100, 500, or even 1000 or greater) millimeters. In some embodiments, the z dimension is at least 0.5 (in some embodiments 1, 2, 3, 5, 10, 25, or even 100) millimeters. In some embodiments, the shape of the first layer glass-ceramics is a hexagon or other shape that can be nested such that a plurality of glass-ceramic bodies can be laminated to second layer with minimal spacing between the glass-ceramic bodies.

[0049] The second layer of the armor composite comprises a force dissipating material. The force dissipating material can be any material known to those skilled in the art, including, for example, polycarbonate, polyacrylic (including cast acrylic, polymethylmethacrylate, modified acrylics and the like), cellulose acetate butyrate, ionomers, nylons, polyolefins, polyesters, polyurethane (thermosetting and thermoplastic), combinations thereof and the like. In some preferred embodiments, the force dissipating material comprises polyurethane, polyamid fibers (e.g., KEVLAR brand fiber available from DuPont), cast acrylic, polycarbonate, magnesium, aluminum, iron, and combinations thereof.

[0050] In some embodiments, the force dissipating material may also contain a protective hard coating on the surface opposite the bond material. The force dissipating layer typically ranges in thickness from 0.1 to 100 (in some embodiments, 0.5 to 50) millimeters thick. The force dissipating material may comprise a plurality of layers of the same or different materials bonded together to form a thicker layer.

[0051] The bond material used to affix the first layer to the second layer can be any bond material known to those skilled in the art, including, for example, polyurethane adhesives, polybutyl vinyl, thermosetting resins, UV curable resins, acrylic adhesives, combinations thereof, and the like.

[0052] The bond material can be applied uniformly across a substantial portion of the interface between the first and second layers, or can be applied to select portions of the interface. The bond material can be applied using application and/or laminating methods known to those skilled in the art.

[0053] In another embodiment of the present disclosure, the armor composite may further include additional layers, including, for example, a layer of silica based glass such as OEM safety glass, OEM tempered glass, float glass or any other suitable silica based glass.

[0054] EXAMPLES

[0055] Example 1

[0056] A porcelain jar was charged with 1000 g of DI water, pH of which was adjusted to 4 using HNO₃. Then the following oxide powders were added: 385g Al₂O₃, 33Og La₂O₃ , lOOg Gd₂O₃, and 185g ZrO₂ . The La₂O₃ powder was calcined at 700C for 6 hrs prior to batch mixing. About 2000 g of alumina milling media was added to the jar and the contents were milled for 72 hrs at 120 rpm. After milling, the resulting slurry was transferred into a glass beaker and stirred with a magnetic stirrer. Immediately after transferring the slurry into the beaker, 40 ml of 0.5M solution OfNH₄Cl was added which led to thickening of the slurry into a gel-like consistency. This gelatine-like substance was than transferred into glass trays and dried in forced convection air oven at 250F. The obtained dried powder cake was further calcined at 1250C for 2h to completely remove any residual moisture.

[0057] After grinding with a mortar and pestle, the resulting screened particles were fed slowly (about 0.5 gram/minute) through a funnel, under a argon gas atmosphere 5 standard liter per minute (SLPM), into a hydrogen/oxygen torch flame which melted the particles and carried them directly into a 19-liter (5 -gallon) rectangular container (41 centimeters (cm) by 53 cm by 18 cm height) of continuously circulating, turbulent water (20oC) to rapidly quench the molten droplets. The torch was a Bethlehem bench burner PM2D Model B obtained from Bethlehem Apparatus Co., Hellertown, PA. The torch had a central feed port (0.475 cm (3/16 inch) inner diameter) through which the feed particles were introduced into the flame. Hydrogen and oxygen flow rates for the torch were as follows. The hydrogen flow rate was 42 standard liters per minute (SLPM) and the oxygen flow rate was 18 SLPM. The angle at which the flame hit the water was approximately 90, and the flame length, burner to water surface, was approximately 38 centimeters (cm).

[0058] The resulting molten and quenched particles were collected in a pan and dried at 11OC. The particles were spherical in shape and ranged in size from a few tens of micron to up to 250 μm. From the fraction of beads measuring between 125 microns to 63 microns, greater than 95% were clear when viewed by an optical microscope. [0059] 5g of beads sized between 90 microns and 125 microns was placed in a graphite die (10 mm in diameter) and hot-pressed at 915C into a glass cylinder using 30 MPa of applied pressure. The glass cylinder was then sectioned into 1.2 mm thick disks that were polished to an optically smooth surface.

[0060] The hardness measurements were made using a conventional microhardness tester (obtained under the trade designation "MITUTOYO MVK-VL" from Mitutoyo Corporation, Tokyo, Japan) fitted with a Vickers indenter using a 500-gram indent load. The microhardness measurements were made according to the guidelines stated in ASTM Test Method E384 Test Methods for Microhardness of Materials (1991), the disclosure of which is incorporated herein by reference. The hardness values were averaged over 20 measurements. The average hardness was found to be 9.23 GPa +/- 0.12 GPa. [0061] Glass disks prepared in the current example were further subjected to heat- treatment at various temperatures between 950⁰C and 1250⁰C in order to induce crystallization and increase hardness. Heat-treatment was conducted using a dilatometer available from Netzsch Instruments, SeIb, Germany under the trade designation "NETZSCH STA 409 DTA/TGA". Sample is placed in an Al₂O₃ sample holder and heated in static air at 10°C/minute, from an initial temperature (e.g. room temperature, or about 25°C) to a final temperature, such as 950⁰C.

[0062] Hardness was measured at each annealing temperature. The results are shown in Table 1.

[0063] Table 1

[0064] Example 2

[0065] About 200 g of beads was prepared as described in Example 1. 150 g of beads with fraction between 125 and 63 micrometers was placed into a 3 x 3" square die and hot- pressed at 925C under 20 MPa of applied load. The resultant material was a glass plate with thickness of about 6 mm. Hardness was determined to be 9.1 GPa +/-0.13 GPa. [0066] The glass plate was secured in an aluminum frame holder with silicone rubber seal between the glass plate and the aluminum frame. The exposed area of the piece was 6.35 cm x 6.35 cm (2.5 x 2.5 inches). The thickness of the piece was 6 mm. This sample was tested using a 9 mm gas gun (rated to 1200 psi, manufacturer Physics Applications Inc. Dayton, Ohio). The projectile was a full metal jacket 9 mm round. The distance between the glass plate and the gun barrel's exit was 2.13 m (7 feet). The speed was measured with a "Model 35" Oehler chronograph (Oehler Research, Inc., Austin Texas). The speed measured was 850 feet per second. The glass plate broke upon impact but the projectile was stripped of its jacket, flattened and fragmented. The projectile was slowed down enough to be caught inside of a cardboard box behind the target holder. [0067] It is to be understood that even in the numerous characteristics and advantages of making armor composites set forth in above description and examples, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes can be made to detail, especially in matters of glass-ceramic composition within the principles of the invention to the full extent indicated by the meaning of the terms in which the appended claims are expressed and the equivalents of those structures and methods.

Claims

WHAT IS CLAIMED IS:

1. A composite material comprising: a first layer comprising a glass-ceramic comprising a first metal oxide selected from the group consisting OfAl₂O₃, CaO, CoO, Cr₂O₃, CuO, Fe₂O₃, HfO₂, MgO, MnO, Nb₂O₅, NiO, REO, Sc₂O₃, Ta₂O₅, TiO₂, V₂O₅, Y₂O₃, ZnO, ZrO₂, and complex metal oxides thereof, and a second metal oxide selected from the group consisting OfAl₂O₃, Bi₂O₃, CaO, CoO, Cr₂O₃, CuO, Fe₂O₃, Ga₂O₃, HfO₂, MgO, MnO, Nb₂O₅, NiO, REO, Sc₂O₃, Ta₂O₅, TiO₂, V₂O₅, Y₂O₃, ZnO, ZrO₂, and complex metal oxides thereof, wherein the first metal oxide and the second metal oxide are different from one another, wherein the glass-ceramic comprises a hardness of at least 13 GPa, wherein the glass-ceramic has x, y, and z dimensions each perpendicular to each other, and each of the x and y dimensions is at least 10 millimeters, and wherein the glass-ceramic contains not more than 20 percent by weight SiO₂, not more than 20 percent by weight B₂O₃, and not more than 40 percent by weight P₂O₅, based on the total weight of the glass-ceramic; a second layer comprising a force dissipating material; and a bond material that affixes at least a portion of the first layer to the second layer.

2. The composite material of claim 1 wherein the first metal oxide is selected from the group consisting Of Al₂O₃, REO, TiO₂, Y₂O₃, ZrO₂, and complex metal oxides thereof.

3. The composite material of claim 1 wherein the glass-ceramic comprises not more than 20 percent by weight collectively B₂O₃, GeO₂, P₂O₅, SiO₂, TeO₂, and combinations thereof, based on the total weight of the glass-ceramic.

4. The composite material of claim 1 wherein the force dissipating material comprises a material selected from the group consisting of polycarbonates, polyacrylics, cellulose acetate butyrate, nylon, polyolefins, polyesters, polyurethanes, and combinations thereof.

5. The composite material of claim 1 wherein the force dissipating material comprises a material selected from the group consisting of polyurethane, polyamid fibers, cast acrylic, polycarbonate, magnesium, aluminum, iron, and combinations thereof.

6. The composite material of claim 1 wherein the bond material comprises a material selected from the group consisting of polyurethane adhesives, polybutyl vinyl, thermosetting resins, UV curable resins, acrylic adhesives, and combinations thereof.

7. The composite material of claim 1 wherein the glass-ceramic comprises a non- glass material selected from the group consisting of crystalline metal oxides, metal carbides, metal nitrides, metal borides, and diamond.

8. The composite material of claim 1 wherein the glass-ceramic has a hardness of at least 15 GPa.

9. A method of making a composite transparent material comprising: providing a plurality of glass bodies comprising a first metal oxide and a second metal oxide, wherein the first metal oxide and the second metal oxide are different from one another, the glass bodies having a T_g and T_x, wherein the difference between T_g and T_x is at least 5 degrees Celsius, and wherein the glass bodies contain not more than 20 percent by weight SiC^, not more than 20 percent by weight B₂O3, and not more than 40 percent by weight P₂O5, based on the total weight of the glass bodies; heating the glass bodies above the T_g and coalescing at least a portion of the plurality of glass bodies to provide a bulk glass body; heat-treating the bulk glass body to form a glass-ceramic; providing a force dissipating material; applying a bond material to at least one of the glass-ceramic and the force dissipating material; and laminating the glass-ceramic and the force dissipating material.

10. The method of claim 9 wherein the first metal oxide and second metal oxide are selected from the group consisting of AI₂O₃, B1₂O₃, CaO, CoO, Cr₂θ₃, CuO, Fe₂θ₃, Ga₂O₃, HfO₂, MgO, MnO, Nb₂O₅, NiO, REO, Sc₂O₃, Ta₂O₅, TiO₂, V₂O₅, Y₂O₃, ZnO, ZrO₂, and complex metal oxides thereof.

11. The method of claim 9 wherein the glass-ceramic comprises not more than 20 percent by weight collectively B₂O₃, GeO₂, P₂O₅, SiO₂, TeO₂, and combinations thereof, based on the total weight of the glass-ceramic.

12. The method of claim 9 wherein the bond material comprises a material selected from the group consisting of polyurethane adhesives, polybutyl vinyl, thermosetting resins, UV curable resins, acrylic adhesives, and combinations thereof.

13. The method of claim 9 wherein the force dissipating material comprises a material selected from the group consisting of polycarbonates, polyacrylics, cellulose acetate butyrate, nylon, polyolefins, polyesters, polyurethanes, and combinations thereof.

14. The method of claim 9 wherein the force dissipating material comprises a material selected from the group consisting of polyurethane, polyamid fibers, cast acrylic, polycarbonate, magnesium, aluminum, iron, and combinations thereof.

15. The method of claim 9 wherein the glass-ceramic comprises a non-glass material selected from the group consisting of crystalline metal oxides, metal carbides, metal nitrides, metal borides, and diamond.

16. A method of making a composite transparent material comprising: providing a glass-ceramic comprising a first metal oxide selected from the group consisting OfAl₂O₃, CaO, CoO, Cr₂O₃, CuO, Fe₂O₃, HfO₂, MgO, MnO, Nb₂O₅, NiO, REO, Sc₂O₃, Ta₂O₅, TiO₂, V₂O₅, Y₂O₃, ZnO, ZrO₂, and complex metal oxides thereof, and a second metal oxide selected from the group consisting OfAl₂O₃, Bi₂O₃, CaO, CoO, Cr₂O₃, CuO, Fe₂O₃, Ga₂O₃, HfO₂, MgO, MnO, Nb₂O₅, NiO, REO, Sc₂O₃, Ta₂O₅, TiO₂, V₂O₅, Y₂O₃, ZnO, ZrO₂, and complex metal oxides thereof, wherein the first metal oxide and the second metal oxide are different from one another, wherein the glass-ceramic comprises a hardness of at least 13 GPa, wherein the glass-ceramic has x, y, and z dimensions each perpendicular to each other, and each of the x and y dimensions is at least 10 millimeters; providing a force dissipating material; applying a bond material to at least one of the glass-ceramic and the force dissipating material; and laminating the glass-ceramic and the force dissipating material.

17. The method of claim 16 wherein the glass-ceramic comprises not more than 20 percent by weight collectively B₂O3, GeC^, P₂O5, SiC^, TeO₂, and combinations thereof, based on the total weight of the glass-ceramic.

18. The method of claim 16 wherein the bond material comprises a material selected from the group consisting of polyurethane adhesives, polybutyl vinyl, thermosetting resins, UV curable resins, acrylic adhesives, and combinations thereof.

19. The method of claim 16 wherein the force dissipating material comprises a material selected from the group consisting of polycarbonates, polyacrylics, cellulose acetate butyrate, nylon, polyolefins, polyesters, polyurethanes, and combinations thereof.

20. The method of claim 16 wherein the glass-ceramic comprises a non-glass material selected from the group consisting of crystalline metal oxides, metal carbides, metal nitrides, metal borides, and diamond.