US Government As Represented by the Secretary of the Army

Gary A Gilde

Parimal J Patel

Louise C Sengupta

Steven Stowell

Eric Ngo

Robert Lancto

James W McCauley

David M Spagnuolo

William J Croft

Thomas V Hynes

Clifford Hubbard

Robert J Pavlacka

Terrence M Taylor

Constantine Fountzoulas

Brian Pothier

Jerry C Lasalvia

Joe Wells

Methods of preparing boron suboxide are provided herein. In some embodiments, a method for preparing boron suboxide may include loading elemental boron powder into a furnace; purging the furnace by flowing a first gas comprising one of nitrogen or an inert gas into the furnace; heating the boron powder in a reactive atmosphere comprising a mixture of argon and a non-reducing oxygen-containing gas to convert elemental boron powder into boron suboxide powder, wherein the amount of oxygen in the reactive atmosphere is no greater than about 1%.

Method for synthesis of boron suboxide

A transparent armor construction having a laminate structure with at least two layers. The layers are constructed of two different materials selected from the group of glass, ceramic, resin, polymeric material, and plastic and in which the at least two layers include different coefficients of thermal expansion. The layers are bonded together and a planar frame having an open central section and an outer border is then bonded to the laminate structure. The material for the planar frame is selected so that it has a coefficient of thermal expansion less than the coefficient of thermal expansion of the laminate layer to which it is bonded.

Transparent armor construction

A dense polycrystalline aluminum oxynitride body is produced. According the method of production, aluminum oxide (alumina) powder and 26 to 40 mole % aluminum nitride powder is mixed to form a very fine powder mixture. The powder mixture is shaped and hot pressed at a moderate temperature, preferably about 1600&#xb0; C., which is below the temperature of aluminum oxynitride (AlON) formation to produce a dense intermediate body. The dense intermediate body is reacted to produce a highly dense polycrystalline aluminum oxynitride body. The dense body is particularly useful for ballistic armor.

Method for making dense polycrystalline aluminum oxynitride

A transparent aluminum oxynitride product is produced by a first heat treating step wherein a combination of AlOand AlN at a temperature within the solid-liquid phase and a second step of sintering the heat treated combination at a temperature at least 50&#xb0; C. less than the heat treating temperature. The method introduces a small fraction of liquid that aids in pore elimination and densification. In a single step, the material is shifted from the liquid/solid region into a solid AlON solution region, wherein the liquid is fully reacted with the solid AlON phase, with further sintering occurring. The procedure is sufficient to eliminate voids and other imperfections which often result in a reduction in optical clarity.

Transient liquid phase reactive sintering of aluminum oxynitride (AlON)

A ceramic nanocomposite made from silicon, oxygen and nitrogen is provided hich has a very low dielectric constant, low dielectric loss along with good strength and hardness. The ceramic nanocomposite finds use in millimeter-wave radomes and microwave radomes used on aircraft which must resist erosion from high speed impact with water, ice and dust in the atmosphere.

Sion low dielectric constant ceramic nanocomposite

A novel ceramic ferroelectric material having a low dielectric constant, loss and high tunability. The material is a composite comprising Barium Strontium Titanate (BSTO) and a ceramic material having a low dielectric constant. The preferred composite is represented by Ba.sub.1-x Sr.sub.x TiO.sub.3 -Al.sub.2 O.sub.3, wherein x is greater than 0.00, but less than or equal to 0.70, and wherein the percent weight ratio between Ba.sub.1-x Sr.sub.x TiO.sub.3 and Al.sub.2 O.sub.3 ranges from approximately 99%-40% and 1%-60%, respectively. The novel materials possess superior electronic properties; and they may be employed in various antenna systems.

Ceramic ferroelectric material

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North East, MD, United States of America

Gary A Gilde