Abstract:
A boron carbide body having a graphite content in which the central portion of the body includes more graphite that the region surrounding the central portion and adjacent the exterior surface thereof, and a method for fabricating the boron carbide body.
Abstract:
The invention provides a process for manufacturing high density boron carbide by pressureless sintering, enabling to create sintered products of complex shapes and high strength. The process comprises mixing raw boron carbide powder with carbon precursor, such as a polysaccharide, compacting the mixture to create an object of the desired shape, and finally carbonizing and sintering the object at higher temperatures.
Abstract:
A boron carbide composite body produced by an infiltration process that possesses high mechanical strength, high hardness and high stiffness has applications in such diverse industries as precision equipment and ballistic armor. In one embodiment, the composite material features a boron carbide filler or reinforcement phase, and a silicon carbide matrix produced by the reactive infiltration of an infiltrant having a silicon component with a porous mass having a reactable carbonaceous component. In an alternate embodiment, the infiltration can be caused to occur in the absence of the reactable carbonaceous component, e.g., to produce "siliconized boron carbide". Potential deleterious reaction of the boron carbide with silicon during infiltration is suppressed by alloying or dissolving a source of boron, or a source of carbon, or preferably both boron and carbon into the silicon prior to contact of the silicon infiltrant with the boron carbide. In a preferred embodiment of the invention related specifically to armor, good ballistic performance can be advanced by loading the porous mass or preform to be infiltrated to a high degree with one or more hard fillers such as boron carbide, and by limiting the size of the morphological features, particularly the ceramic phases, making up the composite body. The instant reaction-bonded boron carbide (RBBC) composite bodies are at least comparable in ballistic performance to current boron carbide armor ceramics but feature lower cost and higher volume manufacturing methods, e.g., infiltration techniques.
Abstract:
Zur Herstellung einer B/N/C/Si-Keramik wird als Borazineprecursor B-tris(silylvinyl)borazin pyrolysiert. Nach einer Vorpyrolyse wird durch eine weitere Pyrolyse bei höheren Temperaturen eine Hochtemperaturkeramik erhalten, die sehr rein und im Wesentlichen porenfrei ist. Die Keramik ist zudem weitgehend sauerstofffrei und eignet sich insbesondere als Beschichtungsmaterial und zur Herstellung von Heizelementen.
Abstract translation:以制备B / N / C / Si的陶瓷作为Borazineprecursor B-三(silylvinyl)环硼氮烷进行热分解。 后一个prepyrolysis通过进一步的热解在较高温度下,高温陶瓷,这是非常纯的和基本上无孔的而获得。 陶器也基本上无氧气的并且尤其适合作为涂层材料和用于生产加热元件。
Abstract:
Die Erfindung betrifft einen Metall-Keramik-Verbundwerkstoff mit einer keramischen Matrix und einer metallischen Phase, die voneinander durchdrungen sind, die zusammen einen nahezu dichten Körper bilden und an Grenzflächen miteinander in Berührung stehen. Die Erfindung zeichnet sich dadurch aus, dass der Verbundwerkstoff zwischen der metallischen Phase und der keramischen Phase eine Zwischenschicht aufweist, die Zwischenschicht eine Dicke zwischen 10 nm und 100 nm aufweist und aus Reaktionsprodukten der metallischen Phase und der keramischen Phase besteht.
Abstract:
The present invention relates to a method for producing agglomerated boron carbide. One form of the present invention includes the steps of providing a boron carbide powder precursor having particle sizes smaller than about 1 micron in diameter, mixing the boron carbide powder precursor with binder solution to form a slurry, drying the slurry to yield a solid residue, crushing the solid residue to yield green boron carbide particles, and firing the green boron carbide particles. The resultant agglomerated boron carbide particles have diameters generally ranging from about 5 to about 30 microns. The agglomerated boron carbide particles are characterized as boron carbide grains of about 1-2 microns in diameter suspended in a vitreous boron oxide matrix.
Abstract:
A method for casting high definition bodies from boron carbide suitable for sintering including the steps of mixing boron carbide particles with an aquaeous binder system to form a homogenised mixture forming the mixture into the required shape and drying the mixture. The cast bodies when sintered may amongst other applications be used for high impact resistance such as body armour and in wear and corrosion resistance.
Abstract:
A composite material with a matrix produced by sequenced chemical vapour infiltration within a fibrous reinforcement. Each basic matrix sequence includes a relatively flexible layer and a relatively rigid ceramic layer and has a thickness that increases away from the reinforcement fibres. The thickness of at least the first sequence to be deposited is small enough to enable essentially individual sheathing of the fibres. The flexible layers are made of an anisotropic material having sufficient shear and transverse resiliency, and the thickness of the flexible layers is large enough to maintain the mainly ceramic nature of the matrix while absorbing the differential expansion of the components of the composite material during the production thereof, without giving rise to an initial cracking network.
Abstract:
A method to at least partially impregnate a porous ceramic body with a metal comprising positioning a sacrificial porous ceramic transport means in physical contact with the metal and between the porous ceramic body to be impregnated and the metal; interposing a sufficient amount of a ceramic powder in contacting relationship between the ceramic body and the transport means to enable the metal to flow from the ceramic transport means to the ceramic body and insufficient to permit metal bonding between the transport means and the ceramic body, at least one constituent of the powder being wettable by, and chemically reactive with the metal; and maintaining at least the ceramic body and metal transport means at a temperature, and for a time, sufficient for at least a portion of the metal to flow through the transport means and into the ceramic body to impregnate the ceramic body a predetermined amount to form a metal impregnated ceramic body of near net shape.