Improved Processing of Armor Ceramics for Reduced Emissions of VOC's and Greenhouse Gases.

摘要

The use of armor ceramics by U.S. military forces is increasing. The manufacture of armor ceramics requires extensive use of energy, raw materials, capital equipment and consumables. The environmental impact of processing these materials is considerable in terms of produced green house gases, the release of volatile organic compounds (VOC s), and the consumption of natural resources. The industry needs to identify which steps in the processing route can be modified to prevent pollution without affecting the function of the materials. Common armor ceramics materials are Boron Carbide (B4C), Silicon Carbide (SiC), Tungsten Carbide (WC), Aluminum Nitride (AlN), and Aluminum Oxide (Al2O3). Of these materials B4C and SiC are of the most immediate interest in the industry due to their low densities and high hardness. B4C is used as the hard face for SAPI (Small Arms Protective Inserts) bulletproof vests (6 lbs each) for the Marine Corps and Army's Interceptor Body Armor Systems and in the protection system of all USA rotor wing aircraft, while SiC is being tested for armor systems in future land vehicles. It is projected that each vehicle will use 2-3 tons of ceramic armor. Cercom is a leading manufacturer of armor ceramics and makes a broad range of armor ceramics by hot pressing. This process produces the necessary fine grain microstructure, full density, and good mechanical properties in covalently bonded carbides and nitrides required for armor ceramics. Both net shape components such as plates and vests and machinable blanks can be manufactured by hot pressing. For production of net shape components the part is first formed into a green body using blended powder and then densified, while for machinable blanks the blended powder is pre-compacted in a graphite mold and densified. The process for making blended powders depends on the type of powder used and the sintering aids added to it.