george koller on mon 21 oct 02
Hello All,
This thread and list has been fascinating to me and I
eagerly added to it remembering seeing a blue body
armor vest on display "somewhere" during my gig at
Alfred, but it has been bothering me that I could not
remember much more. So I have done a little search
and found this somewhat related information. While
Ceramic materials may not be the primary material
in these things at least I now know I wasn't picking this
out of the air somewhere....
Body Armour
CONFORMABLE BODY ARMOR MADE BY SHAPE FORMING OF LAMINATED CERAMIC TAPES
The development of ceramic armor has been studied for several years in an attempt
to identify a high-performance, lightweight armor material that allows for
increased speed and mobility for both personnel and vehicles. Ceramic armor,
typically Al2O3, SiC, or B4C, is presently being fabricated commercially and is
primarily used to blunt armor piercing projectiles which are then defeated by more
conventional armor that backs the ceramic material. Current research trends in
armor development are to lightweight, to improve ballistic performance, and to
extend armor protection to body extremities. Ceramic Composites, Inc. (CCI) is
researching surface strengthening of ceramic armor via continuous fiber
reinforcement, a concept which has demonstrated the potential for improved
ballistic performance and multi-hit capability. Incorporation of the ceramic fiber
reinforcement is made possible by ceramic tape lamination. This process allows for
designed architectures which, through graded structures, avoids the issue of
impedance mis-match, and also allows for the incorporation of surface compressive
forces due to the CTE variations in the materials' system. Controlling the armor
architecture in such a way should allow the development of lightweight armor with
improved ballistic performance. Work is underway to design armor having an areal
density of less than 5PSF.
The development of conformable body armor for body extremities is presently
underway at CCI. This requires shape forming of parts to conform to the body such
that joint mobility is not sacrificed. CCI is utilizing conventional metal forming
techniques to mold fiber reinforced green ceramic laminated tapes to fit the
contours of the body. Initial research has demonstrated the formation of curved
components having thicknesses of 0.1". The process has been used to form Al2O3 and
composite SiC/Si3N4 laminated tapes, as well as a continuous SiC fiber reinforced
SiC/Si3N4 materials system. A debinding and sintering cycle has been developed to
densify these shaped structures, without shape distortion, via pressureless
sintering. Having demonstrated the shape forming capability of laminated ceramic
tapes, CCI will now focus the development of this technology on the fabrication of
armor for body extremities. A preferred materials system for ballistic performance
will be identified, tape casting compositions for that materials system will be
formulated, and the shape forming process will be optimized. This technology holds
great potential for fabricating ceramic armor for applications such as shoulder and
elbow protection.
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