Path: spln!rex!dex!extra.newsguy.com!lotsanews.com!news.maxwell.syr.edu!news-out.visi.com!hermes.visi.com!gemini.tycho.net.POSTED!not-for-mail From: gherbert@gw.retro.com (George William Herbert) Newsgroups: sci.military.moderated Subject: Re: Boron Carbide in Armor Date: 30 Dec 2001 20:24:32 -0800 Organization: Dis- Approved: sci-military-moderated@retro.com Message-ID: <a0opa0$j56$1@gw.retro.com> References: <a0of5f0odr@enews1.newsguy.com> Lines: 50 NNTP-Posting-Host: 73b3878f.newsreader.tycho.net X-Trace: 1009771687 gemini.tycho.net 79562 205.179.181.194 X-Complaints-To: abuse@tycho.net Xref: spln sci.military.moderated:41483 TTK Ciar <ttk@NOSPAM_remove_all_after_org.ciar.org.motorola.com> wrote: > I was hoping someone could clarify something for me. > > According to usenet message <ECLMAA.H2L@ranger.daytonoh.ncr.com> >(from 1997), the T-80B's armor ("second-generation combination K") >was partially composed of a layer of Boron Carbide suspended in a >plastic resin (I think that's what he's saying?). > > Sites like http://www.ceradyne.com/apdef.htm which advertise >armor products (applique, flak vests, et al) made with Boron Carbide >all present them as sheets of hot-pressed solid BC. (Which makes >sense to me, since it's the hardness you want.) > > Does anyone know why the Russians were making their armor a >composite of BC and plastic, instead of solid BC? Or am I just >reading the guy's post wrong? Perhaps they were sandwiching solid >layers of BC between solid layers of plastic spacers? There are three uses of ceramics in armor systems, depending on the armor system type. There's "face-hardening"; use in flak vests and applique, where the primary role of the ceramic layer is to shatter the incoming shot or shell so that it doesn't penetrate the remaining armor as an intact solid body. There's "bulk" ceramic armor, where it's used as a solid block intended to both shatter and then absorb the fragments. This has proved extremely difficult for tank-armor KEAP defeat roles, it's more effective than RHA but is expensive and hard to manufacture etc. Then there are the Russian controlled deformation type armors, and possibly western composite armors as well, where layers of often ceramic armor are non-rigidly mounted within an armor box, and can absorb both energy (due to hardness and strength) and to some extent momentum (due to ability to deform, move, or shift within the armor system). We know that the Russians have used both bulk ceramics (sintered alumina inserts in some T-64, T-72 models for example) and controlled deformation using metallic inserts and plastic foam spacers. I believe the current best guess about the late T-80 armor systems and T-90 armor systems is that they're controlled deformation using BN inserts. -george william herbert gherbert@retro.com