Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!dimacs.rutgers.edu!aramis.rutgers.edu!athos.rutgers.edu!nanotech From: osan@cbnewsb.cb.att.com (andrew.vida-szucs) Newsgroups: sci.nanotech Subject: Re: Diamonds? Keywords: diamonds, bones Message-ID: Date: 12 Apr 91 21:20:42 GMT Sender: nanotech@athos.rutgers.edu Organization: AT&T Bell Laboratories Lines: 33 Approved: nanotech@aramis.rutgers.edu In article toms@fcs260c2.ncifcrf.gov (Tom Schneider) writes: > >I was reading one of Drexler's papers in the Nanocon 1989 proceedings, where he >notes the possibility of creating diamond for structural components. So I >began to think of a shark with diamond tipped teeth. Wouldn't that have an >advantage over calcium? Wouldn't a diatom or shrimp encased in diamond be able >to survive better? So why don't living things use diamond? Or do they? If >they don't, is this telling us something about the limits of nanotechnology? >That is, maybe diamond can ONLY be made at high pressures and/or temperatures, >so a molecular machine couldn't do it, unless the machine operated under those >conditions. > There are chemical deposition methods for creating artificial diamonds that require *no* high pressure conditions whatsoever. In fact they require partial vacuum conditions which may explain why it does not occur in living organisms. These techniques use (i believe) methane gas as the carbon source. They were initially developed by Exxon oh, maybe 20 years ago but only in the past year or so have they been refined to the point where they are commercially viable. There was an article in the Wall Street Journal several months back. It seems that just about *any* shape can be produced using this method. I don't (though am not sure) think that this method will produce gem quality stones, so don't rush out to get your equipment. There is one creature I know of that has *carbide* teeth. It is some sort of animal in a shell whose name I forget at the moment and in its mouth there is a circle of small rectangular (Tungsten??) carbide teeth that it uses to grind away at the reef on which it lives. They exist somewhere in the South Pacific maybe Polynesia or where have you. Any how, that's about it regarding my knowledge of synthetic diamond.