duncanstives

Very interesting... Apparently your right: They do! This is not intuitive and I have worked with many vacuum systems and never seen this phenomenon but of course have never tried to make it happen and any places where two parts are joined in vacuum systems would have some sort of butyl rubber seal rather than metal to.metal contact... You've also explained a phenomenon I just remembered: I have worked with a partial pressure hydrogen firing furnace that uses hydrogen forming gas and high temperatures to removed surface oxides... Often times stainless parts stick together a little after firing... I always wondered about it because the process is certainly below the melting point of the stainless... I bet they're welding together a bit. Thanks for that link... Explains a lot!

Ok this is driving me nuts... Metals are generally held together by metallic bonds where they all share a big cloud of electrons (I know this isn't totally accurate and of course there are exceptions but bear with me for the sake of argument)... I also know that metals (with the exception of certain amorphous solids like the SIM door tool for the iPhone 3gs) are organized in a specific pretty dense crystalline structure... My question is, since metallic bonds are pretty flexible with the whole electron cloud thing, what prevents two pieces of solid metal from becoming one at room temperature? I know surface morphology, oxidation layers and a bunch of stuff would prevent it under normal conditions... But if I were to somehow machine two pieces of steel using some process that made them truly flat (at an atomic level) and press them together in a perfect vacuum (also having ensure that my smoothed surface never was exposed to oxygen)what would keep the stupid things from randomly starting to share electrons back and forth thus effectively becoming one piece of solid material? Is it just because the faces would not be organized in the neat lattice and thus would be effectively not close enough for the metallic bond to be very strong? That still doesn't quite seem right because if I apply voltage across my two pieces of metal the electrons will have no problem travelling from one face to the other... Even a very small voltage would work... This is driving me nut... Somebody please help!