Newbies_Kid Posted January 20, 2011 Share Posted January 20, 2011 I have a piece of Alumina (Al203) to be coated with metallic multilayer of Cu-Al-Ti. I choose to use evaporation method instead of Plasma sputtering because some books says Plasma sputtering PVD cause some impurities incorporated in thin coating.. So my problem is to find the phase transition diagram of those metals because i need to know the pressure and the temperature at which the solid metals start to vaporize.. Just their critical point (P-T diagram) would also be helpful.. Thanks ... Link to comment Share on other sites More sharing options...
CaptainPanic Posted January 26, 2011 Share Posted January 26, 2011 The weird thing is that solids already have a vapor pressure. In the case of metals, that's just incredibly low (so low that we can't measure it). The question you must be asking is what vapor pressure you want to have, and at what temperature this is reached. I googled for [vapor pressure titanium], and I got a hit. however, it was not for free, so I can't give you the answer. The information is out there. I have experienced that very often a data set for vapor/liquid equilibria are described in a different paper than liquid/solid... and again in a different publication than vapor/solid. So, to search for the entire phase diagram is maybe too ambitious. Try instead to search for the individual equilibrium lines, and construct the diagram yourself. Good luck! 1 Link to comment Share on other sites More sharing options...
John Cuthber Posted January 26, 2011 Share Posted January 26, 2011 Well, because there's a gadget called the "Titanium sublimation pump" the data fro titanium is sort of available Have a look here http://cas.web.cern.ch/cas/Baden/PDF/Vacuum.pdf It says they run the pumps at about 1300C. I also have a charming old book called "Handbook of electron tube and vacuum techniques" It lists the temperatures for evaporating a bunch of metals (i.e. where the pressure reaches 10µ of mercury) Al 996C Cu 1273C and Ti 1546C Apart from the Ti, those temperatures are above the melting points of the metals which means you will be boiling them, rather than subliming them. I don't know if that will matter. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now