Hi, Could anyone tell me the latent heat of fusion and vapourisation of Brass.
Better still, where can I find such data. The net has proved futile and most databooks Ive referred to dont have this particular piece of information.
Cheers, Nauzad
You must look for thermodynamic data of the binary phase diagram copper-zinc.
Michael Dahms
Collected tables for a wide variety of alloys is not trivial to find. I'm sure there is one in a library somewhere, but in the mean time I found that "brass" (No exact composition, but I can only assume that simply brass would refer to 33%zinc or at least give a number that is in the ballpark) has a latent heat of 168kJ/kg. This number was taken from: "Engineering Formulas" by Kurt and Reiner Gieck, 7th Edition
I just had it laying around, but it didn't have a very extensive table. Just in case you didn't know, if you can find either the heat of vaporization or the heat of sublimination you can calculate the remaining heat. (Hfusion + Hvaporization = Hsublimination)
Seth
A good starting point should be the ASM Handbook of Binary Phase Diagrams. And there's the world of CALPHAD.
Michael Dahms
I did check the ASM handbook. But Im not very thorough in Chemistry.
Could you tell me how to determine the latent heats from a Phase diagram (I thought it could only provide the melting points of the material at different compositions).
PS: I need the latent heat of vapourisation too. Would the phase diagram help to determine that too.
Nauzad
No.
You should check the according text and the references.
Michael Dahms
Well, lines on a phase diagram correspond to equality between chemical potentials. They in turn could be related to enthalpies.
You can start with the simplest case: vaporization of a one-component system. Then the saturated pressure is related to enthalpy as
ln p = - DelH/RT + DelS
Similar but more compilcated equations could be written for multi-component phase diagrams.
The best way is to use specialized databases with Gibbs energies, see for example Thermocalc (unfortunately not free). Provided your system is included you can obtain on-line complete information including phase diagrams and all thermodynamic properties.
You can find some background info and references in the manual of my software for computational thermodynamics
Evgenii Rudnyi
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.