Latent heat of Brass (Cu66%, Zn33%)

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
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Nauzad wrote:

You must look for thermodynamic data of the binary phase diagram copper-zinc.
Michael Dahms
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Michael Dahms wrote:

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
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Seth Imhoff wrote:

A good starting point should be the ASM Handbook of Binary Phase Diagrams. And there's the world of CALPHAD.
Michael Dahms
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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
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Nauzad wrote:

No.
You should check the according text and the references.
Michael Dahms
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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
http://evgenii.rudnyi.ru/soft/tdlib00+/doc/00tdlib.pdf
Best wishes,
Evgenii Rudnyi
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