Binary phase diagrams - understanding the eutectic point

[Femme_physics]

1) So, does the binary phase always represent the materials 100% on each end? That is to say, if you have lead and antimony, the right side will always represent 100% of one of the two, and the other side will present 100% of the other. If we look in the middle of the diagram, it's 50-50%, right?

2) The eutectic point is basically an ideal point on the diagram that represents the lowest cooling point based on the certain percentages of each materials. This is a tested value.


Do I have it correctly?

[Mapes]

1) So, does the binary phase always represent the materials 100% on each end? That is to say, if you have lead and antimony, the right side will always represent 100% of one of the two, and the other side will present 100% of the other. If we look in the middle of the diagram, it's 50-50%, right?

Yes, but it might be 50%-50% by weight percent or by atomic percent. A complete phase diagram will tell you which one is being used. Some diagrams have one scale on the bottom x axis and the other on the top (see here (http://www.interfluxusa.com/images/Eutectic_graf.jpg), for example).

2) The eutectic point is basically an ideal point on the diagram that represents the lowest cooling point based on the certain percentages of each materials. This is a tested value.

The eutectic point is the temperature and composition that marks the lowest temperature at which the solution can be entirely liquid.

[Femme_physics]

Yes, but it might be 50%-50% by weight percent or by atomic percent. A complete phase diagram will tell you which one is being used. Some diagrams have one scale on the bottom x axis and the other on the top (see here, for example).

Ah, I see.

The eutectic point is the temperature and composition that marks the lowest temperature at which the solution can be entirely liquid.

Is a better way to put it :)

Thanks a bunch Mapes.

BTW - I've been wondering for a while now, what does your avatar represent?

[Mapes]

BTW - I've been wondering for a while now, what does your avatar represent?

It's meant to represent chemical-mechanical coupling: a melding of schematics for forces, springs, atomic force microscopy, nanoindentation, mortar & pestle, and ligand-receptor binding. Thx for asking!