What are lead alloys compared with lead mixtures?

[Naphtali]

I have been informed that there are lead-based casting compositions that are true alloys rather than mixtures. What is the difference between the two? How or why is the difference significant? And lastly, what are these alloys?

[fourarmed]

In this case, "alloy" and "mixture" mean the same thing: a combination of materials that do not form a molecular compound. I imagine your informant was thinking of eutectic mixtures when he referred to "true" alloys. Strictly speaking, the term "eutectic" refers to a temperature - the lowest temperature at which the liquid form of an alloy is in equilibrium with its solid state. In practice, any alloy that has a specific melting point is said to be eutectic.

[AZ-Stew]

These Wikipedia articles should just about cover it:

http://en.wikipedia.org/wiki/Alloy

http://en.wiktionary.org/wiki/homogeneous?rdfrom=Homogeneous

http://en.wikipedia.org/wiki/Mixture

http://en.wikipedia.org/wiki/Type_metal

Regards,

Stew

[Calamity Jake]

Pure lead is just that pure lead or as pure as the foundry can make it.
Any other elemant mixed with the lead makes it an alloy and or mixture, in this instance they mean the same thing.
There are many different elemants that can be alloyed with lead, the most common are tin, aresnic, antimony, silver, copper and cadmium to name a few.
Lead alloy application dictates what elemants are used to create that alloy.

[ForneyRider]

Lead oxides and lead sulphates are common in lead.

I found these 2 resources on Google books. They are free and not too bad a read.

Annual_Report_of_the_State_Mineralogist_.pdf

Handbook_of_Metallurgy.pdf

[Firebird]

What we use for casting are lead alloys, the metals (lead, tin, antimony, arsenic) will NOT separate on their own. Mixtures WILL separate, when a pot gets contaminated with Zinc, it forms a mixture that with time will allow a pool of molten zinc to form on top of the lead. A very small amount of zinc will alloy with the lead, but most of it will separate out and form a pool on top. Some babbit metals are actually mixtures of copper and lead, if not thoroughly mixed right before pouring the lead and copper separate.

[largom]

Firebird is right on. Our alloys of lead, tin, and antimony DO NOT readily seperate.
A mixture will seperate such as muddy water. Let it sit still long enough and the mud [dirt] will seperate and settle to the bottom. Other mixtures may seperate and one component float.
Larry

[felix]

Everything separates, including the so-called compounds, given correct circumstances. Even atoms, once thought of as bottom-most entities, seperate. Sooner or later scientists will realize, or extrapolate, that nothing is "small" enough, all the way down to zero (as the limit). Just like the Universe in the opposite direction. It's big to us, and as it contains everything as one unit (as the limit). That is what the Lord intended, as He is the Alpha and the Omega, letters for the beginning and the end in Greek. Everything physical has a shelf life, as termed by the EPA, and is a great observation on their part. Find and check the inner circle on the body side of your tires, which has at least four numbers in the circle: the month and the year of manufacture. Example: xyz0102 in the circle: manufacturing plant (xyz), first week (01) in 2002 (02). Typical tire rubber typically is too dry to drive on (hiway) when the tire is over 7 years old. ... felix