brass and nickle silver

[nkp_174]

The dissolution of salt in water: This seems like a physical change because we know we can recover the salt from the water. However, if we look at the microscopic level, we see that the two types of atoms in salt, sodium and chlorine, separate from one another. In this example, we don’t have a new substance, therefore this salt in solution doesn’t fit the microscopic definition of a chemical change; but we also don’t have the substance in its original form — a stack of alternating sodium and chlorine atoms. Does this mean the change is half chemical and half physical? Though it has aspects of a chemical change, scientists would still classify the dissolution of salt as a physical change.

The creation of a metal alloy: If we melt two types of metal together, we create an alloy metal that has different properties than either of its components (e.g., heat conductivity, electrical conductivity, density, etc.). This might lead us to think that we’ve witnessed a chemical change. In fact, a new particle is not created by melting two metals together. This indicates they did not undergo a chemical reaction. Brass, for example, is about 60% copper and 40% zinc, and is composed of individual copper and zinc atoms (i.e., there is no “smallest unit” that is still brass). There is no such thing as a brass molecule.


as far as making friends i don't give a hoot i just want some solid evidence to substantiate the claims of NS rail

Metals form metallic bonds. Lerner.org may not discuss it, but that is because it is a simplification intended for the layman with no knowledge of the field. If you want to learn chemistry, go to your local library and take out a copy of Brown, Bursten, & LeMay which is a common college text. A chemical reaction is one in which chemical bonds are formed or destroyed...the creation of an alloy is a chemical reaction. You have, in several posts, failed to convey any understanding of this concept...only resistance to it.

We have had many personal testimonies in this thread as to the reason why most of us prefer nickel silver. Eye witness testimony trumps theory in courts...especially when the theory is incomplete and not presented by an expert witness. A proper experiment would involve ovals of track and climate controls...it would help to reveal the roles played by some of the variables which affect the corrosion of the track. If different alloys are used in brass and nickel silver rail, then additional test tracks would be needed. This wouldn't be a fun or short experiment.

Increasing the Nickel raises the resistance to corrosion.
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Let's not forget that in large scale, brass track is quite common. The wider rails decrease the risk of corrosion interfering with the electrical pickup...and the greater weight probably makes it more effective at polishing the rail.

On a related note, I wonder if nickel silver first came to prominence with eating utensils for its appearance, its corrosion resistance, or both.

Jim, you are a fine model railroader whom is a pleasure to have on the forum. I don't think that you have made any enemies in this thread...just a friendly disagreement.

Michael