Zinc Vs. Brass

The Facts

• Brass is an alloy, a composite of two elements: two thirds copper, one third zinc. Its properties come from the copper, the zinc and the interactions between the two elements. Zinc is purely an element, meaning its properties come from the properties of zinc alone. Brass is more durable than zinc, but also easier to shape; making it perfect for making utensils and parts for furniture, such as handles.

Boiling Point

• Zinc on its own has a melting point of 787 degrees Fahrenheit (419 degrees Celsius). Brass, on the other hand, has a far higher melting point of 1,652 degrees Fahrenheit (900 degrees Celsius). This is due to the strong metallic bonds between the copper and zinc atoms that make up the brass molecules. The stronger the bonds in a molecule, the higher the temperature must be before they will break and allow the metal to become liquid.

Corrosion

• Brass will corrode on its own but can be mixed with iron or aluminum to become resistant to corrosion. Zinc, on the other hand, is highly corrosive; with the surface of the zinc reacting with oxygen to form an oxide layer similar to that of aluminum. Like with aluminum, this oxide layer protects the zinc beneath it from harm, meaning the zinc can last for centuries without further damage due to corrosion.

Cracking

• Brass is more malleable than zinc, meaning it can be bent and shaped more easily. As a result, brass is less prone to stress cracking than zinc on its own; which can crack when exposed to pressure or when bent. However, in the presence of ammonia, brass becomes more susceptible to cracking due to interactions between the ammonia and the metal changing the bonds inside the brass.