3.11. Alloys http://www.ck12.org
FIGURE 3.19
Brass saxophone: Brass is an alloy of
copper and zinc. It is softer than bronze
and easier to shape. It’s also very shiny.
Notice the curved pieces in this shiny
brass saxophone. Brass is used for shap-
ing many other curved objects, such as
doorknobs and plumbing fixtures. Stain-
less steel sink: Stainless steel is a type of
steel that contains nickel and chromium in
addition to carbon and iron. It is shiny,
strong, and resistant to rusting. This
makes it useful for sinks, eating utensils,
and other objects that are exposed to wa-
ter. "Gold" bracelet: Pure gold is relatively
soft, so it is rarely used for jewelry. Most
"gold" jewelry is actually made of an alloy
of gold, copper and silver. Bronze statue:
Bronze was the first alloy ever made. The
earliest bronze dates back many thou-
sands of years. Bronze is a mixture of
copper and tin. Both copper and tin are
relatively soft metals, but mixed together
in bronze they are much harder. Bronze
has been used for statues, coins, and
other objects.Q:Sterling silver is an alloy that is used to make fine jewelry. What elements do you think sterling silver contains?
What properties might sterling silver have that make it more useful than pure silver?
A:Most sterling silver is about 93 percent silver and about 7 percent copper. Sterling silver is harder and stronger
than pure silver, while retaining the malleability and luster of pure silver.
Summary
- An alloy is a mixture of a metal with one or more other elements. An alloy generally has properties that make
it more useful than the pure metal. - Examples of alloys include steel, bronze, and brass.
Vocabulary
- alloy: Mixture of a metal with one or more other elements.
Explore More
Choose an alloy from the list at the following URL, and then do a Web quest to learn about its composition,
properties, and uses. Create a poster or brochure to share what you learn.