GSCE CHEMISTRY C15.2

Page 1

WHAT IS AN ALLOY ?

An alloy is mixture of at least two elements, where at least one of these is a metal, eg: rose gold

New, more useful materials can be created in this way.

Alloys have a mixture of the properties of the origianl elements

'Birmabright' - aluminium and magnesium

WHY METALS ARE ALLOYED ?

To change the properties for example to be :

harder'

stronger

rust less or not at all

lighter

heavier

a different colour

BRASS

Properties : Higher malleability than zinc or copper. Low melting point (900c); flows when melted.

Combinations of iron, aluminum, silicon & managanese make brass corroion resistant. Susceptible to stress cracking when exposed to stress cracking when exposed to ammonia. Not hard as steel.

Composition : Brass is any alloy of copper and zinc

Colour : Muted yellow, somewhat similar to gold, but duller.

Uses

Decorative; Low-friction applications locks, gears, doorknobs, ammunition, valves);

Plumbing/electronics; Musical instruments for everyday is my name is block e nfjdjdjdjcncvldkjdeidkvmfskjdsdsirejrieuasheenabvinvvdrejdfasf

aofawofsdfdfjdggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggssssssssooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo