Transition Metals, Corrosion & Alloys Flashcards

Flashcards about Transition Metals, Corrosion & Alloys

Metals

Elements that readily lose electrons to form positive ions with delocalized electrons surrounding them.

Transition Metals

Relatively hard, strong, shiny, ductile, malleable materials that conduct heat and electricity well. High melting points (except mercury). High densities and shiny when polished.

Gold

Shiny and malleable, great electrical conductor, corrosion resistant, used in jewellery and some electronic components.

Copper

Malleable and corrosion resistant, good electrical conductor, used for water pipes and electrical wiring.

Catalyst

Speeds up the rate of a reaction without being changed or used up.

Oxidation of Metals

When a metal reacts with oxygen in the air to form metal oxides, leading to a thin layer called tarnish that can prevent further oxidation.

Corrosion

When a metal continues to oxidize, causing it to weaken over time.

Rusting

The corrosion of iron or steel when it reacts with oxygen and water, forming hydrated iron(III) oxide.

Hydrated iron(III) oxide

Orange-brown substance seen on rusty objects.

Sacrificial Protection

A method of rust prevention that uses a more reactive metal such as magnesium or zinc to oxidize instead of the protected metal like iron or steel.

Corrosion of metals

Caused by redox reactions where the metal loses electrons (is oxidized) and oxygen gains electrons.

Alloy

A mixture of a metal element with one or more other elements, usually metals, resulting in a stronger material due to the distorted arrangement of atoms.

Steels

Steels are iron alloys with small amounts of carbon added. Alloy steels also contain other metals.

Low carbon steel

Easily shaped, containing 0.1 – 0.3% carbon.

High carbon steel

Very strong, inflexible, brittle, containing 0.22 – 2.5% carbon.

Stainless steel

Corrosion-resistant, strong, containing chromium and sometimes nickel.

Bronze

Copper + Tin, harder than copper, used to make medals, decorative ornaments and statues.

Brass

Copper + Zinc, more malleable than bronze, used in water taps and door fittings.

Gold Alloys

Metals such as zinc, copper, and silver are used to strengthen it.

Aluminium Alloys

Alloyed with small amounts of other metals to increase its strength due to low density, which is important in aircraft manufacture.

Magnalium

Aluminium + Magnesium, stronger, lighter and corrodes less easily than pure aluminium when made with 5% magnesium, used to make parts for cars and aeroplanes.