Naturally occurring platinum and platinum-rich alloys have been known
for a long time. The Spaniards named the metal "platina", or little
silver, when they first encountered it in Colombia. They regarded
platinum as an unwanted impurity in the silver they were mining.
Applications for these metals are many and include use in jewellery, catalytic converters,
fuel cells, and healthcare such as anti-cancer drugs and a variety of
surgical implants and prosthetics.
PGM's are also vital in their industrial role when used in fibreglass
production and petroleum refining, to name but a few examples and also in
technology such as mobile phones and computers.
The catalytic properties of the six platinum group metals are
outstanding. Platinum's wear and tarnish resistance characteristics are
well suited for making fine jewellery. Other distinctive
properties include resistance to chemical attack, excellent
high-temperature characteristics, and stable electrical properties.
All these properties have been exploited for industrial applications.
Platinum, platinum alloys, and iridium are used as crucible materials
for the growth of single crystals, especially oxides. The chemical
industry uses a significant amount of either platinum or a
platinum-rhodium alloy catalyst in the form of gauze to catalyze the
partial oxidation of ammonia to yield nitric oxide, which is the raw
material for fertilizers, explosives, and nitric acid.
In recent years, a number of PGMs have become important as catalysts in
synthetic organic chemistry. Ruthenium dioxide is used as coatings on
dimensionally stable titanium anodes used in the production of chlorine
and caustic. Platinum supported catalysts are used in the
refining of crude oil, reforming, and other processes used in the
production of high-octane gasoline and aromatic compounds for the
petrochemical industry. Since 1979, the automotive industry has emerged
as the principal consumer of PGMs. Palladium, platinum, and rhodium
have been used as oxidation catalyst in catalytic converters to treat
automobile exhaust emissions. A wide range of PGM alloy compositions is
used in low-voltage and low-energy contacts, thick- and thin-film
circuits, thermocouples and furnace components, and electrodes.
