Iridium: A Rare and Corrosion-Resistant Element
Iridium, a rare and corrosion-resistant element, is primarily found in platinum ores and extracted during the mining of other metals. Its price has recently surged due to high demand from the tech industry. Iridium is one of the rarest elements on Earth and is associated with the meteor that caused the extinction of dinosaurs.
Iridium is a transition metal (Ir) with an atomic weight of 192.217 and a density of 22.56 g/cm³, making it the second-densest element. Due to its high cost, iridium is mainly used in applications requiring small amounts of the element.
Corrosion Resistance and Rarity
Iridium is Earth's most corrosion-resistant metal, with an exceptionally high melting point that makes it challenging to shape or work. Additionally, it ranks among the rarest elements in the Earth's crust. Scientists associate a colossal asteroid impact around 65 million years ago with the presence of an iridium-rich clay layer, marking the Cretaceous-Paleogene boundary, also known as the K-Pg boundary.
A Brief History
Discovered in platinum ore residues in 1803, iridium was identified by English chemist Smithson Tennant. He named it after Iris, the Greek rainbow personification, due to its colorful salts. Iridium's high melting point posed challenges until its isolation in 1842. It's among Earth's rarest elements, with gold being 40 times more common. In 1961, German chemist Rudolf Ludwig Mössbauer won a Nobel Prize in physics for his research on the Mössbauer effect, using iridium to study gamma radiation resonance absorption.
Applications and Demand
Iridium's high melting point finds applications in various industries. It's used in spark plugs for aviation, crucibles for extreme temperature processes like sapphire crystal production, and in combination with osmium for making fountain pen nibs, pivot bearings, and specialized equipment.
In recent years, iridium's role in manufacturing LED screens and backlit displays for devices like iPads and iPhones has driven demand, causing its price to soar. After the release of the first iPad in 2010, iridium prices surged to over $1,000 per troy ounce, and by March 2022, they reached nearly $4,900 per troy ounce. This makes iridium more valuable than gold, silver, or platinum.
Comparison to Palladium
Iridium and palladium, both noble metals akin to platinum, share key industrial applications. They possess high melting points, exceptional electrical conductivity, and outstanding corrosion resistance, rendering them valuable in electronics and various industries. Palladium finds common use in catalytic converters, reacting with exhaust hydrocarbons. Conversely, iridium's heat tolerance makes it a preferred choice in electronics.
Iridium Spark Plugs
Iridium, known for its high electrical conductivity and resistance to corrosion at high temperatures, is commonly employed in spark plugs, the ignition devices for combustion engines. It outperforms platinum, another precious metal used in premium spark plugs, being six times harder and eight times stronger. Copper spark plugs have a lifespan of around 20,000 miles, while platinum extends it to 100,000 miles. Iridium spark plugs can go even further, lasting up to 25% longer, albeit at a higher price range of eight to fifteen dollars per plug.
Iridium is a rare and corrosion-resistant element that has diverse applications in various industries. Its high melting point, exceptional electrical conductivity, and resistance to corrosion make it valuable in electronics, spark plugs, and specialized equipment. The demand for iridium, particularly in the tech industry, has driven its price to surpass that of gold, silver, and platinum. As one of the rarest elements on Earth, iridium continues to be a fascinating and sought-after metal with unique properties.