Introduction
Titanium, named after the Titans of Greek mythology, represents strength and durability. This article explores the essence of titanium, its historical discovery, and how it measures up against other metals in terms of properties and applications.
What is Titanium?
Titanium is a chemical element with the symbol Ti and atomic number 22. It's a lustrous transition metal with a silver colour, low density, and high strength. Titanium is resistant to corrosion in sea water, aqua regia, and chlorine.
History of Titanium
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Discovery
Titanium was discovered in 1791 by William Gregor, an English clergyman and mineralogist, in the black sands of Cornwall. However, it was Martin Heinrich Klaproth, a German chemist, who named it after the Titans of Greek mythology in 1795.
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Commercialisation and the Kroll Process
The commercialisation of titanium was not realised until the 20th century due to the challenges associated with extracting it from its ores. In the 1940s, William J. Kroll developed the method known today as the Kroll Process, which still remains the main method for producing titanium metal.
The Kroll Process involves reducing titanium tetrachloride (TiCl4) with magnesium (Mg) in a large, sealed reactor at around 800°C. During the reaction, titanium is formed as a sponge-like mass that can then be purified by removing the magnesium chloride salt and any excess magnesium. The resulting titanium sponge is then melted in a vacuum arc furnace or through electron beam melting, to create ingots that can be further processed into various shapes and products.
The development of the Kroll Process made the extraction of titanium more feasible, paving the way for its use in advanced technologies and applications.
Properties of Titanium
Titanium is as strong as steel but 45% lighter. It's twice as strong as aluminium but only 60% heavier. Titanium's exceptional corrosion resistance and the highest strength-to-density ratio of any metallic element make it an ideal choice for a wide range of applications.
Comparison with Other Metals
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Titanium vs. Steel
- Strength: Both metals have high tensile strength, but titanium has the advantage of being much lighter.
- Corrosion Resistance: Titanium is highly resistant to corrosion by sea water and chlorine, while steel can rust and corrode.
- Cost: Steel is generally less expensive and more widely available than titanium.
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Titanium vs. Aluminium
- Weight: Titanium is heavier than aluminium but offers greater strength.
- Durability: Titanium is far more durable and can withstand higher temperatures without losing its strength.
- Cost: Aluminium is more cost-effective for lightweight applications.
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Titanium vs. Other Metals (Copper, Nickel, etc.)
- Conductivity: Metals like copper and nickel are more conductive than titanium, making them ideal for electrical applications.
- Malleability: Titanium is less malleable and harder to work with than many other metals.
- Specialised Use: Titanium is used where strength, lightweight, and longevity are paramount. Titanium fasteners cannot be replaced by those made of copper/brass/nickel etc because these metals do not have the requisite strength.
Applications
Due to its strength and resistance to corrosion, titanium is widely used in aircraft, armour plating, naval ships, spacecraft, and missiles. In more everyday applications, it is found in mobile phones, sporting goods, jewellery, and high-performance motorcycles and cars.
Conclusion
Titanium is a remarkable metal with a rich history and unique properties that set it apart from other elements in the periodic table. While its cost and difficulty in processing limit its use to some extent, the unparalleled strength-to-weight ratio and corrosion resistance of titanium make it indispensable in the automotive, advanced engineering, and technology sectors.
Paul Jordan, RSR Moto Ltd, 2023.