Titaniums

Titaniums refers to titanium and its alloyed forms. Titanium is a chemical element with the symbol Ti and atomic number 22. It has a high strength-to-weight ratio, excellent corrosion resistance, a relatively low density, and a high melting point. It is also biocompatible, which supports its wide use in implants and health-related devices.

Natural occurrence and production: Titanium is abundant in the Earth's crust, chiefly in minerals such as ilmenite and rutile. Industrial production typically converts ore to titanium tetrachloride (TiCl4) and then reduces it to metal. The dominant method is the Kroll process, in which TiCl4 is reduced with magnesium in molten salt. An older or alternative method is the Pidgeon process, which reduces TiO2 with silicon and carbon. After purification, titanium is alloyed and formed into usable products.

Properties: Titanium metal has a density of about 4.5 g/cm3, a modulus near 110 GPa, and a melting point around 1,668°C. It resists corrosion from seawater and many acids and bases, and maintains strength at elevated temperatures. While relatively easy to fabricate into complex shapes, it is more challenging to machine than many steels, and surface finishing is important to optimize wear and fatigue performance. Its biocompatibility makes it favorable for medical implants.

Alloys and grades: The most widely used alloy is Ti-6Al-4V (Ti-6Al-4V). Commercially pure grades 1–4 vary in strength and ductility. Specialty alloys, such as Ti-6Al-2Sn-4Zr-2Mo or Ti-6Al-4V ELI, tailor properties for implants or high-temperature service. Surface coatings (e.g., TiN) can enhance hardness and wear resistance.

Applications and challenges: Titaniums and their alloys are employed in aerospace components, aircraft engines, spacecraft, chemical processing equipment, and medical implants. They are valued for strength, lightness, and corrosion resistance, but the material’s cost and machining difficulty are limiting factors. Recycling and sustainable production are increasingly emphasized in its supply chain.