Titanium: Properties, Characteristics, and Medical Uses
Introduction
Titanium is a chemical element (Ti), located in the group of transition metals. This metal is very light, 50% lighter than steel (a metal it competes against in technical applications). Titanium has a high resistance to corrosion and high mechanical strength, but is much more expensive than steel, which limits its industrial use.
It is a very abundant metal in nature. It is estimated to be the ninth most abundant, but not in a pure state. It is found in the form of oxides in the slag of certain iron ores and in the ashes of plants and animals. All igneous rocks and sediments, as well as many minerals, especially those containing iron, and all plants and animals, contain titanium.
Characteristics of Titanium
We will differentiate between chemical-physical characteristics to make it easier to enumerate.
Chemical Characteristics
- It has a high resistance to corrosion. This is due to the passivation phenomenon it undergoes (forms an overlying oxide).
- It is resistant to diluted sulfuric acid (H2SO4) and hydrochloric acid (HCl) solutions, as well as other organic acids. However, it can dissolve in hot acids, and it also dissolves in hydrofluoric acid (HF).
- Dimorphic, at room temperature it has a hexagonal close-packed structure called the alpha phase. Above 882ºC it has a body-centered cubic structure, known as beta.
Physical Characteristics
- It is a light metal, with a specific weight of 4.5 g/cm3.
- Its melting point is 1675ºC.
- Highly resistant to corrosion and oxidation.
- A poor conductor of heat and electricity.
- It is paramagnetic (it is not magnetized because of its electronic structure).
- It is silver.
- It is a transition metal whose atomic weight is 47.867 u.
- Forms alloys with other elements to improve mechanical performance.
Mechanical Properties
- Ductile, allows the fabrication of thin wire.
- Malleable, allows the production of very thin sheets.
- Hard, has a level 6 on the Mohs scale.
- Tough.
- Highly resistant to traction.
- It can have a high storage capacity of its form.
Uses of Titanium
Applications in Medicine: Surgical Titanium
Titanium is a biocompatible metal, meaning the body’s tissues tolerate its presence without triggering an immune system rejection reaction. This property of biocompatibility, combined with its mechanical qualities of strength, lightness, and durability, have made possible a large number of useful applications in the field of medicine, such as:
- Hip and knee prostheses
- Bone screws
- Plates and anti-trauma components
- Dental implants
- Components for the manufacture of heart valves and pacemakers
- Surgical instruments (scalpels, scissors, etc.)
Titanium’s inert oxide cover is insoluble in contact with the tissues, preventing the release of ions that could react with organic molecules. In living tissue, it provides a surface on which bone can grow. When it does, it sticks to the metal, forming an anchor. This process is called osseointegration. This reaction usually occurs only in biocompatible materials.