Titanium

Titanium is used in dental implants and many prosthetics because it combines mechanical resistance with good compatibility with the body. Its surface forms a very thin oxide layer that limits corrosion and contributes to the material remaining stable in the body. In dental implants, osseointegration can occur, a process by which bone forms a tight union with the implant surface. The result also depends on design, surface treatment and patient conditions.

Titanium offers an attractive combination of mechanical resistance, relatively low density and good corrosion behaviour. Some of its alloys maintain useful properties in demanding conditions, so they are used in engine components, structures and aerospace systems. Although usually heavier than aluminium, it can support loads and temperatures that make its use advantageous in certain parts. Its manufacture and machining are costly, so it is selected where its performance justifies that investment.

Titanium can take on different colours through treatments that modify its oxide layer on the surface. In certain processes, the thickness of this film produces optical interferences making reflected light have different tones, such as blue, violet, gold or green. The colour is not necessarily due to an added pigment, but to the interaction of light with that surface layer. This method is used in jewellery and decorative objects, although the hue depends on the treatment and lighting conditions.

Pure titanium stands out for its corrosion resistance and compatibility with the body, while alloys incorporate other elements to modify properties such as strength, hardness or behaviour at different temperatures. For example, some alloys with aluminium and vanadium are used in aerospace and medical components because they offer high mechanical resistance. The choice between pure titanium and an alloy depends on the application: there is no single composition that is the best for all needs.

Titanium dioxide is a white compound with great capacity to scatter visible light, so it is used as a pigment in paints, coatings and other products. In sunscreens, certain formulations of this compound help attenuate ultraviolet radiation. Its properties depend on particle size, surface coating and how it is incorporated into the product. Thus, titanium dioxide has different applications depending on its formulation and should not be confused with pure metal.

When titanium is exposed to air or an oxygen-containing medium, its surface spontaneously forms a very thin and adherent layer of titanium oxide. This layer acts as a barrier and makes it difficult for the material to continue reacting with the environment. If the surface suffers damage, the layer can reform under suitable conditions, a behaviour known as passivation. This protection explains its usefulness in chemical equipment, marine applications and implants, although the specific resistance depends on the medium and usage conditions.

Although its properties are valuable, titanium can be difficult to machine because it conducts heat worse than many other metals and maintains considerable resistance during cutting. This concentrates heat in the tool and can accelerate its wear. In addition, titanium reacts with some gases at high temperatures, so certain processes require a controlled atmosphere. Selection of tools, speeds, cooling and manufacturing techniques is essential to obtain quality parts without unnecessarily increasing costs.