From IT equipment to space engineering… What kind of material is titanium

Titanium is a material that is often used around automobile mufflers and Apple Watches. Originally, it was used as a component material for aircraft and rockets, but now it is also used for seawater desalination systems, offshore piers, and heat exchangers. In the field of architecture, it is also used for roof and wall materials, railings, and monuments. Not only that, it is also used in medical devices, such as implants and artificial roots.

Titanium is also used in home appliances. There were also products such as automobile and motorcycle mufflers, cameras and golf clubs, eyeglass frames, mountaineering and outdoor equipment, and in the past, titanium powerbooks. Recently, it is also attracting attention as a watch material.

Then, what kind of properties does the metal of titanium itself have? Titanium’s characteristics can be said to be light and strong. Titanium is about 40% lighter than stainless steel, and has a high strength and nasal cavity compared to stainless steel. The mass ratio of water of the same volume as the object is 7.9 for stainless steel, but 4.51 for titanium. In other words, when making the same strength, titanium is lighter than stainless steel.

Aluminum is also made of the same material, but titanium is heavier in terms of weight. However, if you look at the nasal cavity, titanium is higher, so if you make things with the same strength, titanium is lighter than aluminum. Also, one of the characteristics of titanium is that it is more difficult to rust than stainless steel and aluminum. It doesn’t mean it’s not rusted at all, but it’s not easy to corrode. Thanks to this feature, it was also used in space and aviation related fields.

Another hidden feature of titanium is that it is not allergic to metals. This is due to the passive oxide film formed on the surface of titanium. Therefore, this is why it is attracting attention as a watch material that always touches the skin.

Of course, there are also drawbacks. It means that it doesn’t shine at all. There is no shiny gloss like stainless steel processing. It takes quite a while to polish. It also has the disadvantage of being softer than stainless steel and aluminum. The specific strength is high, but if you simply compare titanium, stainless steel, and aluminum, titanium is softer.

Of course, soft titanium means 100% titanium. Usually, a titanium alloy in which aluminum or the like is added to titanium is used to achieve hardness. The weakness of this softness is that it is weak against abrasion, but pure titanium is easy to be damaged due to its low abrasion resistance. Titanium is characterized by being light, strong and not rusted, but difficult to polish and weak against abrasions.

When it comes to titanium, it’s easy to think that it usually has a luxurious image. In fact, the price is higher than that of stainless steel and aluminum. Is titanium more expensive because it is a precious metal? In fact, however, titanium is the fifth-largest metal on Earth. The reason for the high price is that it is difficult to process. Titanium is susceptible to oxidation. In order to be able to use titanium, the extracted titanium oxide or minerals containing the same must be synthesized, crushed, or melted into a metal state that can be processed. For titanium oxide, all of these processes must be carried out in a vacuum or in a tank filled with an inert gas such as argon or helium. It’s a lot of work on tablets. For this reason, the price is about 10 times higher than that of stainless steel. It is said that titanium material itself is not of high scarcity value, but rather expensive, which requires a lot of cumbersome process until it can be used.

To change the color of titanium, anodization method is used to change the color of titanium through electricity. Titanium itself is said to be capable of developing more than 100 different colors using this method. The anodic oxidation method is a method to develop color by controlling light reflection by changing the thickness of the oxide film on the surface of titanium. In theory, it is said that any color included in visible light can be reproduced.

However, black cannot be discharged this way. Because white is the result of mixing various colors, it is impossible to use anodic oxidation with a specific color. In addition, since black is simply a problem of brightness that is dark, color development using visible light components, and due to the nature of titanium, cannot produce a color called black.

But in reality, among the products on the market, there is also black titanium. How did it become black? In fact, it is coated with black titanium carbon and the like. This carbon coating not only darkens the color, but also contributes to the hardening of the titanium surface. Easily visible white or black color requires considerable skill in titanium.