Pure titanium is a silver-white metal, which has many excellent properties. The density of titanium is 4.54g/cm3, which is 43% lighter than steel and slightly heavier than the prestigious light metal magnesium. The mechanical strength is similar to that of steel, two times greater than aluminum and five times greater than magnesium. Titanium is resistant to high temperatures, with a melting point of 1942K, which is nearly 1000K higher than gold and nearly 500K higher than steel.
Titanium is a metal with relatively active chemical properties. It can interact with non-metals such as O2, N2, H2, S and halogen when heated. However, at room temperature, a very thin and dense oxide protective film is prone to form on the surface of titanium, which can resist the action of strong acids and even aqua regia, showing strong corrosion resistance. Therefore, ordinary metals become riddled in acid, alkali, and salt solutions, while titanium is safe.
Liquid titanium can dissolve almost all metals, so it can form alloys with a variety of metals. Titanium steel made by adding titanium to steel is tough and elastic. Titanium and metal Al, Sb, Be, Cr, Fe, etc. form interstitial compounds or intermetallic compounds.
Aircraft made of titanium alloy can carry more than 100 passengers more than aircraft made of other metals with the same weight. The finished submarine can resist both seawater corrosion and deep pressure, and its diving depth is 80% higher than that of stainless steel submarines. At the same time, titanium is non-magnetic and will not be found by mines, and has a good anti-monitoring effect.
Titanium is "biophilic". In the human body, it can resist the corrosion of secretions and is non-toxic, and is suitable for any sterilization method. Therefore, it is widely used in the manufacture of medical equipment, artificial hip joints, knee joints, shoulder joints, flank joints, cranium, active heart valves, and bone fixation clips. When new muscle fiber rings wrap around these "titanium bones", these titanium bones begin to maintain the normal activities of the human body.
Titanium is widely distributed in the human body, and the content in a normal human body is no more than 15 mg per 70 kg of body weight. Its role is unclear. But titanium can stimulate phagocytes and enhance immunity, which has been proven.