Pure titanium is a silver-white metal that has many excellent features. Titanium has a density of 4.54 g/cm3, which is 43% lighter than steel and slightly heavier than the long-established light metal magnesium. The mechanical strength is similar to steel, twice as large as aluminum and five times larger than magnesium. Titanium is resistant to high temperatures and has a melting point of 1942K, which is nearly 1000K higher than gold and nearly 500K higher than steel. Titanium belongs to metals that are more chemically active. Non-metallic effect such as O2, N2, H2, S and halogen when heated. However, at normal temperature, the titanium surface is prone to form a very thin and fine oxide protective film, which can resist the strong acid and even the effect, showing strong corrosion resistance.