Titanium is an element (chemical symbol Ti, atomic number 22) with a low density and strong durability. It is a strong, lustrous, corrosion-resistant transition metal with a silver color. The two most useful properties of the metal form are corrosion resistance and the highest strength-to-weight ratio of any metal. In its unalloyed condition, titanium is as strong as some steels, but 45% lighter. There are two allotropic forms and five naturally occurring isotopes of this element, Ti-46,Ti-47,Ti-48,Ti-49 andTi-50, and Ti-48 is most abundant among these five. Titanium is lighter than normal steel, but it is a lot more heavier than aluminum, however it is twice as strong as aluminum itself. Titanium will lose its strength when it is heated to 430 degree celcius, which is a pretty high temperature and that is why spaceship uses Titanium or its alloy. And since it is so hard that so drills have titanium coated on it. The reason why it is just "coated" is because titanium is so expensive. The other reason is titanium is so hard that it is difficult to change it shape when making the drill, so we just coat titanium on top instead. Because of titanium's corrosion-resistant (even in salty sea water) property, it is used to plate naval ships, missles, aircraft, spacecraft and armor. Titanium is also used in engines of the Air Bus A380. With titanium, aircrafts can become super light when durability is not a trade off. What is more important, titanium is non-tomix even in large doses in human body. So broken bones can be repaired with titanium. Besides all this, there's another common use -- pigment for painting. As we all know, most pigment we use are made from oxides of metals. And titanium's oxide form is used for making white pigments. The above does not include all the applications titaniums can be applied to, but now you know why titanium is so useful.