Titanium powder is a silver-gray irregular powder with a large inspiratory
capacity and is flammable under high temperature or electric spark conditions.
Among the metal elements, the specific strength of titanium is high. It is a high strength but low quality metal with very good ductility (especially in an oxygen free environment). The surface of titanium is a silvery white metallic luster. Its melting point is quite high (more than 1,649 degrees Celsius), so it is a good refractory metal material. It is paramagnetic and has very low conductivity and thermal conductivity.
Commercial grade titanium (purity of 99.2%) has an ultimate tensile strength of approximately 434 MPa, which is comparable to low grade steel alloys but 45% lighter than steel alloys. Titanium has a 60% higher density than aluminum, but its strength is twice that of the usual 6061-T6 aluminum alloy. Titanium can be used in a variety of applications. Some titanium alloys (eg, βC) have a tensile strength of 1,400 MPa. However, when titanium is heated above 430 degrees Celsius, the strength is reduced.
Among the characteristics of titanium, the most famous is its excellent corrosion resistance - its corrosion resistance is almost as good as platinum, titanium is not corroded by dilute sulfuric acid, dilute hydrochloric acid, chlorine, chlorine solution and most organic acids. But it can still be dissolved by concentrated acid. Although the potential-pH diagram below indicates that titanium is thermodynamically a highly reactive metal, its reaction with water and air is very slow.
When exposed to high temperature air, titanium forms a protective film of oxidized oxide to prevent oxidation. At the time of initial formation, the protective layer was only one to two nanometers thick, but it continued to thicken slowly; it could reach 25 nanometers thick in four years. However, when titanium is placed in high temperature air, it is easy to react with oxygen.
Titanium is also one of the few elements that will burn in pure nitrogen. When it reaches 800 degrees Celsius, it will burn and form a titanium nitride, which will cause embrittlement.