Titanium: The Color-changing Wonder Metal

Titanium is stable in the air at room temperature, and only when heated at high temperatures for a period of time does it produce "colorful" changes. This is mainly because, when titanium metal is heated in the air, it will be oxidized with oxygen, forming a layer of dense oxide film. This layer of oxide film can not only play a protective role on the surface of titanium metal, but also the fundamental source of titanium color changes. The reaction equation of titanium oxidation is Ti+O2==TiO2, and the reaction conditions are high temperature heating. In the heating temperature is low, the titanium surface of the oxide film is nearly transparent, people with the naked eye is relatively difficult to detect, but when the temperature rises, the oxide film in the pot will slowly thicken, and interference with the light, in the eyes of the people will also show a different color. So the thickness of the oxide film depth, determines the titanium surface will become what color.

According to relevant research shows that the same is heated in the air for half an hour, with 200 ℃ heated titanium surface for silver white, 300 ℃ for light yellow, 400 ℃ for golden yellow, 500 ℃ for blue, 600 ℃ for purple, 700 ℃ (to) -800 ℃ for gray-red, 900 ℃ for gray, the whole color change can be described as colorful. [1] natural gas fire temperature of 270-540 ° C, liquefied petroleum gas fire temperature of 365-460 ° C, city gas fire temperature of 270-605 ° C, are able to reach the temperature of titanium oxidation discoloration, if your family's titanium pots and pans can be discoloration, it means that you buy a Pure quality titanium pots.
Titanium oxide film can not only make titanium discoloration, but also greatly enhance the corrosion resistance of titanium. However, titanium oxide film is not the thicker, the better the corrosion resistance. When the heating temperature below 500 ℃, oxygen and titanium will generate a layer of dense oxide film of TiO2, the surface of titanium has a certain protective effect; heating temperature to 600 ℃ -700 ℃, titanium surface oxide film will become thicker; more than 700 ℃, although the thickness of the oxide film increased, but became loose, easy to rupture, the loss of the protective effect. So generally at room temperature, titanium has good corrosion resistance.