Chemical properties of titanium rod and titanium electrode _ oxidation from Mitchell's blog

Original Title: Chemical Properties of Titanium Rod and Titanium Electrode Chemical Properties of Titanium Rod and Titanium Electrode Titanium is a very corrosion-resistant metal. The thermodynamic data of titanium show that titanium is a very thermodynamically unstable metal. If titanium can be dissolved to form Ti2 +, its standard electrode potential is very negative (-1.63 V), and its surface is always covered with a passive oxide film. In this way, the stable potential of titanium is stably biased to a positive value, for example, the stable potential of titanium in seawater at 25.d egree. C. is about + 0.09 V. Standard electrode potentials corresponding to a series of titanium electrode reactions are available in chemistry handbooks and textbooks. It is worth pointing out that, in fact, these data are not directly measured, but often can only be calculated from thermodynamic data, and because of the different sources of data, it is not surprising that there are different data for several different electrode reactions that may be expressed at the same time. The electrode potential data of the electrode reaction of titanium show that the surface of titanium is very active and is usually covered with an oxide film formed naturally in air. Therefore,titanium seamless tube, the excellent corrosion resistance of titanium is due to the fact that there is always a layer of stable, adhesive and protective oxide film on the surface of titanium. In fact, the stability of this natural oxide film determines the corrosion resistance of titanium, including titanium rods,titanium round bar, titanium wires and titanium plates of titanium and titanium alloys. Of course, the corrosion resistance of various brands is different. We have talked about it in the previous content of the website, so I will not say more today. In theory, the P/B ratio of the protective oxide film must be greater than 1. If it is less than 1, the oxide film can not completely cover the metal surface, so it is impossible to play a protective role. If this ratio is too large, the compressive stress in the oxide film will increase accordingly, which will easily cause the rupture of the oxide film and will not play a protective role. The P/B ratio of titanium varies with the composition and structure of the oxide film, titanium filler rod ,Titanium welding pipe, ranging from 1 to 2.5. From this basic point of view, the oxide film of titanium can have better protection performance. When the titanium surface is exposed to the atmosphere or aqueous solution, a new oxide film will be automatically formed immediately. For example, the thickness of the oxide film in the atmosphere at room temperature is 1.2 ~ 1.6 nm, and it increases with time. After 70 days, it naturally increases to 5 nm, and after 545 days, it gradually increases to 8 ~ 9 nm. Artificially enhanced oxidation conditions (such as heating, using an oxidant or anodizing, etc.) Can accelerate the growth of the surface oxide film and obtain a relatively thick oxide film, thereby improving the corrosion resistance of titanium. Therefore, the corrosion resistance of titanium can be significantly improved by anodic oxidation and thermal oxidation. Now our customers have made many similar products with our titanium rods and wires, which shows that this is the way to work. The oxide film of titanium (including thermal oxide film or anodic oxide film) is usually not a single structure, and the composition and structure of its oxide vary with the formation conditions. In general, the interface between the oxide film and the environment may be TiO2, while the interface between the oxide film and the metal may be dominated by TiO. That is to say, the surface of the titanium rod we produced is TiO2, and the interface between the metal and the oxide film is TiO. This, of course, includes titanium plates, titanium alloy forgings are the same, and the surface of titanium alloy bars is more complex. However, whether pure titanium rod, titanium alloy rod or titanium alloy wire, there are transition layers of different valence States in the middle, even non-stoichiometric oxides, which indicates that the oxide film of titanium material has a multi-layer structure. As for the formation process of this oxide film,ti6al4v eli, it can not be simply understood as the direct reaction between titanium and oxygen (or oxygen in the air). Various mechanisms have been proposed by many researchers. In the former Soviet Union, workers believed that the hydride was formed first, and then a passive oxide film was formed on the hydride. Return to Sohu to see more Responsible Editor:. yunchtitanium.com