1. Titanium net dense oxide film corrosion resistance
Titanium mesh is made of titanium metal, if you want to explain the corrosion resistance of titanium mesh to study the corrosion resistance of titanium and the principle. Titanium is a metal with a strong passivation tendency. However, the thermodynamic data of titanium show that titanium belongs to thermodynamically and unstable metals. Titanium can dissolve to produce Ti2 + its standard electrode potential is very negative (-1.63V), the surface is always covered with a layer of pure titanium oxide film. This makes the stable potential of titanium stable positive bias.
For example, the titanium wire has a stable potential of about +0.09 V in seawater at 25 ° C. Titanium net electrode when the reaction potential shows that the surface is very lively, usually covered with a layer of oxide film, this film is naturally produced in the air, it is this layer of stability, strong adhesion, strong protective oxidation Film, determines the excellent corrosion resistance of titanium mesh.
Therefore, titanium mesh produced from pure titanium raw materials can produce a stable oxidizing protective film in air and oxidizing or neutral aqueous solution quickly, even if the oxide film is damaged for some reason, it can be recovered quickly. For example, the offspring of the oxide film at room temperature is about 1.2-1.6 nm and thickens over time. 70 days after the natural kind of 5nm, 545 days later gradually increased to 8-9nm. Artificially enhanced oxidation conditions (such as heating, the use of oxidants or anodizing, etc.) can accelerate the growth of surface oxide film and get a thick oxide film, will significantly improve the corrosion resistance of titanium.
The oxide film (including the thermal oxide film or the anodic oxide film) of the titanium mesh is usually not a single structure, and the composition and structure of the oxide varies depending on the generation conditions. Under normal circumstances, the interface between the oxide film and the environment may be TiO2, but in the oxide film and metal interface may be mainly TiO. There may be different valence of the transition layer, or even non-chemical equivalent of oxide, which means that titanium oxide film from the multi-layer structure. Therefore, titanium mesh in the oxidizing, neutral medium has excellent corrosion resistance.
Titanium network reacts with oxygen and nitrogen, it is easy to form a layer of titanium mesh on the surface of a very high stability, dense, and the matrix with a solid oxide film or nitride film, isolated corrosive media to further corrosion of titanium mesh matrix, And aluminum is similar to the surface of the titanium oxide corrosion resistance is very good, very resistant to chloride ions corrosion, it can be said that the basic oxidation of the titanium oxide oxide film is not corrosion, so very resistant to corrosion in the sea. Therefore, in the sea, titanium corrosion resistance than aluminum, stainless steel, nickel-based alloys are good.
2. Titanium mesh surface coating corrosion resistance
Titanium mesh is a pure titanium wire square hole weaving production of the filter, pure titanium wire in the cold drawing will be coated with graphite coating, one can guarantee pure titanium wire diameter uniformity, the difference is small, the second is Lubricating mold to improve production efficiency, and third, drawing graphite and pure titanium wire substrate is very close, the coating thickness of about 20 microns, when the drawing with a graphite coating titanium mesh soaked in seawater, the coating can Effective separation of titanium mesh and sea water contact to prevent seawater corrosion titanium mesh, it can be said that the titanium coating to give titanium mesh in the sea better corrosion resistance and improve its service life.
Summary: The oxide film provides a chemical layer of corrosion resistance for the titanium mesh, and the brushed graphite coating provides a physical layer of corrosion resistance for the titanium mesh.