Titanium is a very active metal, its equilibrium potential is very low, and the thermodynamic corrosion tendency in the medium is high. But in fact, titanium is very stable in many media. This is because titanium has a high affinity for oxygen. In an oxygen-containing environment, a dense, strong adhesion and inert oxide film will be formed on the surface of Molybdenum Sputtering Target, thereby protecting the titanium matrix from Corroded; even if it is mechanically worn, it will quickly regenerate, which shows that titanium is a metal with a strong tendency to passivation. The outstanding performance of titanium is that it has extremely high corrosion resistance in fresh water and seawater. The corrosion resistance in seawater is better than aluminum alloy, stainless steel and nickel-based alloys. The dense oxide protective film with high chemical stability formed by titanium and oxygen ensures its high corrosion resistance in low and high temperature gases. At room temperature, titanium does not interact with chlorine, dilute sulfuric acid, dilute hydrochloric acid, nitric acid and chromic acid. It has high corrosion resistance in alkaline solutions and most organic acids and compounds, but it can be affected by hydrofluoric acid, phosphoric acid, Molten alkali erosion.
Seawater contains more than 10 kinds of ions such as Na+, K+, Mg²+, Cl-, etc., which is highly corrosive. The materials used in the ocean should generally be able to withstand the corrosion of the ocean atmosphere, seawater, tides (atmosphere and seawater alternately) and sea creatures, and also withstand seawater erosion and periodic impact of waves, so the material should have good corrosion resistance And better comprehensive mechanical properties. In addition, if the equipment is to float in water, low density and high strength are also very important. Experiments show that steel, stainless steel, copper, and aluminum are all non-corrosive materials in the marine environment, and coatings or other protective measures must be used when using them. Only titanium is a structure that is very corrosion-resistant and does not need coating protection. Material. Seamless Titanium Tube Grade 2 is also a material conducive to obtaining the most buoyant structure. The static pressure of sea water increases by 10.1kPa for every increase of 1m of water depth. In order to make the shell strong enough at a given water depth, the wall thickness of the shell must be increased.
Although titanium is a thermodynamically unstable metal, its standard potential is -1.63V (SHE), but due to the passivation effect of the oxide film, its corrosion potential is largely positively shifted. The self-corrosion potential of drinking in natural water at 25°C is about 0.1V (SCE). The titanium film has very good self-healing properties. When the film is damaged, it can be quickly repaired and replaced into a new protective film. Therefore, titanium can maintain its state in oxygen-containing liquids and non-ion-containing solutions.
In the marine environment, the drink is resistant to both uniform corrosion and local corrosion. Laboratory and engineering practices have shown that titanium has not been tested for significant corrosion after many years of exposure to seawater at different depths. Even if there are encroachments on the surface of the drink, crevice corrosion and pitting corrosion will not occur. The presence of sulfides in seawater does not affect the corrosiveness of the drink. Grade 9 Ti-3Al-2.5V Titanium Sheet does not have corrosion problems in the ocean atmosphere, flying test area and tidal range. Titanium can resist the erosion of high-speed seawater. The suspended friction particles in the seawater are very harmful to copper or aluminum alloy, but have little effect on titanium. Titanium has been recognized as one of the best anti-cavitation corrosion metal materials in seawater. Because titanium is not toxic to marine organisms, marine organisms attach to the surface of titanium more commonly, the titanium under the marine organisms does not undergo crevice corrosion and pitting corrosion, and the surface still maintains the integrity of the corrosion-resistant oxide film. Titanium hardly occurs in seawater pitting corrosion and crevice corrosion, so titanium is the most suitable material for seawater. Therefore, whether it is in still seawater or high-speed flowing seawater, whether it is clean seawater or polluted seawater, or even seawater containing a lot of mud and sand, titanium can maintain its state of transformation and exhibit excellent corrosion resistance.
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