Corrosion Inhibitor Use of Titanium Alloy Plate

In reducing inorganic acids and some organic acids, the corrosion rate of titanium alloy plates is relatively fast because the passive oxide film cannot be maintained. Adding corrosion inhibitors is an effective measure to reduce corrosion. Candle retarders include precious metal ions, heavy metal ions, oxidative inorganic food, oxidative organic compounds, complex organic corrosion inhibitors, etc. The price of precious metal ions is very high, and it is rarely used as a corrosion inhibitor for reducing organic acids; to metal ions, copper ions and iron ions have very obvious corrosion inhibition structures, but they can only work after reaching a critical concentration; Oxidizing inorganic compounds include nitric acid, chlorine, potassium chlorate, potassium dichromate, potassium permanganate, hydrogen peroxide, etc.; oxidizing organic compounds include nitro or nitroso compounds, nitrogen compounds, etc.; complex organic retarders. Unlike oxidizing organic compounds, corrosives can inhibit corrosion at any concentration. There is no concept of critical concentration, but the effect is different.
Surface treatment is a very effective way to improve the corrosion resistance of titanium alloy sheets. The surface treatment methods include cathodic oxidation, thermal oxidation, nitridation and coating technology. The effects of anodizing, thermal oxidation and coating on the crevice corrosion time of titanium alloy plates, the data show that the effect of coating on improving the corrosion resistance of titanium alloy plates is the most obvious, even better than the corrosion resistance of Ti-0.15Pd .
The anodic oxidation of titanium alloy plate is usually carried out in 5%-10% (NH4)2sO solution and 25V DC voltage is applied for anodic treatment, and the thickness of the anodic oxide film can reach 300-500nm. Anodizing treatment can effectively remove iron contamination on the surface, effectively prolong the passivation time of titanium alloy plates, and prevent hydrogen absorption caused by positive iron contamination. Therefore, foreign specifications require that all titanium equipment must be anodized. In order to improve the effect of anodizing, sodium platinate is used instead of ammonium sulfate in the anodizing solution, so that the effect of corrosion resistance is better.
The thermal oxidation of the titanium alloy plate in the air can form a rutile-type thermal oxidation strand with a thicker and higher crystallinity than the anodized film, and its corrosion resistance is better than that of the anodized film. The thermal oxidation strand of the titanium alloy plate is formed at a temperature of 600-700 ℃ and a time between 10-30 minutes. If the temperature is too high or the time is too long, the effect is not good.
In the coating layer of titanium alloy plate, the effect of removing the layer is the best, and the coating containing palladium is usually an oxide coating or a lead alloy coating. The typical preparation method of palladium oxide coating PdO-T102 is to apply PdCL4 and TiCL3 solutions to the surface of the titanium alloy plate, and heat it at 500-600 ° C for 10-50 min, which can be repeated several times to make the coating thickness 1g /m2 or more. The riveting alloying Xu layer is firstly deposited by electroplating or vacuum deposition of a thin layer, and the surface alloying treatment technology such as laser remelting surface or ion implantation is carried out, and its adhesion and corrosion resistance are better than that of the oxide coating.
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