The most cost effective way: pickling passivation
The corrosion resistance of stainless steel is mainly because the surface is covered with a very thin (about 1nm) dense passivation film, which is isolated from the corrosion medium and is the basic barrier for stainless steel wire mesh protection. Stainless steel wire mesh passivation has dynamic characteristics and should not be regarded as a complete stop of corrosion, but as a barrier to diffusion, which greatly reduces the anode reaction speed. Usually in the presence of reducing agents (such as chloride ions) tend to damage the membrane, and in the presence of oxidants (such as air) can maintain or repair the membrane.
The stainless steel wire mesh workpiece will form an oxide film when placed in the air, but the protection of this film is not perfect. Usually, thorough cleaning, including alkaline cleaning and acid cleaning, and then passivation with oxidizing agent are required to ensure the integrity and stability of the passivation film. One of the purposes of pickling is to create favorable conditions for passivation treatment and ensure the formation of a
The corrosion resistance of stainless steel is mainly because the surface is covered with a very thin (about 1nm) dense passivation film, which is isolated from the corrosion medium and is the basic barrier for stainless steel wire mesh protection. Stainless steel wire mesh passivation has dynamic characteristics and should not be regarded as a complete stop of corrosion, but as a barrier to diffusion, which greatly reduces the anode reaction speed. Usually in the presence of reducing agents (such as chloride ions) tend to damage the membrane, and in the presence of oxidants (such as air) can maintain or repair the membrane.
The stainless steel wire mesh workpiece will form an oxide film when placed in the air, but the protection of this film is not perfect. Usually, thorough cleaning, including alkaline cleaning and acid cleaning, and then passivation with oxidizing agent are required to ensure the integrity and stability of the passivation film. One of the purposes of pickling is to create favorable conditions for passivation treatment and ensure the formation of a
high-quality passivation film. Because the surface of the stainless steel wire mesh surface is corroded by an average of 10μm thick by pickling, the chemical activity of the acid makes the dissolution rate of defective parts higher than other parts on the surface, so pickling can make the entire surface tend to be evenly balanced. The hidden dangers that could easily cause corrosion have been removed. But more importantly, through pickling passivation, iron and iron oxides are dissolved preferentially than chromium and chromium oxides, and th
e chromium-poor layer is removed, causing chromium to be enriched on the surface of stainless steel wire mesh. This chromium-rich passivation film The potential can reach +1.0V (SCE), which is close to the potential of precious metals, which improves the stability of corrosion resistance. Different passivation treatments will also affect the composition and structure of the film, thereby affecting the rust resistance. For example, through electrochemical modification treatment, the passivation film can have a multilayer structure, forming CrO3 or Cr2O3 on the barrier layer, or forming a glass state The oxide film of stainless steel wire mesh can exert maximum corrosion resistance.
Scholars at home and abroad have conducted a lot of research on the formation of stainless steel wire mesh passive film. Stainless steel wire mesh passivation is the dissolution of the surface layer and the adsorption of water molecules for some reason. Under the catalysis of the oxidant, oxides and hydroxides are formed, and the conversion reaction occurs with the Cr, Ni, and Mo elements that make up the stainless steel. The phase-forming film prevents the damage and corrosion of the film.
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