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CN-122013179-A - Stable reagent for weathering steel rust layer in complex environment and accelerated stabilization treatment method

CN122013179ACN 122013179 ACN122013179 ACN 122013179ACN-122013179-A

Abstract

The invention discloses a reagent for stabilizing a weathering steel rust layer in a complex environment and a method for accelerating stabilization treatment, and the reagent system comprises a rust layer stabilizer and a rust agent, wherein the rust layer stabilizer takes water as a solvent and comprises chromium sulfate, sodium molybdate and sodium phosphate, and the rust agent is weakly acidic high-concentration sodium chloride and sodium sulfate and is used for simulating a complex corrosion environment of ocean-industrial atmosphere. The invention controls the deposition amount and deposition time of corrosive liquid spray through the steps of surface pretreatment, rust agent spray deposition, and cyclic spraying and drying of rust layer stabilizer, and is matched with the cyclic treatment of the rust layer stabilizer to rapidly construct a compact and stable protective rust layer mainly comprising alpha-FeOOH on the surface of steel. The method can avoid the risk of ageing and peeling of the organic coating, obviously shortens the formation period of the stable rust layer on the surface of the weathering steel, generates compact and uniform rust layer, and is suitable for protecting the weathering steel structure in the marine-industrial complex atmospheric environment.

Inventors

  • ZHANG SHENGHUA
  • ZHOU YI
  • Mo Xinwei
  • WANG JIA
  • LIU QIXIANG
  • WANG YANLI

Assignees

  • 广西大学

Dates

Publication Date
20260512
Application Date
20260126

Claims (10)

  1. 1. The weathering steel rust layer stabilizing reagent is characterized by comprising a rust layer stabilizer and a rust agent, wherein the rust layer stabilizer comprises one or more of chromium sulfate, sodium molybdate and sodium phosphate, and the rust agent comprises one or two of sodium chloride and sodium sulfate.
  2. 2. The agent for stabilizing a weathering steel rust layer in a complex environment according to claim 1, wherein the chromium sulfate concentration in the rust layer stabilizer is 0.3 to 2g/L, calculated as anhydrous chromium sulfate, and the hydrate is contained in an equivalent concentration converted into an anhydrous substance.
  3. 3. The reagent for stabilizing a weathering steel rust layer in a complex environment according to claim 1, wherein the concentration of sodium molybdate in the rust layer stabilizer is 0.8-4 g/L, calculated as anhydrous sodium molybdate, and the sodium molybdate is contained in an equivalent concentration of hydrate converted into anhydrous.
  4. 4. The reagent for stabilizing a weathering steel rust layer in a complex environment according to claim 1, wherein the concentration of sodium phosphate in the rust layer stabilizer is 0.6 to 3g/L, calculated as anhydrous sodium phosphate, and the sodium phosphate contains an equivalent concentration of hydrate converted into anhydrous.
  5. 5. The reagent for stabilizing a weathering steel rust layer in a complex environment according to claim 1, wherein the concentration of sodium chloride in the rust agent is 32-40 g/L.
  6. 6. The reagent for stabilizing a weathering steel rust layer in a complex environment according to claim 1, wherein the concentration of sodium sulfate in the rust agent is 10-18 g/L.
  7. 7. The reagent for stabilizing a weathering steel rust layer in a complex environment according to claim 1, wherein the acidic pH value of the rust agent is 4-5, and the reagent for adjusting the pH value is nitric acid.
  8. 8. The agent for stabilizing a weathering steel rust in complex environments according to claim 1, wherein the solvents of the rust layer stabilizer and the rust agent are both water.
  9. 9. An accelerated stabilization treatment method based on the agent for stabilizing a weathering steel rust layer in a complex environment according to any one of claims 1 to 8, characterized by comprising the steps of: (1) Pretreating the surface of weathering steel, polishing by sand paper to remove a surface oxide layer, cleaning greasy dirt and residues by using anhydrous kerosene and absolute ethyl alcohol in sequence, and drying after cleaning; (2) Obliquely placing the pretreated weathering steel at an inclination angle of 30-45 ℃, spraying a rust agent on the surface of the weathering steel at an ambient temperature of 25-40 ℃, continuously spraying for 8-16 hours at a spraying deposition amount of 180-300 ml.m -2 ·h -1 , and then naturally drying; (3) Spraying rust layer stabilizer on the surface treated in the step (2), wherein the spraying amount is 0.2-0.3 L.m -2 , the environment temperature is 25-40 ℃, naturally drying after spraying, and standing for 5-15 hours in a dry state; (4) And (3) repeating the rust agent spraying treatment of the step (2) and the rust layer stabilizer spraying treatment of the step (3), and forming a compact and stable protective rust layer on the surface of the weathering steel through multiple cycles.
  10. 10. The accelerated stabilization method for a weathering steel rust layer stabilizer in a complex environment of claim 9, wherein in step (4), the number of cyclic operations is 8 to 12.

Description

Stable reagent for weathering steel rust layer in complex environment and accelerated stabilization treatment method Technical Field The invention relates to the technical field of corrosion and protection of metals, in particular to a weathering steel rust layer stabilizing reagent and an accelerated stabilization treatment method for complex environments. Background The weather-resistant steel, i.e. the atmospheric corrosion-resistant steel, is a low-alloy high-strength structural steel which is prepared by adding a small amount of copper, chromium, nickel, molybdenum and other alloy elements on the basis of common carbon steel. The core mechanism is that a layer of compact, stable and strong-adhesion inner rust layer is formed through controllable corrosion reaction with oxygen and moisture in natural environment, the main component is alpha-FeOOH (goethite), and the rust layer can effectively prevent external corrosion medium (such as O 2、H2O、Cl-、SO2 and the like) from diffusing to a matrix, so that further corrosion of the matrix is obviously slowed down, and a long-acting protection mechanism of rust prevention is realized. Compared with the traditional coating corrosion prevention mode, the weather-resistant steel has the advantages of no maintenance, long service life, environmental protection, attractive appearance and the like, and is widely applied to the fields of bridges, towers, building curtain walls, railway vehicles and the like. The application of weathering steel in practical engineering can be roughly divided into three types, namely surface coating treatment, bare use and rust layer stabilization treatment. The coating treatment has the advantages of excellent protective performance, high cost, complex construction, containing organic volatile matters and needing regular maintenance, natural film forming is dependent on bare use, the film forming period usually needs 2-5 years, problems of rust flowing, pollution to components and surrounding environment are easy to occur in the film forming period, particularly in areas with frequent rainfall or high humidity are more serious, and the rust layer stabilization treatment aims to accelerate the formation process of a protective rust layer, shorten the 'dangerous period', improve early corrosion resistance and reduce environmental influence through a manual intervention means, so that the method becomes a current research hot spot. The corrosion process of weathering steel in the atmosphere is a complex electrochemical and chemical reaction coupling process, the formation of rust layer of which goes through multiple stages. In the initial stage, the surface of steel reacts with oxygen and moisture in the air to generate unstable low-valence iron oxides and hydroxides, mainly comprising gamma-FeOOH, fe 3O4 and a small amount of Fe 2O3. With prolonged exposure, these initial corrosion products undergo further oxidation, hydration and phase change reactions in the presence of water, oxygen and electrolyte. The gamma-FeOOH is metastable hydroxyl ferric oxide, has higher specific surface area and reactivity, has a loose structure, has limited protection effect on a matrix, and is easy to adsorb aggressive ions such as chloride ions, so that local corrosion is aggravated. Under suitable environmental conditions, the gamma-FeOOH is gradually converted into the more thermodynamically stable alpha-FeOOH. The alpha-FeOOH is in a needle-shaped or flocculent microcrystalline structure, is compact in arrangement, has a low ion diffusion coefficient, can effectively inhibit the transmission of oxygen and water molecules to a metal matrix, and has strong binding force with the matrix and difficult peeling, so that the alpha-FeOOH is considered as a key component playing a main protective role in a weathering steel rust layer. Patent CN107556834a discloses a stable accelerator for a weathering steel rust layer and a use method, which adopts polyvinyl butyral resin or acrylic epoxy resin as a film forming substance, and is matched with inorganic fillers such as iron oxide red, barium sulfate and the like to prepare a coating, and is matched with an oxidation accelerator such as sodium nitrate and the like to be applied on the surface of the weathering steel in a coating mode. The technology can accelerate the generation of alpha-FeOOH to a certain extent, but basically belongs to 'covered' protection, and has obvious defects that firstly, an organic resin film prevents ion exchange and oxidation-reduction reaction between a rust layer and the outside, inhibits continuous phase change of an internal unconverted rust layer, leads to non-uniform state of stable surface layer and internal activity of the rust layer, and possibly induces under-film corrosion in the long term, secondly, the organic coating is easy to age, pulverize and peel under the actions of ultraviolet rays, temperature difference circulation, acid rain and the like, loses the protection fun