Family health management is gradually emerging, and hyperbaric oxygen chambers are also gradually entering the public's field of vision. Hyperbaric oxygen chambers can provide convenient home care for family members and improve their quality of life. Hard Shell Hyperbaric Chamber, Hard Shell Oxygen Chamber, Hard Hyperbaric Chamber, Hard Hyperbaric Oxygen Chamber Danyang Doing Articles Co.,Ltd , https://www.dydoing.com
DOING hard shell Hyperbaric Oxygen Chamber provides an oxygen rich environment, which can increase the oxygen partial pressure and oxygen content in the human blood, promote cell metabolism, and alleviate symptoms of hypoxia. Meanwhile, sufficient oxygen helps promote tissue regeneration, thereby accelerating wound healing.
The oxygen production principle of DOING high-pressure oxygen chamber is molecular sieve oxygen production. Molecular sieve first compresses and filters the air, and then adsorbs nitrogen from the air under high temperature and pressure, leaving a high concentration of oxygen.
DOING hyperbaric oxygen cabin is equipped with two transparent observation windows, which are well lit and can provide a good visual experience for the personnel inside the cabin. There will be no shortage of light, and the cabin will not lack a sense of security for the personnel inside.
DOING high-pressure oxygen chamber is equipped with automatic and manual pressure relief valves. When the automatic pressure relief valve is not working or there is an emergency situation inside the chamber, the manual pressure relief valve can be used to manually reduce pressure and ensure safety.
The yellowing of steel plate phosphating is a common issue in the chemical conversion coating process, especially when using zinc-based phosphating solutions with oxidizing accelerators and various additives such as film-forming agents. The chemical reactions involved are complex, including ionization, hydrolysis, displacement, neutralization, precipitation, complexation, and redox reactions. Some of these reactions are catalyzed by nitrates or nitrites, making the process even more intricate. Despite this complexity, ongoing research continues to deepen our understanding of the phosphating reaction mechanism.
One key factor in accelerating the phosphating process is heating, which promotes the dissolution of electropositive metals. For example, adding a small amount of copper salt can lead to a displacement reaction, where copper deposits on the steel surface. This creates micro-cathodes that intensify electrochemical corrosion and speed up the formation of the phosphating film. Depolarizers also play an important role by preventing hydrogen from covering the crystal nuclei, allowing hydrogen atoms to be oxidized into water without hindering ion diffusion.
To enhance the deposition of the phosphating film, introducing crystalline nuclei is a common method. Adjusting the titanium salt surface before phosphating can create active centers that promote crystal growth. Without sufficient nuclei, the formation of a complete phosphating film becomes difficult. Excessive supersaturation can lead to issues like uneven film formation and defects.
Yellowing often occurs at low catalytic concentrations, where metal corrosion progresses slowly, and precipitates accumulate at micro-cathode areas. If the catalyst concentration is too low, it becomes difficult to form a complete phosphating layer, leaving the metal exposed to oxidation and resulting in yellowing. High total acidity in the phosphating solution can also cause yellowing. When the total acid concentration is too high, the buffer capacity of the solution increases, making it harder for the acidity near the workpiece surface to decrease. This leads to poor film formation and potential yellowing.
High free acid levels in the phosphating solution can also contribute to yellowing. A high free acid value (e.g., 4.2) indicates excessive acidity, which can cause the surface to oxidize and turn yellow. Surface adjustment failures, such as not properly preparing the steel before phosphating, can result in insufficient active centers, leading to a weak phosphating film that cannot protect the metal effectively.
In some cases, improper degreasing processes or incorrect use of degreasers in the adjustment tank can lead to yellowing. Additionally, if spray nozzles are blocked during phosphating, certain areas may not receive enough solution, causing localized yellowing. Adding copper or nickel salts to the phosphating solution can improve film quality by increasing the number of crystal nuclei, resulting in a finer and denser coating.
A multifunctional oil-based metal cleaning agent has been developed to address some of the challenges in pre-treatment processes. This cleaner includes surfactants, co-solvents, rust inhibitors, and bactericides, offering advantages over traditional aqueous or solvent-based cleaners. It provides fast, effective cleaning at room temperature, reduces rust risk, and is non-toxic and environmentally friendly. It is suitable for various applications, including painting, electroplating, and phosphating.
Other factors contributing to yellowing include short phosphating times, pump failures, and fast conveyor chain speeds, all of which can disrupt the uniformity of the phosphating process. Insufficient time for crystal growth can result in a weak, porous film that fails to protect the metal, leading to oxidation and discoloration.
In conclusion, the phosphating process involves several critical steps: metal dissolution, ion product concentration, nucleation, and crystal growth. Ensuring sufficient time, proper catalysts, and optimal conditions is essential for achieving a high-quality, protective phosphating film. By addressing these factors, the occurrence of yellowing and other defects can be significantly reduced.