Can polishing improve the corrosion resistance of thermos?
Polishing can improve the corrosion resistance of thermos for the following reasons:
Principle
Polishing makes the surface of the thermos smooth and flat by physical or chemical methods, reducing surface defects such as pits, scratches and oxide layers. These defects are potential starting points for corrosion because they can accumulate moisture, oxygen and pollutants, accelerating the oxidation and corrosion process of the metal. After polishing, the surface defects are reduced, and the chance of contact between the corrosive medium and the metal is reduced, thereby slowing down the corrosion rate.
Integrity of the passivation film
The corrosion resistance of stainless steel thermos mainly depends on the passivation film formed on its surface. Polishing can improve the integrity of the passivation film, making it more uniform and dense. The passivation film is a thin and stable oxide layer that can effectively prevent the contact between the corrosive medium and the metal matrix. During the polishing process, the microscopic unevenness of the surface is removed, and the formation of the passivation film in these areas is more complete, thereby improving the corrosion resistance of the thermos.
Surface smoothness
Polishing makes the surface of the thermos smoother and reduces the adhesion and penetration of the corrosive medium. Smooth surfaces are less likely to accumulate moisture, oxygen, and contaminants, which are the main factors that cause corrosion. In addition, smooth surfaces are also easier to clean and maintain, further reducing the risk of corrosion.
Limitations
Although polishing can improve the corrosion resistance of thermos bottles, it is not a panacea. In some special environments, such as high salinity or high humidity environments, the corrosion resistance of thermos bottles will still be challenged. In addition, polishing cannot completely eliminate all surface defects, and some tiny defects may still exist, becoming a potential starting point for corrosion. Therefore, in addition to polishing, other methods need to be combined, such as using high-quality stainless steel materials, proper heat treatment and surface coating, to further improve the corrosion resistance of thermos bottles.