What are the reasons why aluminum profiles can indicate corrosion?
The reason why we choose to use aluminum profiles for decoration is because their structure is relatively stable and they are more resistant to corrosion during long-term use. However, corrosion may occur on the surface of some aluminum profiles, mainly due to the incorrect proportion of manufacturing materials used during the processing and manufacturing of aluminum profiles.
1. The addition ratio of magnesium and silicon varies during the casting process, such as the presence of some excess silicon, which forms ternary compounds in aluminum alloys in addition to a small amount of silicon in the free state. These insoluble or free impurity phases formed in alloys often aggregate at grain boundaries, weakening their strength and toughness, becoming the weakest link in corrosion resistance, where corrosion first occurs.
2. During the melting process, although the addition ratio of magnesium and silicon is within the range specified by the standard, sometimes due to uneven and insufficient stirring, the distribution of silicon in the melt is uneven, with locally enriched and depleted areas. It is directly reflected in aluminum profile products. When there is a small amount of free silicon in the aluminum matrix, it not only reduces the corrosion resistance of the alloy, but also coarsens the grain size of the alloy.
3. Improper control of various process parameters during extrusion, such as excessive preheating temperature of the billet, metal extrusion flow rate, air cooling strength during extrusion, aging temperature, and insulation time, can easily lead to silicon segregation and dissociation, resulting in magnesium and silicon not fully becoming Mg2Si phases, while some free silicon exists.
In short, if aluminum profiles are prone to surface corrosion during use, it is still due to the low quality standards of aluminum profiles during production. Therefore, when choosing aluminum profiles, we should go to a reputable manufacturer for better protection
