Marine corrosion and protection is an important problem in Marine development because the marine atmosphere and seawater corrosion are important causes of damage to coastal facilities, offshore engineering structures, and ships. Therefore, it is of great strategic significance to study the corrosion resistance and long-term protection technology of buildings in the marine environment for the human to develop and utilize the ocean.
A large number of research and application results at home and abroad show that hot spraying aluminum, zinc, and its alloy coatings are the most effective and economical protection methods. Aluminum, zinc and aluminum-zinc alloy coatings have excellent corrosion resistance. Aluminum and zinc are anodic materials for steel, and the steel substrate will be protected from corrosion by sacrificing the anode even if the coating is slightly defective. Therefore, aluminum and zinc are widely used as anti-corrosion coatings for steel components.
In June 1984, the United States used thermal spray aluminum coating technology to prevent corrosion of chains, lifts and tapered towers on the tension support platform of Hutton production equipment in the North Sea. For the high-strength steel parts, flame spraying aluminum coating not only can provide a shielding layer, and also can be used as a sacrificial anode protection leakage occurred in the area once the coating is damaged. The sealing coating can be applied to the flame spraying layer to seal the pores of the flame spraying aluminum coating, so as to improve the coating performance and prolong its service life. After eight years, the Hutton platform found no corrosion or brown leakage in the splash zone. The thickness measurement showed that the coating thickness did not decrease after the platform was installed. In addition, the aluminum coating substrate still shows the state of the original sandblasting, which indicates that the Hutton platform after thermal spraying aluminum coating has good corrosion resistance.
Thermal spraying of zinc and aluminum and its alloy coating has become a mature protection technology for offshore and offshore steel facilities, and the steel structures in the splash zone have excellent corrosion resistance performance under normal temperature and high temperature. According to the current technology level, the protection life of steel structure in splash zone is expected to be over 30 years with 200μm thermal spray aluminum coating.
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