Russia develops anti-corrosion composite coating for magnesium alloy equipment

Magnesium alloys are widely used in fields including automotive and aircraft parts manufacturing. This material is not only very light, but also very strong, but at the same time also has obvious defects such as susceptibility to corrosion and wear. Therefore, equipment made of this material has a relatively short service life and is expensive to repair or replace. To provide protection for this material, researchers are developing a coating that prevents aggressive environments from damaging magnesium alloy components and structures, as well as non-corrosion protection. However, such coatings tend to be prone to pinholes and microcracks, so that the coatings do not fully protect mechanical parts from corrosion if exposed to aggressive environments for extended periods of time. It is reported that Russian researchers used ultra-dispersed polytetrafluoroethylene. This polymer material is used in daily life for tableware non-stick coating, heat resistance, cold resistance, good elasticity and good water resistance. In addition, it is chemically more stable than all known synthetic materials and is not affected by acids and bases. The researchers applied the composite coating to magnesium alloy samples in a new way: using plasma electrolytic oxidation (PEO) technology, and then spraying the polymer. First, the surface of the alloy is coated with a ceramic-like PEO coating, then the pores and surface of the coating are evenly sprayed with ultra-dispersed PTFE powder, and finally the sample is dried in a furnace at 300 degrees Celsius. In the coating thus obtained, the defects are only 1/3 of the PEO coating, because the polymer will penetrate the pores and micro-cracks and close them. Under the protection of the composite coating, the magnesium alloy samples are more resistant to corrosion than the untreated material. If the spray is repeated, the protection will be stronger. To test the wear resistance of the coating, the researchers conducted long-term friction tests on the samples. The results show that the alloy with the composite coating loses integrity (wear) 27 times slower than the alloy with the basic PEO coating. Reporter Dong Yingbi