Metal Coatings Derived from Modified Silica as Anti-Corrosion

Metal is widely used in various industrial fields such as transportation because of its physical and mechanical strength. However, during its utilization, metal materials are often damaged by corrosion due to chemical reactions between the metal surface and the surrounding environment. Coating is one way to prevent corrosion by isolating metal surfaces from the environment. Conventional anti-corrosion coatings generally use chromate and phosphate-based materials. However, this material has been banned in some countries because it is toxic to the environment. Meanwhile, other methods with the addition of more active metals such as magnesium are considered unaffordable. Therefore, the researchers developed alternative materials that are environmentally friendly and reduce costs by using metal oxide-based materials such as Silicon dioxide (SiO2). The advantage of SiO2 is that it is chemically stable and harmless. SiO2 modification produces hydrophobic properties which increase corrosion resistance. One of the methods to make SiO2 is sol-gel method. The advantages of sol-gel method are simple, affordable, capable of forming a film for attaching chemical properties, flexible for incorporation with other compounds and the coating can be applied in several ways, such as dip coating, spray coating, electrophoretic deposition (EPD), etc. As an anti-corrosion coating, products can be tested for their resistance by analyzing the corrosion rate. This paper reviews silica-based metal coatings as anti-corrosion. The scope of the discussion in this paper is the mechanism, fabrication route, application technique, characterization, and analysis of anti-corrosion ability by studying the corrosion rate of anti-corrosion silica-based coating products for metal substrates.