While there is an obvious mega trend to reduce the weight of materials, so called “light weight material”, the demand for corrosion resistance performance of surface has been continuously increasing. The thin silica-based coating film (5-10 microns) of “TOP NOBAC PRO” sprayed or dipped to the parts not only provide prevention from rust or corrosion, but also offer the state-of-the-art technology in antibacterial that affects that protecting us from the pathogenic diseases caused by bacteria. The coating film is colorless and has excellent transparency while remaining the metallic textures and colors of the base.