side impact beams
Passivation is a kind of passive film, due to the effect of metal and oxide, the passive film on the metal surface is very thin, dense, good coverage, strong adsorption. Is usually a metal oxide, usually of metal oxide compound. It will be completely separate metal and corrosion media, prevent metal contact with the corrosive medium, to dissolve metal ground to a halt, passivity, anti-corrosion effect.