Which metal is primarily used as a coating to protect against rust and corrosion in construction?

Zinc is primarily used as a coating to protect against rust and corrosion in construction due to its unique properties. When zinc is applied to steel or iron in a process known as galvanization, it creates a barrier that protects the underlying metal from moisture and air, which are the primary causes of rust. Additionally, zinc has a sacrificial property, meaning that if the coating is scratched or damaged, the exposed steel or iron will still be protected as zinc will corrode preferentially before the underlying metal does.

In construction, this galvanization process significantly extends the life of steel structures and components, making it a widely preferred method for ensuring durability in environments where corrosion could be a concern. Other metals listed, while they may have some corrosion resistance, do not provide the same level of protection through the methods commonly used in construction.