Used to prevent oxidation of the protected metal by forming a barrier and by acting as a sacrificial anode if this barrier is damaged.

 

Zinc oxide is a fine white dust that does not cause a breakdown of the substrate's surface integrity as it is formed. 

 

If undisturbed, can act as a barrier to further oxidation, in a way similar to the protection afforded to aluminum and stainless steels by their oxide layers.

 

The majority of hardware parts are zinc plated, rather than cadmium plated.