These M8 × 80 Zinc Plate Hex Screws are used for fastening together numerous types of material or to be fastened in to pre-tapped holes Widely used in many engineering applications Zinc coatings prevent oxidation of the protected metal to create a longer lasting finish It does this by forming a barrier and by acting as a sacrificial anode if this barrier is damaged Zinc oxide is a fine white dust that (in contrast to iron oxide) does not trigger a breakdown of the substrates surface integrity as it is formed The zinc oxide, if left intact, 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