Mechanism Verifying of Long-effect Anti-corrosion of Spray Metal Coating

40 years ago,China began to use the zinc coating for steel structures in the gate of Huaihe River.Several decades later,spray aluminum layer,and double spray layer of Zn-Al have been applied.Recently the high aluminum-containing zinc-aluminum pseudo alloy long-effect anti-corrosion layer has been obtained with the high-power,secondary air spraying.Long cycle NSS method (neutral salt spray accelerated corrosion tests) was used to prove the long effect of the coating.The scanning electron microscopy experiment,proved the hypothesis of an American scholar as “aluminum oxide coating formation as a networks and zinc oxide particles filling the grid of this networks,resulting in corrosion-resistant oxide layer”.At the same time,the reason of long-effect of corrosion-resistant zinc-aluminum pseudo alloy layers of the high-power secondary air spraying was explained.