喷涂金属层长效防腐蚀机理的证明

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

40多年前,我国开始在淮河闸门上使用喷锌保护钢结构,以后几十年中,喷铝层、先喷锌后喷铝双层工艺均获得应用,最近用大功率二次风喷涂,得到高含铝量的锌铝伪合金长效防腐蚀涂层。中外合作进行了长周期(16000h)中性盐雾加速试验,证明了该防蚀涂层的长效性能。针对美国学者提出的"三氧化二铝在涂层背面形成网络,氧化锌颗粒填塞网格,形成耐腐蚀氧化物层",通过扫描电镜试验,分别测出涂层背面的铝、锌和氧化物的含量,证明在背面化学成分中铝和氧化物总原子含量达到70%,因而解释了为什么大功率二次风喷涂的锌铝伪合金耐腐蚀层能够长效。

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 zincaluminum pseudo alloy layers of the high-power secondary air spraying was explained.