A new electrode and metal oxide surge arrester (MOA) with series air gap is developed, the gap is a pure air one and is composed by high voltage piercing electrode and MOA in itself.

Small amounts of boron were transferred from the electrode to weld metal by adding boron oxide or ferroboron powder to the electrode covering.

The anticorrosion mechanism of polyamine and metal interface is formed a layer of compact metal oxide film, so that the electrode potential of metal passivation;