ESEM observation of the process of hydrogen generation around the micro-droplets forming on AZ91 magnesium alloy

The process of hydrogen generation around micro-droplets on as-cast AZ91 magnesium alloy in an atmosphere of water vapor was in situ observed using an environmental scanning electron microscope (ESEM). The procedure for hydrogen generation was described. It indicated that the cathodic or anodic location gradually changed with the generation of hydrogen bubbles and the formation of corrosion products.