Hydrogen blistering and hydrogen-induced cracking in amorphous nickel phosphorus coating

Hydrogen blistering and hydrogen-induced cracking in amorphous Ni–P coating were studied. The results showed that hydrogen blistering and hydrogen-induced cracking in Ni–P coating could form during cathodic charging. Hydrogen blister could nucleate through hydrogen atoms diffusing into free volume cavity besides preexisted void. With increasing hydrogen pressure, shear bands appeared on the surface of hydrogen blister, and then hydrogen-induced cracking initiated and propagated along the wall of hydrogen blister.