Strength of plasma coating and effect of a plasma coating on hydrogen entry

The strength of a plasma coating and the effect of the plasma coating on hydrogen entry were investigated to establish a method that provides a base material with highly resistant to hydrogen entry and embrittlement. Aluminum alloy A6061, which is highly resistant to hydrogen gas atmosphere, was employed as the coating material (300W, 17 h, ∼40μm thickness). Two types of specimen prepared by the hydrogen-charging method were adopted: the coated and uncoated specimens were (1) immersed in 20 mass% ammonium thiocyanate aqueous solution at 313K for 48 h, or (2) exposed to hydrogen gas atmosphere at 100MPa and 270 °C for 200 h. Hydrogen content measurements revealed that the A6061 plasma coating is highly resistant to hydrogen entry in corrosive environments. The coating reduced hydrogen entry by ∼50% during exposure to hydrogen gas atmosphere at 100MPa and 270 °C. Moreover, the plasma coating method was found to be applicable in the elastic deformation region of the base material.