水素侵入防止コーティングの開発に向けた研究

抄録

Surface Coating effects against hydrogen entry into the base material were investigated. Two kinds of coating methods were used: sputtering and electrodeposition methods. In the case of the sputtering method, the S25C steel was coated with a target made by Aluminum alloy or homogeneously mixed with pure iron fine powder and pure aluminum fine powder. The sputtering condition was 200 ~ 300W and 4h. On the other hand, in the case of the electrodeposition method, S25C steel was coated with the film from aqueous solutions containing an iron(II) sulfate, nickel(II) sulfate, L-ascorbic acid, and citric acid⁽¹⁾. Two types of hydrogen-charging methods were adopted to both the coated and uncoated specimens: (1) immersed in 20 mass % ammonium thiocyanate aqueous solution at 313 K for 48 h, or (2) exposed to hydrogen gas atmosphere at 11 ~ 100 MPa and 85 ~ 270 °C for 200 h. Hydrogen contents were measured using a thermal desorption analyzer (TDA). The coating films showed good resistance against hydrogen entry in each cases exposing charge or immersion charge. In most of the cases of hydrogen gas exposing charges, the Al single coating was almost constant at ~50% regardless of pressure and temperature except for a case of low pressure, 30MPa, and low temperature, 85 oC,. Further, only when SUS304 was the base material, the effect of the coating was scarce. From the results, the hydrogen entry prevention performance is highly related to the interface between the coating part and the base material.