Nano-structured Thin Films for Hydrogen-Permeation Barrier Applied on AISI 1018 Steel Used in Petroleum Applications

Abstract

 A third coating layer gives an acceptable adhesion force with the highest deposition rate.  Nano-structured coating increased bulk AISI 1018 steel tensile strength after the hydrogen charging process.  Double layer of Ti and TiO2+Al2O3 coat gives a 20 percent increase in tensile strength after HC for AISI 1018 steel.  The layer of ceramic coatings TiO2withAl2O3 as coating Nano-structured thin films can improve the hydrogen permeation resistance  The Nano titanium layer showed the main portion in bondingHydrogen embrittlement is a diffusible Hydrogen that is harmful to the toughness of iron. It follows, therefore, that the harmful influence of diffusible Hydrogen can be mitigated by preventing its entry into steel. This approach was achieved by using three coating layers as a coating nanostructure thin layer by DC sputtering on steel structural (AISI l018) and hydrogen charging (HC) effect on uncoated and different Nano coated tensile specimens. The first layer was Titanium as a bonding layer, the second layer was TiO2 with Al2O3, and the third layer was Al2O3. Using a titanium Nano layer coating on AISI1018 steel tensile specimens increased the tensile strength from 570 to 659 M Pa with 16 hours of charging, which is considered a good increase. In contrast, the elongation remained in a steady -state with little difference in values compared to changing the charging time and the coating of the double layer. Furthermore, it was found that samples coated with TiO2 and Al2O3 by the DC method had advanced hydrogen embrittlement resistance and increased tensile strength (from 565 to 680 M Pa with 8 hours of charging process). M oreover, the maximum adhesion value was related to the triple layer at 596 psi, and the lowest value was 309 psi using the titanium layer alone. The coating time was 5 hours of the sputtering process for all specimens.The coating layers are considered a good barrier for hydrogen permeation through steel structures (AISI 1018).