Pressure vessels formed from fiber composites are described. The fiber composites include fibers impregnated with a resin system containing surface-modified nanoparticles dispersed in a curable matrix resin.

A high pressure tank includes: a supplying/discharging hole; and a cap having formed therein a cap-side path which is a part of a flow path. A repelling coating interposes between a liner-side end surface facing a resin-made liner, of a flange section configuring the cap, or a flange section-facing outer surface facing the flange section, of the liner. The repelling coating is formed of a material that repels a matrix resin of a fiber-reinforced resin configuring a reinforced layer.

A hydrogen gas storage tank includes a body including a steel bulk region and a passivating metal oxide layer adjacent to the steel bulk region, the oxide layer comprising a number of metal oxide molecules, all having a morphology, wherein at least about 51 wt. % of the number of metal oxide molecules are Fe.sub.2O.sub.3 molecules having morphologies of (012), (001), and/or (110) surface facets such that the oxide layer is configured to lower hydrogen adsorption into the steel bulk region by at least 25% compared to a steel bulk region free from the passivating metal oxide layer.

A pressure vessel for holding fluids includes a tank and a coating disposed on an outer surface of the tank. The tank defines a cavity for holding fluids, and an outer surface of the tank includes a first visual characteristic. The coating includes an indicator layer, an outer layer, and a first intermediate layer. The indicator layer is disposed on the outer surface, the indicator layer including a second visual characteristic that visually contrasts with the first visual characteristic. The outer layer is disposed over the indicator layer, the outer layer including a third visual characteristic that visually contrasts with the second visual characteristic. The first intermediate layer is positioned between the indicator layer and the outer layer, the first intermediate layer being visually transparent or translucent. The disclosure also describes a coating including an indicator layer, an outer layer, and a first intermediate layer.

A method for constructing a double-shell-structured cylindrical tank having an inner tank and an outer tank includes: a step of, inside the outer tank, assembling a first structure of the inner tank excluding a lowermost level of the inner tank by alternately and repeatedly performing raising of an inner tank lateral plate using a jack-up unit and attaching of a next inner tank lateral plate below the raised inner tank lateral plate; a step of assembling a second structure serving as the lowermost level of the inner tank on an annular portion provided on a base portion of the outer tank and configured to support the inner tank; and a step of assembling the inner tank by joining the first structure and the second structure.

A method of making a fiber reinforced energetic composite is provided. The method includes providing a mold or mandrel defining a shape for the fiber reinforced energetic composite, providing an impregnated fiber layup over the mold or mandrel, and curing the impregnated fiber layup. The impregnated fiber layup includes a fiber layup and polymer resin, the fiber layup formed from a plurality of reinforcing fiber layers and an energetic polymer nanocomposite disposed adjacent one or more of the reinforcing fiber layers with the polymer resin impregnated within the reinforcing fiber layers. The energetic polymer nanocomposite includes core-shell nanoparticles entrained in a thermoplastic polymer matrix where the core-shell nanoparticles include a core made of metal and at least one shell layer made of metal oxide disposed on the core or a core made of metal oxide and at least one shell layer made of metal disposed on the core.

A hydrogen storage tank has a composite laminate wall, a hydrogen-porous layer in contact with the outer surface of the composite laminate wall and a hydrogen-non-porous layer in contact with the outer surface of the hydrogen-porous layer, the hydrogen-non-porous layer having an output port for venting hydrogen which passes through the composite laminate wall and the hydrogen-porous layer from the interior of the tank. The tank allows hydrogen which leaks through the composite laminate wall to be collected and re-used. The invention also allows for the rate of hydrogen leakage from the tank to be measured, providing a measure of the structural integrity of the tank.

The present invention relates to a method for storing, in a closed container, a composition comprising 1,1,1,2,3,3-hexafluoropropane in a liquid/gas state composed of a liquid phase and of a gas phase, characterized in that i) a stream comprising 1,1,1,2,3,3-hexafluoropropane is injected into said container, said stream comprising an oxygen concentration of at most 5000 ppm by volume at a temperature of 25° C., and ii) the container is closed after injection of said stream. The present invention also relates to a container for storing 1,1,1,2,3,3-hexafluoropropane.

A method of producing a barrier layer of a pressure vessel includes applying the barrier layer to a liner and/or to a fiber-reinforced layer of the pressure vessel while a pressure difference between the internal volume and the surroundings of the pressure vessel is being maintained.

A composite pressure vessel liner suitable for use in a composite pressure vessel for storing high-pressure hydrogen is provided. The composite pressure vessel liner is made of a steel material including: a predetermined chemical composition; and a metallic microstructure in which an area fraction of martensite at a position of ¼ of a wall thickness on an inner side is 30% or more, a total area fraction of martensite and bainite at the position of ¼ of the wall thickness on the inner side is 95% or more, and a total area fraction of martensite and bainite in a wall thickness center part is 95% or more, wherein the composite pressure vessel liner has a wall thickness of 20 mm or more in a longitudinal center part, and a tensile strength of 850 MPa or more in the wall thickness center part.