A corrosion resistant article including an aluminum substrate and a corrosion-inhibiting cerium based corrosion inhibitor corrosion inhibiting additive on the aluminum substrate, the corrosion inhibiting additive comprising an anodic corrosion inhibitor and a cathodic corrosion inhibitor, the anodic corrosion inhibitor greater than 25 wt % of the total inhibitor.

In a method for cathodically protecting and/or passivating a metal section in an ionically conductive material such as steel reinforcement in concrete or mortar, an impressed current or sacrificial anode communicates ionic current to the metal section and a storage component of electrical energy which can be a cell, battery or capacitor is provided as a component of the anode. A current limiter is provided which prevents excess current draining the supply. This can be a semi-conductive device such as a transistor or diode is connected in the path from the anode to the metal section to limit the cathodic protection current to a value of the order of 1 milliamp. When a diode or similar device is used the current can be limited to the reverse leakage current of the diode.

The metal tank portion of an electric water heater is protected against corrosion utilizing a corrosion protection system that detects a voltage potential between the sheath portion of a tank water-immersed electric heating element and the tank. In one embodiment of the corrosion protection system the sensed sheath/tank potential is utilized to enable a user of the water heater to accurately gauge the necessity of replacing a sacrificial anode extending into the tank. In another corrosion protection system, the sensed sheath/tank potential is utilized to provide impressed current cathodic protection of the tank and also to prevent dry firing of the electric water heater.

The metal tank portion of an electric water heater is protected against corrosion utilizing a corrosion protection system that detects a voltage potential between the sheath portion of a tank water-immersed electric heating element and the tank. In one embodiment of the corrosion protection system the sensed sheath/tank potential is utilized to enable a user of the water heater to accurately gauge the necessity of replacing a sacrificial anode extending into the tank. In another corrosion protection system, the sensed sheath/tank potential is utilized to provide impressed current cathodic protection of the tank and also to prevent dry firing of the electric water heater.

The present invention provides a system and a method for providing corrosion protection of a metallic structure using time varying electromagnetic wave. The system comprises: a generator for generating electromagnetic wave having a time varying frequency, said generator having at least two output terminals in electrical connection respectively with first and second excitation sites positioned in a spaced manner on the metallic structure, allowing for subjecting the metallic structure to the electromagnetic wave; and an electric power source connected to the generator for applying a driving voltage to the generator to drive the generation of the electromagnetic wave; wherein the driving voltage and/or the frequency of the electromagnetic wave are selected such that the metallic structure is energized to form in-situ a passive oxidized species of the metal on a surface of the metallic structure, which species is insusceptible to corrosion.

An electrolysis device is provided. The electrolysis device includes a plurality of electrolysis cells that are electrically connected in series and are arranged successively at least partly in a stack direction, where the series connection is electrically couplable to an electrical energy source. The electrolysis device also includes a cell supply unit for supplying the electrolysis cells with at least one operating material and supply conduits connected to the cell supply unit and to opposite ends of the successively arranged electrolysis cells, where a negative electric potential of the electrical energy source is electrically couplable to an electric reference potential of the cell supply unit.

Corrosion protection of steel in concrete is provided by locating an anode assembly including both a sacrificial anode and an impressed current anode in contact with the concrete and providing an impressed current from a power supply to the anode. The impressed current anode forms a perforated sleeve surrounding a rod of the sacrificial anode material with an activated ionically-conductive filler material between. The system can be used without the power supply in sacrificial mode or when the power supply is connected, the impressed current anode can be powered to provide an impressed current system and/or to recharge the sacrificial anode from sacrificial anode corrosion products.

The invention relates to an electrolysis device including a plurality of electrolysis cells which are electrically connected in series and which are arranged at least partly successively in a stacking direction in a cell stack, where the series connection can be electrically coupled to an electrical energy source. A cell supply unit for supplying at least one operating medium to the electrolysis cells in normal operation and supply lines connected to the cell supply unit and to the cell stack, where a material of the supply lines include metal. The supply lines are connected to a first end of the cell stack so that the first end of the cell stack is electrically coupled to the cell supply unit, where the first end of the cell stack can be coupled to a negative electrical potential of the electrical energy source.

An intelligent system is provided for monitoring a subsea structure and delivering appropriate cathodic protection to desired areas of the subsea structure. According to an embodiment, the technique involves monitoring a cathodic protection potential level at an important location or locations of the subsea structure. Based on the data acquired via monitoring, a controller is able to apply voltage levels to the subsea structure so as to attain and modulate a desired cathodic protection level, e.g. a cathodic protection level within a range of about 800 mV to 950 mV (SCE). Consequently, undesirable overprotection and under protection are avoided and the subsea structure is adequately protected from corrosion while reducing undesirable production of hydrogen.

A corrosion resistant article including an aluminum substrate and a corrosion-inhibiting cerium based corrosion inhibitor corrosion inhibiting additive on the aluminum substrate, the corrosion inhibiting additive comprising an anodic corrosion inhibitor and a cathodic corrosion inhibitor, the anodic corrosion inhibitor greater than 25 wt % of the total inhibitor.