Corrosion to a metal surface in contact with corrosion forming components within an aqueous-based fluid system may be decreased, prevented, and/or inhibited by contacting the metal surface(s) with apatite forming components and forming at least one apatite species on the surface with the apatite forming components. The apatite forming components may be or include phosphates, organophosphates and combinations thereof. In a non-limiting embodiment, the apatite forming components may further include fluorides, chlorides, calcium, and combinations thereof.

Disclosed are methods of using nitrogen-containing compounds as corrosion inhibitors. The present method is used to inhibit corrosion of a metal surface in contact with an aqueous system using 2-substituted imidazoles and 2-substituted benzimidazoles, and provides enhanced protection against corrosion of metals in the aqueous system. The method comprises the use of corrosion inhibitors that are generally resistant to halogen attack and provide good corrosion resistance in the presence of oxidizing halogen-based biocides. Formulations comprising 2-substituted imidazoles and 2-substituted benzimidazoles are also disclosed.

The present invention relates to a process for the anti-corrosion pretreatment of a multiplicity of components in series, wherein each component in the series at least partly has surfaces of zinc and undergoes successive process steps for the deposition of iron and for zinc phosphation. In the process step for the deposition of iron, the coating layer to be established is at least 10 milligrams of elemental iron per square meter of the zinc surfaces. The zinc phosphation subsequent to this deposition of iron takes place by means of an acidic aqueous composition which in addition to zinc ions, phosphate ions and free fluoride also comprises a particulate constituent dispersed in water which is at least partly composed of hopeite, phosphophyllite, scholzite and/or hureaulite, and is provided by means of an aqueous dispersion of these crystalline solids that is stabilized with at least one polymeric organic compound.

A thermally stable, solid sulfite-based treatment composition for treating water systems, particularly heated water systems, to reduce corrosion. A treatment composition comprises (1) a sulfite salt that may provide at least 50% weight active sulfite and (2) a second inorganic salt hydrate that may have a melting point of 45? C. or higher. The treatment composition does not physically degrade or experience melting when stored at temperatures of 35? C.-40? C. The treatment composition is made by mixing water and a sulfite salt at an elevated temperature, then adding a second inorganic salt while maintaining the elevated temperature until a homogenous mixture is formed, then pouring the mixture in a mold and allowing it to cure at room temperature. A preferred sulfite salt is sodium metabisulfite. A preferred second inorganic salt is dipotassium phosphate.

A method includes providing a workpiece with at least one surface having an anodized aluminum coating and a trivalent chromium sealant. The at least one surface of the workpiece is submerged in a post-treatment sealant solution for 0.5 to 20 minutes. The sealant composition consists essentially of a corrosion inhibitor, an organic complexing agent, and an oxidant.

An article includes a substrate; a first corrosion protection layer disposed on the substrate; and a second corrosion protection layer disposed on the first corrosion protection layer. The first corrosion protection layer includes a sol-gel composition and the second corrosion protection layer includes a polyurethane composition. At least one of the first or second corrosion protection layers include a corrosion inhibitor.

A process for preventing the formation of white rust on a steel surface at least partially coated with zinc includes a) bringing said surface, preferably under thermal load, into contact with an aqueous composition, the pH of which is between 6.5 and 8.5 comprising at least one organic acid of formula:
RXOH(I) wherein X represents C(O) or S(O)2, and R represents an organic chain. A composition and also to a cooling tower treated by the process are provided.

Corrosion to a metal surface in contact with corrosion forming components within an aqueous-based fluid system may be decreased, prevented, and/or inhibited by contacting the metal surface(s) with apatite forming components and forming at least one apatite species on the surface with the apatite forming components. The apatite forming components may be or include phosphates, organophosphates and combinations thereof. In a non-limiting embodiment, the apatite forming components may further include fluorides, chlorides, calcium, and combinations thereof.

The present invention relates to the field of phosphating for corrosion-protective pretreatment of zinc surfaces, being directed toward the use of largely nickel- and cobalt-free zinc phosphating solutions. The present invention makes available an alternative to trication zinc phosphating, in which the zinc surfaces of a component are firstly, before zinc phosphating, passivated with an alkaline composition containing iron(III) ions, and thereby preconditioned for a largely nickel- and cobalt-free zinc phosphating operation. In a further aspect, the invention relates to a component, in particular an automobile body, that comprises at least in part surfaces made of zinc, the zinc surfaces being covered by a two-layer system made up of a first, inner passive layer containing iron and resting on the zinc surface, and a second, outer crystalline zinc phosphate layer resting on the inner layer.

A method of suppressing corrosion of a corrodible metal surface that contacts a fluid stream in a hydrocarbon system. The method includes introducing into the fluid stream a treatment chemistry including an organometallic corrosion inhibitor having a metal and an organic carboxylic acid. The organometallic corrosion inhibitor is hydrocarbon soluble and the metal is released from the organometallic corrosion inhibitor in the presence of water or H.sub.2S.