A method is disclosed for treating an anodized metal surface. According to the method, polynuclear clusters comprising aluminum oxide hydroxide are applied to the anodized metal surface.

A corrosion-resistant coating on an aluminum-containing substrate such as an aluminum substrate, an aluminum alloy substrate (e.g., AA 2024, AA 6061, or AA7075), or other aluminum-containing substrate includes a corrosion inhibitor-incorporated ZnAl layered double hydroxide (LDH) layer and a sol-gel layer. A zinc salt and a corrosion inhibitor (e.g., a salt of an oxyanion of a transition metal such as a vanadate) is dissolved to form a zinc-corrosion inhibitor solution, and the substrate is immersed in or otherwise contacted with the solution to form the corrosion inhibitor-incorporated ZnAl LDH layer on the substrate. A sol-gel composition is applied on the corrosion inhibitor-incorporated ZnAl LDH layer of the substrate to form a sol-gel layer, and the sol-gel layer is cured.

A corrosion-resistant coating on an aluminum-containing substrate such as an aluminum substrate, an aluminum alloy substrate (e.g., AA 2024, AA 6061, or AA7075), or other aluminum-containing substrate includes a corrosion inhibitor-incorporated ZnAl layered double hydroxide (LDH) layer and a sol-gel layer. A zinc salt and a corrosion inhibitor (e.g., a salt of an oxyanion of a transition metal such as a vanadate) is dissolved to form a zinc-corrosion inhibitor solution, and the substrate is immersed in or otherwise contacted with the solution to form the corrosion inhibitor-incorporated ZnAl LDH layer on the substrate. A sol-gel composition is applied on the corrosion inhibitor-incorporated ZnAl LDH layer of the substrate to form a sol-gel layer, and the sol-gel layer is cured.

A corrosion-resistant coating on an aluminum-containing substrate such as an aluminum substrate, an aluminum alloy substrate (e.g., AA 2024, AA 6061, or AA7075), or other aluminum-containing substrate includes a corrosion inhibitor-incorporated ZnAl layered double hydroxide (LDH) layer and a sol-gel layer. A zinc salt and a corrosion inhibitor (e.g., a salt of an oxyanion of a transition metal such as a vanadate) is dissolved to form a zinc-corrosion inhibitor solution, and the substrate is immersed in or otherwise contacted with the solution to form the corrosion inhibitor-incorporated ZnAl LDH layer on the substrate. A sol-gel composition is applied on the corrosion inhibitor-incorporated ZnAl LDH layer of the substrate to form a sol-gel layer, and the sol-gel layer is cured.

A corrosion-resistant coating on an aluminum-containing substrate such as an aluminum substrate, an aluminum alloy substrate (e.g., AA 2024, AA 6061, or AA7075), or other aluminum-containing substrate includes a corrosion inhibitor-incorporated ZnAl layered double hydroxide (LDH) layer and a sol-gel layer. A zinc salt and a corrosion inhibitor (e.g., a salt of an oxyanion of a transition metal such as a vanadate) is dissolved to form a zinc-corrosion inhibitor solution, and the substrate is immersed in or otherwise contacted with the solution to form the corrosion inhibitor-incorporated ZnAl LDH layer on the substrate. A sol-gel composition is applied on the corrosion inhibitor-incorporated ZnAl LDH layer of the substrate to form a sol-gel layer, and the sol-gel layer is cured.

A synthetic caustic composition for use in oil & gas industry activities, said composition comprising: metal hydroxides; an amino acid; urea; a sodium silicate and water.

A synthetic caustic composition for use in oil & gas industry activities, said composition comprising: metal hydroxides; an amino acid; urea; a sodium silicate and water.

A method of producing a hot-dip Zn alloy-plated steel sheet includes: dipping a base steel sheet in a hot-dip Zn alloy plating bath to form a hot-dip Zn alloy plating layer on a surface of the base steel sheet; and contacting an aqueous solution containing a water-soluble corrosion inhibitor with a surface of the hot-dip Zn alloy plating layer to cool the base steel sheet and the hot-dip Zn alloy plating layer having a raised temperature through formation of the hot-dip Zn alloy plating layer. A temperature of the surface of the hot-dip Zn alloy plating layer when the aqueous solution is to be contacted with the surface of the hot-dip Zn alloy plating layer is equal to or more than 100 C. and equal to or less than a solidifying point of the plating layer. The aqueous solution containing the water-soluble corrosion inhibitor satisfies the Equation [{(Z.sub.0Z.sub.1)/Z.sub.0}10020].

A method of producing a hot-dip Zn alloy-plated steel sheet includes: dipping a base steel sheet in a hot-dip Zn alloy plating bath to form a hot-dip Zn alloy plating layer on a surface of the base steel sheet; and contacting an aqueous solution containing a water-soluble corrosion inhibitor with a surface of the hot-dip Zn alloy plating layer to cool the base steel sheet and the hot-dip Zn alloy plating layer having a raised temperature through formation of the hot-dip Zn alloy plating layer. A temperature of the surface of the hot-dip Zn alloy plating layer when the aqueous solution is to be contacted with the surface of the hot-dip Zn alloy plating layer is equal to or more than 100 C. and equal to or less than a solidifying point of the plating layer. The aqueous solution containing the water-soluble corrosion inhibitor satisfies the Equation [{(Z.sub.0Z.sub.1)/Z.sub.0}10020].

Improved corrosion inhibitors for well brines include a phosphonate or salts thereof, and a gluconic acid or salts thereof. The inhibitors are normally injected downhole into the brines. The most preferred phosphonates are amine polyphosphonates, used in combination with alkali metal salts of gluconic acid.