A multifunctional coating method involves cleaning a surface, applying a layer of corrosion-resistant alloy coating to the surface, and applying an oleo-hydrophobic composite coating over the corrosion-resistant alloy coating. An oil and gas pipe has an inner surface with a multifunctional coating applied using the multifunctional coating method, and has an inner oleo-hydrophobic composite coating, beneath the inner oleo-hydrophobic composite coating a corrosion-resistant alloy coating, and beneath the corrosion-resistant alloy coating untreated pipe or any other metallic substrate.

A multifunctional coating method involves cleaning a surface, applying a layer of corrosion-resistant alloy coating to the surface, and applying an oleo-hydrophobic composite coating over the corrosion-resistant alloy coating. An oil and gas pipe has an inner surface with a multifunctional coating applied using the multifunctional coating method, and has an inner oleo-hydrophobic composite coating, beneath the inner oleo-hydrophobic composite coating a corrosion-resistant alloy coating, and beneath the corrosion-resistant alloy coating untreated pipe or any other metallic substrate.

An aqueous synthetic acid composition for use in oil industry activities, said composition comprising: lysine and hydrogen chloride in a molar ratio ranging from 1:3 to 1:12.5, preferably from more than 1:5 to 1:8.5; it can also further comprise a metal iodide or iodate; an alcohol or derivative thereof Said composition demonstrates advantageous properties over known synthetic acids at temperatures above 90 C. Said composition is useful in various oil and gas industry operations. Preferred embodiments of said composition providing substantial advantages in matrix acidizing by increasing the effectiveness of wormholing compared to conventional mineral acids such as HCl.

Provided is a martensitic stainless-steel sheet having a reduced anisotropy in workability and fatigue resistance which are attributable to oxide based inclusions. A martensitic stainless-steel sheet which has a steel composition that contains, in terms of mass %, 0.030 to 0.300% C, 0.20 to 2.50% Si, 0.15 to 4.00% Mn, 0.01 to 1.00% Ni, 11.00 to 15.00% Cr, 0.001 to 0.100% N, 0.0001 to 0.0350% Al, 0 to 0.50% V, 0 to 0.50% Nb, 0 to 0.50% Ti, 0 to 0.020% B, and a balance of Fe and unavoidable impurities, and that has a value of max, determined by the following equation (1), of 80.0 or greater, and in which oxide based inclusions are observed in the metallographic structure, the oxide based inclusions having a converted composition comprising up to 30 mass % or less Al.sub.2O.sub.3, 20 to 60 mass % SiO.sub.2, and 15 to 70 mass % MnO.

Provided is a martensitic stainless-steel sheet having a reduced anisotropy in workability and fatigue resistance which are attributable to oxide based inclusions. A martensitic stainless-steel sheet which has a steel composition that contains, in terms of mass %, 0.030 to 0.300% C, 0.20 to 2.50% Si, 0.15 to 4.00% Mn, 0.01 to 1.00% Ni, 11.00 to 15.00% Cr, 0.001 to 0.100% N, 0.0001 to 0.0350% Al, 0 to 0.50% V, 0 to 0.50% Nb, 0 to 0.50% Ti, 0 to 0.020% B, and a balance of Fe and unavoidable impurities, and that has a value of max, determined by the following equation (1), of 80.0 or greater, and in which oxide based inclusions are observed in the metallographic structure, the oxide based inclusions having a converted composition comprising up to 30 mass % or less Al.sub.2O.sub.3, 20 to 60 mass % SiO.sub.2, and 15 to 70 mass % MnO.

A method of decontaminating metal surfaces in a cooling system of a nuclear reactor comprises: an oxidation step, comprising at least one acidic oxidation step and at least one alkaline oxidation step wherein metal oxides and radioisotopes on the metal surfaces are contacted with aqueous permanganate oxidant solutions; followed by a decontamination step wherein an aqueous solution comprising oxalic acid, formic acid, citric acid, tartaric acid, picolinic acid, gluconic acid glyoxylic acid or mixtures thereof is used to dissolve at least part of the metal oxides and radioisotopes; and a cleaning step wherein radioisotopes are immobilized on an ion exchange resin; wherein at least one treatment cycle includes a high temperature oxidation step, wherein the permanganate oxidant solution is kept at a temperature of at least 100 C.

A method of decontaminating metal surfaces in a cooling system of a nuclear reactor comprises: an oxidation step, comprising at least one acidic oxidation step and at least one alkaline oxidation step wherein metal oxides and radioisotopes on the metal surfaces are contacted with aqueous permanganate oxidant solutions; followed by a decontamination step wherein an aqueous solution comprising oxalic acid, formic acid, citric acid, tartaric acid, picolinic acid, gluconic acid glyoxylic acid or mixtures thereof is used to dissolve at least part of the metal oxides and radioisotopes; and a cleaning step wherein radioisotopes are immobilized on an ion exchange resin; wherein at least one treatment cycle includes a high temperature oxidation step, wherein the permanganate oxidant solution is kept at a temperature of at least 100 C.

Novel acid-based chemistries that can be used in various cleaning, de-scaling, rust-removal, brightening, etching and other similar applications, including, but not limited to, those based upon hexafluorozirconic acid and other additives, such as urea in some applications, which are effective for a wide range of applications, while avoiding the health, safety and environmental issues that are often associated with the use of hydrochloric acid and other toxic chemistries.

Novel acid-based chemistries that can be used in various cleaning, de-scaling, rust-removal, brightening, etching and other similar applications, including, but not limited to, those based upon hexafluorozirconic acid and other additives, such as urea in some applications, which are effective for a wide range of applications, while avoiding the health, safety and environmental issues that are often associated with the use of hydrochloric acid and other toxic chemistries.

Disclosed is a conversion composition containing a trivalent chromium cation in an amount of 0.001 g/L to 20 g/L. Also disclosed is a system for treating a metal substrate that includes the conversion composition and a sealing composition comprising a lithium cation. Also disclosed is a method for treating a metal substrate that includes contacting at least a portion of a surface of the substrate with the conversion composition and then contacting at least a portion of the surface of the substrate with the sealing composition. Also disclosed is a substrate obtainable by treatment with the system and/or obtainable by the method of treating.