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.

The invention relates to a method for dissolving an oxide layer containing chromium, iron, nickel, and radionuclides by means of an aqueous oxidative decontamination solution, which contains permanganic acid and a mineral acid and which flows in a circuit (K1), wherein the oxidative decontamination solution is set to a pH value 2.5.

A cleaning solution for a turbine engine includes water within a range between about 68.65 percent and about 99.63 percent by volume of the cleaning solution; a first organic acidic component within a range between about 0.1 percent and about 15 percent by volume of the cleaning solution; wherein the organic acid comprises citric acid; a second organic acidic component within a range between about 0.1 percent and about 15 percent by volume of the cleaning solution; wherein the organic acid comprises glycolic acid; isoropylamine sulphonate within a range between about 0.07 percent and 0.14 percent by volume of the cleaning solution; alcohol ethoxylate within a range between about 0.035 percent and 0.07 percent by volume of the cleaning solution; triethanol amine within a range between about 0.035 percent and 0.07 percent by volume of the cleaning solution; sodium lauriminodipropionate within a range between about 0.03 percent and 1.0 percent by volume of the cleaning solution. The cleaning solution has a pH value in the range between about 2.5 and about 7.0.

A cleaning solution for a turbine engine includes water within a range between about 68.65 percent and about 99.63 percent by volume of the cleaning solution; a first organic acidic component within a range between about 0.1 percent and about 15 percent by volume of the cleaning solution; wherein the organic acid comprises citric acid; a second organic acidic component within a range between about 0.1 percent and about 15 percent by volume of the cleaning solution; wherein the organic acid comprises glycolic acid; isoropylamine sulphonate within a range between about 0.07 percent and 0.14 percent by volume of the cleaning solution; alcohol ethoxylate within a range between about 0.035 percent and 0.07 percent by volume of the cleaning solution; triethanol amine within a range between about 0.035 percent and 0.07 percent by volume of the cleaning solution; sodium lauriminodipropionate within a range between about 0.03 percent and 1.0 percent by volume of the cleaning solution. The cleaning solution has a pH value in the range between about 2.5 and about 7.0.

A grain-oriented electrical steel sheet according to an embodiment of the present disclosure includes: a forsterite layer formed on the surface of an electrical steel sheet; a groove which is formed on the forsterite layer in a direction perpendicular to a rolling direction; and a forsterite calcination layer which is formed in the direction of both ends of the electrical steel sheet on the basis of an upper end of the groove and has a width of 1.1 to 1.3 times the width of the groove.

A grain-oriented electrical steel sheet according to an embodiment of the present disclosure includes: a forsterite layer formed on the surface of an electrical steel sheet; a groove which is formed on the forsterite layer in a direction perpendicular to a rolling direction; and a forsterite calcination layer which is formed in the direction of both ends of the electrical steel sheet on the basis of an upper end of the groove and has a width of 1.1 to 1.3 times the width of the groove.

The present invention relates to a method and a system for cleaning a semiconductor substrate wherein Al is at last partially exposed on a silicon substrate and silicided with a metallic substance without damaging the Al and a silicide layer. A cleaning portion cleans the aforementioned semiconductor substrate. A delivery portion, disposed on the cleaning portion, delivers a solution to the semiconductor substrate. A sulfuric acid solution transfer path connected onto the delivery portion transfers a sulfuric acid solution and an adsorptive inhibitor solution transfer path connected to the delivery path transfers an adsorptive inhibitor having any one or more of N-based, S-based, and P-based polar groups to the delivery portion. The sulfuric acid solution and the adsorptive inhibitor may be mixed or separately transferred to come into contact with the semiconductor substrate.

A process for forming a descaling composition has the steps of macerating a bone meal with a dimethylamine solution, digesting the macerated bone meal with hydrochloric acid, neutralizing the digested bone meal with calcium oxide, treating the neutralized bone meal with sulfuric acid, and applying a refluxing treatment with dimethylamine and hydrazine hydrate. The process further includes removing the macerated bone meal solids from the dimethylamine solution and transferring the removed solids to an extraction tower prior to the step of digesting. The hydrochloric acid is circulated through the macerated bone meal. The treated bone meal and the sulfuric acid is filtered so as to produce a liquid phase and a solids phase. The liquid phase contains a phosphate amine. The dimethylamine and hydrazine hydrate are added to the liquid phase.

A process for forming a descaling composition has the steps of macerating a bone meal with a dimethylamine solution, digesting the macerated bone meal with hydrochloric acid, neutralizing the digested bone meal with calcium oxide, treating the neutralized bone meal with sulfuric acid, and applying a refluxing treatment with dimethylamine and hydrazine hydrate. The process further includes removing the macerated bone meal solids from the dimethylamine solution and transferring the removed solids to an extraction tower prior to the step of digesting. The hydrochloric acid is circulated through the macerated bone meal. The treated bone meal and the sulfuric acid is filtered so as to produce a liquid phase and a solids phase. The liquid phase contains a phosphate amine. The dimethylamine and hydrazine hydrate are added to the liquid phase.

A system for descaling heat exchanger surfaces using a varying concentration of either an acidic or alkaline solution, selecting an optimum pH value for descaling a heat exchanger according to the level of cleaning the heat exchanger requires, monitoring pH value of descaling solution during circulation through a heat exchanger, and adding chemical solution to achieve coincidence of optimum and monitored pH values during descaling operation.