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.

A method includes immersing an article comprising a yttrium based oxide in an acidic cleaning solution comprising water and 1-10 mol % HF acid. A portion of the yttrium based oxide is dissolved by the HF acid. A yttrium based oxy-fluoride is formed based on a reaction between the HF acid and the dissolved portion of the yttrium based. The yttrium based oxy-fluoride is precipitated onto the article over the yttrium based oxide to form a yttrium based oxy-fluoride coating. The acidic cleaning solution may include a yttrium based salt, which may additionally react with the HF acid to form more of the yttrium based oxy-fluoride.

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.

The present invention provides a zinc coating-forming method for drawing of metallic pipes, including a degreasing step of degreasing a material to be drawn, which is composed of any one of aluminum, an aluminum alloy, copper, and a copper alloy; a first oxidation step of forming an oxide coating on a surface of the material to be drawn, which has been degreased in the degreasing step; and a second oxidation step of forming a zinc coating on the material to be drawn, which has been coated with an oxide.

The present invention provides a zinc coating-forming method for drawing of metallic pipes, including a degreasing step of degreasing a material to be drawn, which is composed of any one of aluminum, an aluminum alloy, copper, and a copper alloy; a first oxidation step of forming an oxide coating on a surface of the material to be drawn, which has been degreased in the degreasing step; and a second oxidation step of forming a zinc coating on the material to be drawn, which has been coated with an oxide.

The present invention provides a decontamination method including the steps of decontaminating an object containing radioactive contaminated metals or alloys with a chemical decontamination agent comprising sulfuric acid (H.sub.2SO.sub.4) and forming a Ba or Sr precipitate by adding Ba or Sr cation and hydroxyl ion or halogen anion salts to the decontamination waste water.

The present invention also provides a kit for decontamination including a chemical decontamination agent including sulfuric acid (H.sub.2SO.sub.4) to decontaminate an object containing radioactive contaminated metals or alloys and Ba or Sr cation and hydroxyl ion or halogen anion salts to be added to the decontamination waste water to form a precipitate.

The present invention provides a decontamination method including the steps of decontaminating an object containing radioactive contaminated metals or alloys with a chemical decontamination agent comprising sulfuric acid (H.sub.2SO.sub.4) and forming a Ba or Sr precipitate by adding Ba or Sr cation and hydroxyl ion or halogen anion salts to the decontamination waste water.

The present invention also provides a kit for decontamination including a chemical decontamination agent including sulfuric acid (H.sub.2SO.sub.4) to decontaminate an object containing radioactive contaminated metals or alloys and Ba or Sr cation and hydroxyl ion or halogen anion salts to be added to the decontamination waste water to form a precipitate.

Described herein is a simplified process for a pretreatment of metallic substrates for cold forming. Also described herein are a corresponding reactive lubricant, a metallic substrate which has been pretreated by the process, and a method of using the pretreated metallic substrate.

Described herein is a simplified process for a pretreatment of metallic substrates for cold forming. Also described herein are a corresponding reactive lubricant, a metallic substrate which has been pretreated by the process, and a method of using the pretreated metallic substrate.