Search Results for phosphating

This article focuses on the types, composition, and applications of phosphate coatings and describes the characteristics of phosphate-coated ferrous and nonferrous materials, including steel and aluminum. It addresses five successive process fundamentals: cleaning, rinsing, phosphating, rinsing after phosphating, and chromic acid rinsing. The article describes the techniques for controlling the chemical composition of various phosphating solutions. It discusses the equipment and factors that influence equipment requirements in immersion and spray systems. The article also describes the controlling procedures of coating weight and crystal size. It provides guidelines for choosing phosphate coatings based on application, coating weight requirements, and recommended process parameters. The article concludes with a discussion on safety precautions and the treatment of effluents from phosphating plants.

Phosphating is used in the metalworking industry to treat substrates like iron, steel, galvanized steel, aluminum, copper, and magnesium and its alloys. This article provides an overview of the types, uses, and theory of phosphate coatings and their formation. It also discusses the composition of phosphating baths, phosphate layers, and their analysis, as well as the process hardware necessary to realize these treatments. A summary of the different types of phosphate layers is tabulated, and the chemical formulas for a number of different phosphate compounds that are theoretically possible in crystalline phosphate layers are illustrated. The article presents four chemically important phosphating steps, namely, cleaning, activation or conditioning, phosphating, and posttreatment plus standard rinsing. It describes the physical and chemical properties by gravimetric analysis, chemical analysis, structure and morphology, thermal analysis, and alkaline resistance.

Calcium phosphates react to form more stable salts in aqueous solutions. This phenomenon has been applied to the solidification process for the dental and medical cement calcium phosphate cement, which consists of multiple phases of calcium phosphates and calcium salts; solidification occurs by the formation of hydroxyapatite. Dicalcium phosphate consists of crystal water along with anhydrous and dihydrate salts. This article summarizes research achievements regarding dicalcium phosphate dihydrate (DCPD) production with controlled morphology and reactivity, including effects of an additive and of production conditions on precipitation. It also summarizes achievements made in the hybridization of nano-apatite onto DCPD particles.