FEATURES OF CHEMICAL PHOSPHATING OF CAST IRON PARTS IN WATER SUPPLY SYSTEMS

Abstract

The work concerns the increase of corrosion resistance of parts made of cast iron by powder metallurgy in conditions of not constant water flow. The analysis of scientific researches and publications of existing developments of ways of drawing and structures of protective coverings for pig-iron and steel details is carried out. There are advantages and disadvantages Zn, Zn-Ni and Zn-Ni-P coatings. Peculiarities of electrolytic coating and chemical deposition coatings are noted. The advantages and disadvantages of these methods for applying protective coatings for mass-produced parts are presented. The analysis of phosphate coatings is carried out, their advantage in the conditions of mass production is substantiated. The methods and mechanism of phosphating process, existing regimes and compositions of electrolytes for obtaining phosphate film are considered in the work. The results of research on the application of phosphate films and determine their corrosion resistance in the climate chamber are presented. Phosphating technology has been improved to obtain a corrosion-resistant phosphate film on cast iron parts made by powder metallurgy.