Features of the corrosion behavior of castings from cast iron in corrosive medium

The work is devoted to study of corrosion kinetics and mechanism of the gray and chromed cast iron in acidic and neutral environments. The relevance of work is caused by the necessity of selection of anticorrosion protection of these alloys at their operation in different environments. The investigations was carried out by gravimetric, microscopic and photometric methods. It was noted that the destruction of the alloys in these media proceeds according to the electrochemical mechanism based the analysis of the kinetic dependences of the corrosion process. The results of a study of the microstructure of the investigated alloys before and after corrosion tests are given. The authors found that ferrite and graphite are present in the structure of gray iron, while the structure of chromium iron consists of a solid solution of chromium in iron and carbides. Particular attention is paid to the effect of the chemical composition of the electrolyte on the corrosive behavior of the gray and chromed cast iron. It was found that vanadate ions are activators of the corrosion process, and cysteine and methionine are inhibitors. It is shown that the inhibitors used have a sufficiently high protective effect with respect to the investigated alloys. The obtained data are confirmed by the results of the analysis of the corrosion products of alloys made by photometric method.