The Effect of Different Accelerators on the Corrosion Protection of a Surface Coating on Spheroidal Graphite Cast Iron (Ductile Iron)

Abstract

This study investigates the structure and composition of the zinc phosphate coating formed on the surface of nodular cast iron as well as the corrosion resistance of the electrophoretic paint applied to the conversion layers when nitrite-based and nitroguanidine accelerators are used. In the case of different accelerators, the structure of the zinc phosphate layer that forms when exposed to low, normal and high dosages was examined. This type of casting, in addition to steel casting, is commonly used in the production of agricultural vehicles due to its favorable mechanical properties. Although the majority of studies have summarized its application in the automotive industry by focusing on the phosphating of steel, galvanized steel and aluminum-based alloys, on complex vehicle assembly lines, cast iron is also used in phosphating processes that occur simultaneously. During our investigation into the use of different accelerators, a different crystal structure formed on the surface of the cast iron but did not affect the corrosion resistance of the electrophoretic painted samples.