Performance Of Epoxy Based Paints In The Protection Of Steel Constructions Against Corrosion

摘要

Many research is done on corrosion protection of steel.The most common method for corrosion protection of steel is application of epoxy based primers and aliphatic polyurethane based top coats. When paint is applied onto steel, there are issues to be considered, i.e. surface preparation and application methods. The most common methods for surface preparation are abrasive blasting and mechanical cleaning. Brush, roller or spraying are the most frequent application techniques. 8 different paint systems were created for this research. TS EN ISO standards (Turkish version of ISO standards) were taken into account for applications and tests, which came up very often in the literature. Field tests and salt spray tests were conducted according to TS EN ISO standards. Both sandblasting at SA 2 ½ degree and mechanical cleaning at St 2 degree methods were used for sample preparation. Different epoxy based primer formulations were applied on panels. Aliphatic polyurethane based top coats were also applied onto some of them. Paint was applied with airless pistol for field samples and with a brush for salt spray test. The unique paint formulations of Duratek Protective Systems (a local paint producer) were used. Field tests conducted in Kalamis, Gebze and Dilovasi took almost 14 months. Salt spray tests were conducted in 480, 720 and 960 hour intervals. All samples were evaluated according to TS EN ISO standards at the end of tests. A correlation can be set between field tests and salt spray tests, when systems are to be compared with each other relatively. However, no one can conclude on how long a paint system would last on field according to the results of salt spray testing. Corrosion rate was also calculated for different fields. Kalamis had the slowest corrosion rate and samples on different fields confirmed that result. For the right choice of system, if sandblasting is possible, System 3 with zinc rich primer should be used. If not, System 4 with surface tolerant epoxy primer can be used. These are the most economical solutions for long term purposes.