Performance evaluation of zinc rich primer based on soluble silicates

Abstract

Zinc rich primers are now a par of the most effective corrosion protective systems for steel under different environmental conditions. There are three types of inorganic vehicles (1) which are currently used in countries abroad for zinc rich primers and they are (i) inorganic post curing vehicles which are water based such as alkali silicates (ii) inorganic self curing vehicles which include soluble alkali silicates, quaternary silicates, polymeric modifications of these silicates, titanates etc. Work was carried at NML on the development and evaluation of zinc rich primer based on soluble silicate and the results presented here encompass the laboratory investigations carried during developmental work and evaluation studies made by atmospheric exposure of the primer at three different places viz. Jamshedpur, Digha and Madras. Other published data on some protective systems exposed under similar conditions are included here for comparison. It is concluded from the laboratory and atmospheric exposure studies that the zinc rich primer developed at NML has proved its performance in protection of steel and it can be an extremely good sacrificial primer steel protection under aggressive environment. (Dr. P. Prabhakaram, Shri A.K. Dey, S. Rao Addanki and D.K. Khan, National Metallurgical Laboratory)