An underlayer coating system consists of larger particle size extenders like Chinaclay, Talc, Chalk and Barytes. The strict environmental regulation acts such as REACH (Registration, Evaluation, Authorisation and Restriction of Chemical substances ) are challenging one for coating formulators because they are not allowed to use any of hazardous materials in their coating formulations. Due to that, chromate containing coatings, hazardous solvents and hazardous additives are almost banned in many countries. Thus, a study on “Dispersion, characterisation and testing on durability performances of Nanobarytes, Nanoclay & Nanochalk in Polyurethane under layer protective coatings” is taken up for investigation. The main objective of above investigation is to replace Chromate containing coatings. This investgation was dealt in three stages such as Surface modification techniques of Nanochalk, Nanobarytes and Nanoclay;Dispersion techniques of Nanochalk, Nanobarytes and Nanoclay; Characterisation and durability performances of dispersed Nanoextenders and surface modified Nanoextenders in Polyurethane coatings.