The Effect of Oil Pollution on The Properties of Phosphate Layer and Properties of Organic Automotive Coatings

In different industries, protective oils are applied temporarily on the metal substrates to prevent corrosion damages. This layer should be removed before applying organic coatings. Alkali solution and solvent wash are the most frequently methods to remove oil from surface. Aforesaid methods can not remove this layer perfectly. As a result, always some residual protective oil remains on the metal surface. In this work the effect of this layer on properties of automotive phosphate layer was investigated using scanning electron microscope (SEM) and weight of phosphate layer. It was seen that oil pollution reduced the homogeneity of phosphate layer, changed the crystal shape of phosphate layer and decreased the weight of phosphate layer. In addition, the effect of residual oil on the different physical-mechanical properties of coating systems was investigated. It was seen that residual oil improved bending, cupping and impact properties of coating due to diffusion of the residual oil in coating layer. In the other hand, corrosion resistance decreased because of adhesion failure.