Influence of Residual Protective Oil on Physical and Mechanical Properties of Automotive Coating System

It is well known that protective oils are applied temporarily on metal substrates after steel manufacturing to prevent corrosion damages. In automotive manufacturing this layer is removed before coating application. Different methods are used to remove of this layer such as alkali solution spraying and solvent wash. Aforesaid methods can not remove this layer perfectly. As a result, always some residual protective oil remains on metal surface. In this work the effect of residual oil on different physical-mechanical properties (bending, cupping, hardness and impact) and corrosion resistance of different parts of automotive coating system containing electrodeposition (ED) layer and whole paint system (including phosphate, ED, primer and top coat) 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.

Keywords:

Automotive coating , Corrosion resistance , Degreasing , Physical and mechanical properties