KINETIC ANALYSIS OF CRACK FORMATION IN CATHODIC ELECTRODEPOSITED COATINGS: INFLUENCE OF POLYMERIZATION TIME AND THERMAL CONDITIONS

This study investigates the influence of material properties and processing conditions on the crack length of electrophoretic coatings on cold-rolled low-carbon steel. The selected steel, identified by VDA239-100 CR4 and CR5 and DIN EN 10130 DC05 and DC06 standards, features a low carbon and titanium content, offering improved plasticity and mechanical properties. The bending test, conducted according to ISO 6860:2006 on a conical mandrel, was employed to evaluate the flexibility and mechanical integrity of the coating under controlled deformation. Statistical analyses of model adequacy, using the coefficient of determination (R²), indicate that the model explains approximately 70.31% of the variability in crack length. The study also demonstrates the application of the Design of Experiments (DOE) methodology to assess the influence of polymerization time and thermal conditions on crack formation. Graphical analysis reveals the significant effects of polymerization duration and temperature, as well as phosphating time, on the crack length, with the findings providing a deeper understanding of the factors contributing to coating behavior.