AN EXPERIMENTAL-STUDY ON THE POROSITY OF POWDER COATINGS IN A FLUIDIZED-BED

This paper presents the experimental results of a study on the porosit y of powder coatings in a laboratory fluidized bed. A commercial paint powder, Levasint(R) S31, was used to coat copper cylinders of differe nt diameters. The effects of process variables such as coating tempera ture, air velocity and dipping time on the porosity of the coating wer e studied. The porosity and thickness were measured by image analysis. It is found that coating temperature plays an important role in deter mining the quality of the coating. The minimum temperature required fo r Levasint S31 to achievE 5% or less porosity is about 200 degrees-C. The air velocity and dipping time are also found to have significant e ffects on the porosity.