Experimental Study of effect of Powder Coating thickness and layers on Hardness and Corrosion properties of Carbon Steel Material

Abstract

Powder coating is one of the coating techniques that are widely used today as a substitute for coating using liquid painting. In this research, we report on the effect of the various layers of powder coating on the hardness and corrosion rate of the material. Three different layers of variation were observed with 1, 2, and 4 layers to obtain the best results. The cleaning process was applied before coating the samples. The coating process was performed in a special room/box to avoid contact with air and contamination from the outside environment with a spraying distance of about 20-30 cm. The morphology is compact and bigger grains are seen to be emerging in the 1 layer deposition. Many grains are visible, and uniform grains are distributed in the 2 layers deposited. For the 4 layers, due to higher layer deposition incorporation, the grain size is seen to be enlarged due to the merging of smaller grains with each other ultimately increasing the grain size. The uncoated material has a corrosion rate of 0.505 mm/year which means fair for the relative corrosion resistance. The coated samples have a corrosion rate of 0.353, 0.252, and 0.354 mm/year for the 1 layer, 2 layers, and 4 layers, respectively.  Based on the calculation, the average number of the Rockwell hardness of un-coated and coated samples for the 1 layer, 2 layers, and 4 layers,   respectively were estimated at about 70, 78, 79, and 58 HRB, respectively. The highest average hardness value is in sample B with 2 layers of 79 HRB. The lowest average hardness value is in sample B with 2 layers of 58 HRB. The lowest performance of sample D with 4 layers confirms the result as shown in the corrosion rate result.