Polyamide powder coating of copper substrates: Impact of process parameters on the surface properties, the adhesion strength and the interface microstructure

Impact of Sterilization on the Adhesion Properties of a Polyamide 11 Coating on Textured Metal Substrates

“…For this purpose, the force needed to tear out the PA11 coating was recorded as the scraper runs along the copper substrate which was preheated to 270 • C, 300 • C and 320 • C before the coating process (Figure 4). The mechanical profile did not vary according to the average arithmetic roughness, Ra, from 0.26 µm to 10 µm at 270 • C and 300 • C. Indeed, for all these materials, we notice a first maximal force peak (zone 1 represented by 1 in Figure 4) corresponding to the force needed to only take off a small upper part of the coating, with the lower part of the coating clinging to the copper substrate [20]. This first peak was followed by a second, sharper peak (zone 2) representing the folding of the unstuck upper part and a constant force area (zone 3) representing the simultaneous solicitation of the flexible coating and unfolding of the coating.…”

“…Copper specimens were preheated to 270, 300 and 320 • C to effectively melt the PA11 powder [23] and to assess the impact of the substrate temperature on coating properties. The time of immersion in the fluidized bed was chosen from the best process parameters found in our previous work of 6 s [20]. The coating length measured 20 mm.…”

“…We used a custom-made scraper to determine the adhesion strength at the interface between the coating and the copper substrate along the copper cylinder (Figure 3). More details on the mechanical test are given in our previous paper [20]. We performed tests on five replicate specimens of each material to ensure reliability.…”

“…The energy calibration of all spectra was accomplished using the binding energy of a carbon 1 s orbital at 285.0 eV. For details related to the mathematical fitting, please refer to our previous publication [20].…”

“…In our previous work dealing with a polyamide 11 coating on copper substrates processed with conventional fluidized bed coating, we observed that other parameters like preheating temperature and time of immersion in the fluidized bed could influence the coating properties [20]. It was observed that, even if increasing the copper preheating temperature promoted the aspect and thickened the coating, it undermined the interfacial adhesion.…”