Nucleation behavior of CaCO₃ scale on the surface of PTFE/PPS composite coatings in geothermal water environments

The anti-scale performance of polytetrafluoroethylene (PTFE)/polyphenylene sulfide (PPS) composite coatings was studied by scanning electron microscopy (SEM) and energy dispersion spectrometry (EDS). The effect of the surface microstructure of PTFE/PPS coatings on the nucleation behavior of CaCO₃ scale was analyzed. The results indicate that the surface microstructure of PTFE (latex)-blended PPS composite coatings is poriferous, and PTFE asymmetrically distributes inside and outside holes on the coating surface, inducing CaCO₃ scale to nucleate firstly on the hole inside and wall. The contact angle of PTFE/PPS coatings decreases with prolonging immersion time. The increasing rate of scaling on PTFE/PPS coatings is obviously less than that of 304 stainless steel and PPS coatings.