Study On Preparation Of Polytetrafluoroethylene Functional Coatings On Carbon Steel Surfaces And Its Performance

Carbon steel plays an important role in daily life, industrial and agricultural manufacture, and national defense construction. The corrosion of carbon steel brings about damage in personal, collective, and national manufacture perspective. Surface coating protection is an effective way to slow down the air corrosion of carbon steel materials. Compare with other polymer materials, fluorine resins exhibit excellent chemical resistance, non-adhesive, low friction coefficient, high-temperature stability, and low-temperature tenacity behaviors, which play an important role in modern industrial development. Polytetrafluoroethylene (PTFE) leads the dominant role in fluorine resins, which is extensive used in fields including petroleum and chemical engineering industry, astronautics, electronics, architecture, textile and medicine.In chapter 1, basic properties and modification methods of PTFE were summarized. Filling and blending modification method used in this study were introduced.In chapter 2, the chemical reagents and experimental instruments used in this study, the preparation method for nanoparticle-filled (NP-filled) superhydrophobic PTFE coating and epoxy resin-filled anti-wear high-temperature endurable coating were summed up.In chapter 3, a comparative study on inorganic SiO2 and organic PTFE NPs in the preparation of superhydrophobic PTFE coating emulsion mixtures was implemented by physical blending. The raw SiO2 NP was modified by silane coupling agent KH-570 before adding. The hydrolysis time of KH-570, the time and temperature of modification was controlled during the process. The dispersion of NPs in PTFE coating emulsions was enhanced by magnetic and ultrasonic stir. The uniformity of coatings were further guaranteed by spraying process. Results show that SiO2-filled coating surfaces have maximum static contact angles (SCAs) of about 150°, while the maximum SCA of PTFE NP-filled coating surfaces is 163.1°. The H-SiO2-filled coating surfaces have better uniformity than R-SiO2, while the PTFE NP-filled coating surfaces display much denser structure than SiO2. All fabricated surfaces have good thermal stability and tolerate temperatures up to 550℃. Adhesion and hardness tests show that the prepared SiO2 and PTFE NP-filled coating surface have good anti-wear performance. The PTFE NP-filled coating surfaces exhibit excellent acid/alkali erosion and water immersion resistance.In chapter 4, the corrosion resistance ability of PTFE and anti-wear property of epoxy resin were combined for the preparation of anti-wear high-temperature endurable coating, solving the problem that epoxy resin does not resist water and PTFE wears out easily. Pencil hardness tests show that the hardness of fabricated coatings lie in the grade of above 6H. After curing and annealing, the coating surfaces look smooth and exhibit excellent acid/alkali erosion and water immersion resistance.