Design of “double layer” texture to obtain superhydrophobic and high wear-resistant PTFE coatings on the surface of Al2O3/Ni layered ceramics

Solid lubricating polytetrafluoroethylene (PTFE) coating was designed to have a “double layer” texture after being sprayed on the untextured and textured surface of Al2O3/Ni layered ceramics. Surface texture of PTFE coating with smaller diameter and higher density showed excellent superhydrophobicity. Laser caused defluorinated and enhanced hardness of the PTFE coating. Meanwhile, Solid lubricants embedded in micro-dimples of substrate surface act as “mechanical self-locking” roles, which increase the surface contact area and provided a secondary lubricating effect, thus significantly increase the wear life of the coatings. Contact angle and wear life of the optimized "double layer" texture PTFE coatings could reach 160° and 1.6 × 104 s, which are about 2.0 and 5.0 times higher comparing to untextured smooth PTFE coatings surface, respectively.