International. In a recently published study, Chinese scientists investigated the hydrophobic and wear-resistant properties of PTFE/CF composite coatings, to correct the phenomenon of embolization in bits.
This phenomenon usually occurs in the process of oil exploitation using a polycrystalline diamond bit (PDC). By using carbon fiber (CF) reinforced polytetrafluoroethylene (PTFE) composite coatings applied to PDC bits, friction and wear properties and hydrophobicity would improve.
In the aforementioned study, a particular process was used to prepare COATINGS composed of PTFE/CF with different CF contents. The mass fractions of CF in PTFE are 10%, 15% and 20%, respectively. The results showed that when the mass fraction of CF is 20%, the coefficient of friction is 0.17 ± 0.01, which does not represent a significant increase, while the wear rate is 2.74 × 10−4 mm3 / Nm, which is the lowest of all and is reduced by about 29.7%, compared to that of pure PTFE.
In turn, the WCA composite coating of PTFE /20% CF increases to 122.0° ± 2.0°, which shows good hydrophobicity, while the WCA of pure PTFE coating is only 106.3° ± 1.5°. Abrasive wear and adhesive wear are the main wear mechanism of composite coatings under air exposure conditions.
The surface morphology of the coatings was observed by scanning electron microscope (SEM) and 3D measuring laser microscope, and water contact angles (WCA) were measured.
Source: European Coatings.
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