等离子喷涂Al2O3-40%TiO2强化聚四氟乙烯不粘涂层的制备及其性能研究OA

Polytetrafluoroethylene(PTFE)-based non-stick coatings are widely used in cookware,however,they suffer from poor wear resistance and a rapid decline in hydrophobicity upon surface wear.In the present work,a novel structural design in which the PTFE coating is reinforced with discrete Al2O3-40%TiO2(AT40)ceramic protrusions is proposed to improve the wear resistance.During friction,the high-hardness ceramic protrusions support the friction counterpart to prevent rapid wear loss of the PTFE and thereby enhancing the wear resistance of the non-stick coating and improving durable non-stick performance.Firstly,a dense AT40 coating is prepared on the 304SS substrate surface in order to improve the corrosion resistance of the composite coating with the roughness of Ra 6.5 μm.Secondly,semi-molten AT40 particles are deposited via plasma spraying to prepare an AT40 ceramic coating of high surface roughness with numerous AT40 mounds on the surface.Subsequently,PTFE is used to fill the gaps between the semi-molten AT40 particle mounds to form a composite coating.The influence of spraying distance on the surface structure of the AT40 coating is investigated,and the mechanism how the surface roughness of the AT40 coating affects the wear resistance and long-term non-stick performance of the composite coating is elucidated.Additionally,characterization of the AT40 coating surface morphology and roughness is performed with a laser confocal microscope and the cross-sectional microstructure and surface morphology of the composite coating are characterized by scanning electron microscopy.The porosity of the dense coating is quantified using image analysis.The durable non-stick property of the composite coating is characterized by evaluating both wear resistance and variations in water contact angle(WCA)before and after abrasion.Wear mechanism and surface structure evolution of the composite coating during the wear process are also investigated. Results show that the bilayer AT40/PTFE composite coating with high roughness can be fabricated through hybrid plasma spraying and PTFE deposition.Under optimized parameters,the coating exhibits excellent interfacial bonding and defect-free internal structure without micro cracks or delamination.As the spraying distance increases from 40 mm to 80 mm,120 mm,and 150 mm,the surface roughness of the plasma-sprayed AT40 ceramic coating initially decreases and then increases,which is highly dependent on the molten-state and impact velocity of the AT40 particles.At a spraying distance of 40 mm,the roughness reaches its maximum value at Ra 19.3 μm and Rz 220.4 μm.Wear resistance of monolithic PTFE coating versus AT40/PTFE bilayer coating is comparatively investigated through ball-on-disk tribological testing,the monolithic PTFE coating directly applied on grit-blasted 304SS exhibits a rapid friction coefficient surge from 0.20 to approximately 0.65 after only 5 000 cycles,indicating complete coating depletion.In contrast,the optimized AT40/PTFE bilayers sprayed in the distance of 40mm maintains a stable and low friction coefficient(below 0.5)even after only 25 000 cycles.Furthermore,wettability tests reveal that for the optimized AT40/PTFE composite coating,the water contact angle(WCA)only decreases from 133 o to 101o even after 25 000 cycles of standard friction while the contact angle of the conventional glass micro-ball reinforced PTFE decreases from 118o to 45o only after 5 000 cycles.This validates that the AT40/PTFE composite coating possesses significantly enhanced durable non-stick performance,offering a service life more than five times longer than that of the monolithic PTFE coating.