Study And Preparation Of High Performance Polyimide Based Lubricating And Protectings Coatings

Organic bonded solid lubricating coating,one of the solid lubricating coatings,was used in military and other high-tech fields and civil and other technical fields because it's very superior wear and corrosion resistance.At the same time,because it could be applied to almost all of the parts in the project,the coating has a more wide range of application.In this paper,the polymer binder is polyimide resin(PI),the solid lubricant is polytetrafluoroethylene(PTFE),the functional filler is cadmium sulfide(CdS)and graphene oxide(GO).Meanwhile,we prepared two kins of solid lubricating coating,nano-cadmium sulfide filled with PI / PTFE composite resin and graphene enriched PI resin,and studied coating preparation process of the two bonding solid lubricating,bonding solid lubricating coating composition,the composition of the components,the composition of the components and the tribological properties and corrosion resistance of the bonded solid lubricating coatings.And we also systemically studied those items' effect of the properties of bonded solid lubricating coatings,which is the mixture ratio of the adhesives,solid lubricants and functional fillers,surface-modified nano-CdS particles and GO content and experimental conditions.And we also studied the friction and wear mechanism of nano-cadmium sulfide-filled PI/PTFE composite coatings,and further explored the friction and wear mechanism and corrosion resistance mechanism of the graphene-enriched PI coating.The specific conclusions are as follows:1.In this paper,the surface-modified CdS nanoparticles,N,N-dioctethyldithiocarbamate as the surface modifierthe,were prepared by liquid-phase precipitation using.The results showed that the prepared surface-modified CdS nanoparticles have a more uniform size,and there was also a good dispersion in the solvent.2.The effect and mechanism of the surface modified CdS nanoparticles as the functional packing of PI/PTFE composite lubricating coating on the friction and wear properties were investigated systematically.The results showed that nano-cadmium sulfide could reinforce the strength of PI/PTFE composites,so the surface modified CdS nanoparticles as PI/PTFE composite lubricating coating has excellent anti-friction and anti-wear properties.Under dry friction,the coating has the best antiwear.When the surface modification of CdS nanoparticles is 5% and the load is 200 N at 2.56 m/s.However,compared with the oil lubrication,because there was a protective layer of protective film between the coating and the friction,the coating has better friction and wear properties.3.Surface modification GO was prepared by liquid phase precipitation method using siloxane KH570 as surface modifier.The number of GO-peeled layers of the prepared surface modified was less,and the post-agglomeration of the modified GO was well improved.4.The friction and wear properties and corrosion resistance of the grained graphene and the modified graphene modified with KH570 as the functional filler of the polyimide coating were investigated.The mechanism was also studied,the results showed that: the mechanical properties of the coating could be improved by adding the graphene oxide and modified graphene,so the friction and wear properties of the coatings is better than the pure resin coating.And better than the use of KH570 on the modified graphene oxide,which led to the modified oxide graphene and resin bonding more closely,so the friction and wear performance,the addition of modified graphene coating,is better than the addition of oxidation Graphene coating.Because of their own conductive properties of the graphene oxide and modified graphene,this would inhibit the chloride ions infiltrating into the coating in the salt spray test,thereby enhancing the corrosion resistance of the coating.Therefore,when adding the graphene oxide and the modified graphene oxide into the coating,the salt spray resistance of the coating would be improved.At the same time,the coating would be more dense and uniform,bacause that the combination of the modified graphene and the PI resin was more closely.So compared with the coating added with graphene oxide,the salt spray time of the coating added with modified graphene was higher about twice.