Magnetron Sputtering Based Carbon Fiber Modification And Its Composite Material Preparation

Carbon fiber is an important raw material for composite reinforcement,but the surface energy of carbon fiber is low due to the preparation process and defects of the original filament,and there are internal holes and surface grooves,which not only restrict the tensile strength of carbon fiber,but also affect the interfacial bonding ability between carbon fiber and resin matrix,so that the mechanical properties and applications of carbon fiber composites are greatly affected.In order to enhance the mechanical properties of carbon fibers and their composites,surface modification of carbon fibers is required.In this work,we will start from the interfacial microstructure of carbon fibers and their composites,and use the simple,environmentally friendly and efficient magnetron sputtering technology as a modification tool to deposit film structures with nanometer size on the surface of carbon fibers.The effect of magnetron sputtering on the mechanical properties of carbon fiber composites will be analyzed by combining the transition mechanism of the interfacial layer and the "external toughening" mechanism of the composite material with the modification of the carbon fiber surface by magnetron sputtering.The details of the study are as follows:(1)Firstly,magnetron sputtering time was used as the modification process parameter,then carbon target primary sputtering and carbon/tantalum secondary sputtering were used as the modification means,and scanning electron microscopy,X-ray diffractometer analysis,X-ray photoelectron spectroscopy,atomic force microscopy,surface/interface tension analyzer and electron peeling machine were used to characterize the deposited film on the carbon fiber surface under different modification conditions,and analyze the effect of magnetron sputtering process(time)and The effects of different magnetron sputtering methods(secondary sputtering)on the structure and properties of the deposited films were analyzed.The results show that the magnetron sputtering process and the magnetron sputtering method affect the structure and properties of the deposited films.When primary sputtering with carbon as the target material is used as the modification means,it is found that different magnetron sputtering times affect the morphology and structure of the deposited films,but do not affect the physical and chemical composition of carbon fibers,and the film thickness increases with the increase of magnetron sputtering time,and the denseness of the film is improved.The surface roughness of carbon fibers modified by magnetron sputtering gradually increased with the increase of magnetron sputtering time,and the surface energy was also effectively improved.Among them,the surface energy of the carbon fiber modified by 30 min sputtering time increased the most,by 34.65%.The adhesion strength between carbon film and carbon fiber increased with the increase of magnetron sputtering time,and the bonding strength was the largest when the sputtering time was 50 min,which was 3.09 N.The surface roughness of carbon fiber was 13.6 nm after carbon/tantalum secondary sputtering,which increased 27.1% and 20.35% compared with the average surface roughness of unmodified and carbon coated by primary sputtering for 30 min,respectively,and the surface energy The surface energy increased by 38.25% compared with that of unmodified carbon fiber,and the adhesion strength increased by 76.15% and 38.63%compared with that of unmodified carbon fiber and after 30 min of primary sputtering,respectively.(2)The mechanical properties of carbon fibers modified by primary sputtering were improved,and the tensile breaking strength and strength of carbon fibers were increased,and the tensile breaking work was also enhanced.Among them,the tensile breaking strength of carbon fiber monofilaments after 30 min modification treatment increased the most,which was 6.27% more than that of unmodified carbon fiber monofilaments.The tensile breaking work of carbon fiber monofilaments modified by 50 min was the largest,which increased by 19.73%compared with that of unmodified carbon fiber monofilaments.At the same time,the tensile breaking strength of carbon fiber bundles modified by one magnetron sputtering was also enhanced,and the tensile breaking strength of carbon fiber bundles modified by 30 min was the largest,which increased by 6.9% compared with unmodified.After two magnetron sputtering of carbon/tantalum,the tensile fracture strength of carbon fiber monofilaments was slightly smaller than that of unmodified carbon fiber,and the tensile fracture strength of carbon fiber bundles was slightly smaller than that of carbon sputtering,which was 6.3% higher than that of unmodified carbon fiber bundles,and the tensile fracture strength was basically the same as that of unmodified carbon fiber bundles.(3)The mechanical properties of carbon fiber epoxy(CFEP)composites before and after modification were tested and characterized to analyze the effects of magnetron sputtering modification means and magnetron sputtering process on the mechanical properties of carbon fiber composites.The results showed that the in-plane shear strength,tensile strength and bending strength of the modified CFEP were improved compared with the unmodified CFEP.The in-plane shear strength,tensile strength and bending strength of CFEP modified by 30 min were increased by 39.02%,22.20% and 28.62%,respectively,compared with the unmodified CFEP when carbon target magnetron sputtering was used as the modification method.The in-plane shear strength,tensile strength and bending strength of CFEP modified with carbon/tantalum twice by magnetron sputtering increased by 63.53%,20.82% and 33.15%,respectively,compared with the unmodified CFEP.