| Mild steel with superior performance in strength,malleability and formability,have an abundant resource,mature metallurgical process as well as lower cost.It has been widly developed and plays an enormously valuable role in both daily life and industry.However,due to its disadvantage of surface performance,the mild steel have an unsatisfactory lifespan,which subsequently restrict its practical application.For instance,mild steel with a high surface energy shows a strong adhesive force with water.So once applied in hydraulic transport or vessel fabrication,there could be major energy loss.To solve this problem,we can improve the surface wettability of mild steel,by means of modifying with superhydrophobicity to reduce pressure drop and energy loss.On the other hand,we can also improve its self-cleaning property,aiming at using as the anticorrosion and antifouling material.Further more,by improving the solid tribological property of the mild steel joint and the bearing part,the usage amount of the lubricating oil could be reduced,the corrosion risk could be decreased,and the friction loss could be diminished.By the way,creatively fabricating a luminescent coating on the surface of mild steel to monitor the health of substrate,could be timely and effectively for predicting mechanical damage.Thus,in this thesis,we electroplated the functional nickel besed nanocomposite coatings on the surface of mild steel by one-step electroplating method.And found that the hydrophobic,corrosion resistance,self-cleaning property,hardness and wear resistance of the substrate were improved,as well as endowed the integrity of luminescence using in on-line and in-situ monitoring of coating.In the experimental part,the preparation methods,influencing factors and performance analysis of three nanoparticles doped nickel coating were mainly introduced,the three composite coatings are Ni-tungsten disulphide nanoparticles,nickel-phosphorus-molybdenum disulphide nanoparticles and nickel-phosphorus-luminescent particles.In addition,in terms of the source of technique,the application of nanoparticles modification has been extended.Based on the property of silver nanoparticles,we synthesized a couple of polymer – siver nanoparticles.The main work are as follows:1.The fabrication of nickel-tungsten disulphide nanoparticles superhydro-The as-prepared metal-ceramic superhydrophobic coating avoided the modification of low surface energy organics.By well-designed experiments we studied the influence of the current density,the concentration of tungsten disulphide nanoparticles and the saccharin concentration on the surface morphology,wettability,chemical composition of the coating.The static contact angle between the coating and water is 158.3 degree,and the dynamic rolling angle is 7.7 degree.The corrosion resistance of the coating was studied by dynamic potential polarization curves(Tafel curves)and impedance spectrum(EIS),the lowest corrosion current density was 2.07 × 10-7 A / cm2,which greatly improved the corrosion resistance compared with 1.21 × 10-5 cm2 of naked mild steel.The crystal structure of the coating was analyzed by means of Xray diffraction,and the deposition rate of tungsten sulfide nanoparticles on the surface was measured by EDS.The relationship between the tungsten sulfide content and the hydrophobicity and corrosion resistance of the coating was established.In addition,the coating also showed anti-abrasion property,low water adhesion and self-cleaning property.2.The fabrication of nickel-molybdenum disulphide nanoparticles wear-resistant composite coating.In the process of preparation,ultrasonic assisted electrochemical deposition technology was introduced.The usage of ultrasonic can effectively prevent the dendrite growth effect of molybdenum disulphide,and get coating with smaller grains and smooth surface,which make higher microhardness and wear resistance.It is found that the usage of surfactant and ultrasonic,concentration of molybdenum disulfide nanoparticles have influence on the surface morphology and chemical composition of coating,thus affecting its hardness and friction performance.The dry friction coefficient of samples prepared with and without ultrasonic were 0.11 and 0.08 respectively,while the dry friction coefficient of mild steel is as high as 0.7.The hardness and wear loss of the coating were analyzed by Vivtorinox micro hardness tester and 3D profile instrument.The wear loss mechanism of the coating was studied by a large number of SEM analysis.3.The fabrication of nickel-luminescent nanoparticles composite coating.The BaMgAl11O17:Eu2+ blue luminescent particles were introduced as the doped powder,cetyltrimethylammoniumbromide(CTAB)and polyethylene glycol(PEG)were mixed in the bath as the surfactant.Nickel-phosphorus layer embedded with luminescent particles were deposited on the surface of mild steel substrate by phobic composite coating.electroplating.The luminescent property of as-prepared coatings was monitored by an ultraviolet lamp with wave length of 365 nm.The surface morphology and elements composition of coatings were analysed by scanning electron microscope and energy disperse spectroscopy,respectively.The results showed luminescent particles content in coatings were influenced by the concentration of surfactant,thus the coatings exhibited distinguishing intensity of luminescent effects.In particularly,combinated addition of CTAB and PEG could be more efficient in the deposition of luminescent particles than others.Moreover,intense luminescence could be acquired on the coating fabricated by the system with low stirring agitation.4.The fabrication of polyvinyl alcohol – silver nanoparticles,poly 2-aminothiophenol – silver nanoparticles anti-bacterial composite material.The nanoparticles have excellent effect on the functionalization and modification of material,based on this theory,the application of nanoparticles has been extended in this study.A couple of polymeric hybrid materials modified by nanoparticles were fabricated,including polyvinyl alcohol and poly 2-aminothiophenol.The structure of hybrid materials were characterized by uv-vis,FTIR,XRD and TEM.The results showed that both of the two materials acquired excellent antibacterial property.The five kinds of as-prepared nanocopsites all acquired various properties.The fabrication methods were simple and efficient,particularly for the single step preparation method which have a significant importance in the pratical production.These nanocomposites have potential applications in the corrosion protection,antifouling,antibacterial protection,loss monitoring of marine equipments and their improvement. |
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