The Process And Short Fiber Strengthening Mechanism Of The Interface Between Composite And Coating

The fiber reinforced plastic(FRP)composites have various advantages,such as high specific strength,high specific modulus,good fatigue-resistance and outstanding designability.The FRP composites with surface metallization not only can keep their excellent mechanical property,but also can obtain the characteristics of metal,such as outstanding conductivity,good wear-resistance and strong airtight property,which could extend the application field of FRP composites vastly.Compared to metal materials,the FRP composites are difficult to form uniform micro-surface by surface pre-treatment because of the characteristic of anisotropy and heterogeneous.The polarity of the metal coating and the FRP composites is quite different,which lead to weak performance of bonding interface between metal coating and composites.Therefore,it is a significant project to study the metalized composite process which could enhance the interfacial bonding strength between metal coating and FRP composite.This study is supported by “the Fundamental Research Funds for the Central Universities”(DUT15QY27).A new surface metallization process of FRP composites was proposed to enhance the interfacial bonding strength between metal coating and composite based on electroless plating process,the short fiber strengthening of interface and the contact moulding process of composites.The surface metallization process and the interface strengthening mechanism between metal coating and composite were also discussed.The main works are as follows:First,a layer containing short fiber with nickel plating was prepared.The FRP composites laminates were manufactured by contact moulding process.The layer was coated on the composite surface when the last layer of FRP composite was finished.The layer containing short nickel-plated fiber and composite laminates was co-cured at the same process condition.Second,a uniform Ni-P coating was successfully deposited on the FRP composite surface by electroless plating after appropriate mechanical roughening and acidification.Effects of electroless plating time,loadage and the surface roughness of composites on the coating morphology,coating thickness and deposition rate were systematically discussed.Finally,the tensile test method was used to test the interfacial bonding strength between nickel coating and composites.The influences of surface roughness of composite,the content of short nickel-plated fiber and the direction of short fiber on the coating bonding strength were investigated.The scanning electron microscope(SEM)and digital microscope with large depth-of-field were employed to observe the surface microstructure,cross-sectional micrograph and fracture surface of nickel coating.The strengthening mechanism of short nickel-plated fiber on the interfacial bonding strength is analyzed.