Study On Preparation Of Cf/Cu Composites By Hot Pressing Sintering

Carbon fiber reinforcing copper matrix composites,usually donated as Cf/Cu,are composed of copper matrix and enhance body carbon fiber.As the name implies,this type of composite material not only possesses the conductive and easy processing properties of metallic copper,but also inherits the characteristics of high specific strength and modulus of carbon fiber,especially its excellent high-temperature thermal stability,which is suitable as a substitute material for many products.In this paper,carbon fiber was pretreated by different methods such as cauterization,acetone,nitric acid,and nitric acid and ultrasonic synergistic effect.The optimized pretreatment process was selected by investigating the effect of pretreatment on carbon fiber modification.The optimal copper plating bath formulation and thermal reduction process parameters are obtained by designing the orthogonal experiments on solution and thermal reduction process.And explore the growth mechanism of crystal grains in the thermal reduction process.Finally,by designing the orthogonal test on the hot-press sintering process,the effect of different sintering processes on the physical properties of Cf/Cu composites was investigated to determine the optimal hot-press sintering process.The research content and main conclusions of this article are as follows:?1?Carbon fiber surface pretreatment is performed by means of burning,acetone,nitric acid,and nitric acid in combination with ultrasound to analyze the effect of different modification methods on the surface morphology and weight loss of carbon fiber,and to explore the modification principles of various methods.The results show that the fiber pretreatment has a great influence on the copper plating effect.According to the characteristics of the preferred nucleation effect,the grain growth is preferentially performed in the area where the surface activity of the fiber is strong,while the combination of burning combined nitric acid and ultrasonic is effective.The treatment method has the most excellent effect on the surface modification of carbon fiber.The main manifestation is that the treated carbon fiber not only shows a dispersive improvement,but also a bundle-like agglomeration phenomenon.After the thermal reduction,the copper coating on the surface is the most ideal.?2?By designing the orthogonal experiment of the copper plating bath,the influence of the content of the bath components on the copper plating effect is explored.The results of the study showed that the concentration of polyvinyl alcohol played a major role,while sodium SDBS followed and glycerol was the smallest.The main salt CuSO₄·5H₂O concentration is still the main factor influencing the effect of the bath.The addition of starch can effectively improve the bath effect.In this paper,the optimal copper plating bath formulation was determined as follows:the amount of polyvinyl alcohol was 1%,the amount of sodium SDBS was 4 g/m L,and the amount of glycerol was 7%.?3?Coated copper carbon fiber with a uniform surface deposition layer was prepared by a high-temperature thermal reduction method.The optimum thermal reduction process parameters were explored by designing related orthogonal experiments,and the coating materials were investigated using XRD,SEM,and TG analysis methods.Phase and surface morphology,and then analyze the growth mechanism of the surface coating in high temperature,hydrogen atmosphere.The results show that the reduction temperature and the redox reaction of Cu²⁺in the copper salt coating on the surface of hydrogen and carbon fiber are the core driving force for the growth of the sediment layer.However,prolonging the holding time only provides sufficient growth cycle for the copper coating.The optimal thermal reduction process conditions were determined as follows:thermal reduction temperature was 900?,holding time was 90 min,and protective atmosphere H₂:N₂?V%?was 1:1.?4?To investigate the oxidation resistance of copper-plated fibers under high temperature conditions,the mechanism of the improvement of the oxidation resistance of the copper-plated fibers was investigated through SEM micrographs and the weight loss rate.The results show that the weight loss of copper-plated fibers is significantly reduced compared to un-plated carbon fibers,and the overall weight loss rate is evenly increased.This phenomenon indicates that surface metallization of carbon fibers can be used as an effective method to improve the oxidation resistance of carbon fibers way.?5?Using vacuum hot-pressing sintering to prepare composites,through the design of related orthogonal experiments,to explore the best hot-pressing sintering process parameters,and to use SEM,resistivity and instantaneous thermal expansion coefficient data to explore the process parameters and the physical properties of composite materials the relationship between,determine the optimal hot-press sintering process parameters.The results show that the content ratio of Cf and Cu,the hot-pressing temperature,the hot-pressing pressure and the holding time all have a significant effect on the physical properties of the composite.In this paper,the optimal hot-press sintering process parameters are determined as follows:sintering temperature is 850?,hot-pressing pressure is 15 MPa,and hot-pressing time is 50 min.