Preparation And Properties Of Copper Matrix Composites Reinforced By ZnO And CNTs

Copper have been widely applied in artificial intelligence,high-end manufacturing,aerospace and other industrial fields due to its excellent properties in electric conduction,heat conduction and corrosion resistance.Unfortunately,the low strength at room temperature,poor mechanical properties and easily deformed at high temperature limit its further applications.In order to make copper not only possess excellent thermal conductivity and electrical conductivity,but also possess a series of excellent properties such as strong hardness,high wear resistance,and good workability,it is imperative to study new copper matrix composites.In this thesis,coprecipitation-powder metallurgy was adopted to prepare Copper matrix composites with ZnO and CNTs were chosen as Reinforcement,respectively.The Copper matrix composites,as well as composite powders,were investigated by scanning electron microscopy with energy dispersive X-ray analysis(SEM-EDS),X-ray diffraction(XRD).Archimedes drainage method,micro Vickers hardness tester,friction and wear tester,electrochemical workstation and static corrosion weightlessness test were utilized to evaluate the properties of prepared materials.The effects of reinforcement and its content on the microstructures and properties of the composites were investigated.The following conclusions were drawn from the analysis of the data:(1)ZnO reinforced copper matrix composites were obtained by using coprecipitationpowder metallurgy method in which ZnO is uniformly distributed in the form of hexagonal nanosheets.The highest Vickers hardness of ZnO-Cu composites can reach 119.44 HV,and the lowest wear rate is only 0.6%of pure copper.Meanwhile,the relative density and conductivity decreased less.The relative densities of the composites with ZnO content of 4wt.%and 8wt.%can be higher than 96%,and the conductivity was higher than 70%IACS.Unfortunately,the addition of ZnO reduce the corrosion resistance of copper matrix and the corrosion loss of 20wt.%ZnO-Cu is nearly three times than that of pure copper.(2)CNTs reinforced copper matrix composites were obtained by using coprecipitationpowder metallurgy method.The wettability of CNTs and copper matrix is much better after process improvement,but the relative density and conductivity of CNTs reinforced copper matrix composites decreased obviously,When the CNTs content is 4wt.%,the relative density is only 88.3%,and the conductivity is only 16.38%IACS.Even so,the CNTs-Cu composites exhibited excellent performance in Vickers hardness test and wear test with Vickers hardness value is up to 94.3HV and the best wear loss is only 0.8%of pure copper,respectively.More encouragingly,the corrosion resistance of copper matrix is greatly improved with the addition of CNTs.The corrosion weight loss of all composites containing CNTs is less than 30%of that of pure copper.