Preparation Of Carbon Nanotube Reinforced Copper Matrix Composites By Spray Pyrolysis And Study Of Their Sintering Propertie

Cu and its alloys possess so many excellent properties,like good building ability,good corrosion resistance,high electricity and thermal conductivity,and are widely applied in many areas like transportation,metallurgy,mechanics,chemistry.But Cu is restrained in its applications due to its poor mechanical properties.Hence,it is necessary for us to add the second phase to the Cu base to improve its Cu mechanical properties.CNT is a reinforced phase with a unique atomatic structure,and is possessed with good electrical conductivity,thermal conductivity,mechanical properties.Adding CNTs to the Cu matrix can effectively improve the strength and hardness of the composite,and make the composite serve a better role in life.But the CNTs tend to form clusters in the composite material due to the large draw ratio,and the wettability and combination between the CNTs and Cu are bad,which will greatly affect the reinforcement of the CNTs on the compo site material and even result in the worse properties of the composite material than the pure Cu.The CNTs/Cu composite fabricated with powder metallurgy is fabricated through the pressing and sintering of the CNTs/Cu composite powder,the dispersion of CNTs and combination between CNTs and Cu in the CNTs/Cu composite powder will finally affect the properties,especially the mechanical properties,in the CNTs/Cu composite.So,the fabrication of CNTs/Cu composite with excellent properties rely on the fabrication of CNTs/Cu composite powder with CNTs that disperse uniformly and combine well with the Cu.Spray pyrolysis(SP)is a novel technique of fabricating powder which combines the advantages of gas phase method and liquid phase method.Its theory is that solution of precursor is atomized into the furnace by the atomizer and the reaction in the furnace is carried on by droplets,finally the Particles form with droplets and are sent into the collector.In this essay,CNTs were purified with SP,CNTs/Cu2O、CNTs/Cu2O-CuO and CNTs/Cu composite powder were fabricated with SP,CNTs/Cu composite is fabricated with the sPark plasma sintering and its sintering technique is investigated,then the following conclusions are drawn:The CNTs can be effectively purified by the SP,most of the amorphous carbons in the CNTs are eliminated after the SP,and the graphitization degree of the CNTs is improved;the best temperature for SP is 500℃;the SP process is easier to control and causes less damage on CNTs compared with the traditional purification technique;the CNTs/Cu2O-CuO composite powder which contains 30.0wt%of the CNTs possesses the best photocatalytic property and the degradation rate reaches 100%at 2h;in the CNTs/Cu composite powder which contains 50.0wt%of the CNTs,the combination between CNTs and Cu particles is the best;according to the results of the test of the mechanical properties,all the CNTs/Cu composite materials’ mechanical properties are better than pure Cu;the CNTs/Cu composite material which contains 0.5wt%of the CNTs possesses the best mechanical properties,whose tensile strength is 232MPa,yield strength is 146MPa,section shrinkage rate is 26.7%,fracture elongation rate is 11.1%.