Preparation And Properties Of In-situ Graphene/Copper Composites Based On Carboxylic Acid

Graphene has become an ideal choice for copper matrix composite reinforcement because of its excellent mechanical and electrical properties.This project is based on the excellent performance and huge application potential of graphene copper-based composite materials.Graphene copper matrix composites using different types of carboxylic acid molecules as carbon sources were prepared in situ during the sintering of composite materials,characterized by X-ray diffraction,scanning electron microscope,transmission electron microscope,raman spectrometer,mechanical properties and electrical performance equipment.The influence of surface pretreatment process of copper powder carbon source content,carboxylic acid molecular types on the graphene morphology,composite structure and performance were studied.This project found that acetic acid as a reducing agent for copper powder can not meet the need for full deoxidation of copper powder.The treatment of acetic acid will change the copper oxide to cuprous oxide.With the increase of acetic acid content,cuprous oxide will further convert into copper acetate.Acetic acid as the carbon source during the sintering of composite materials can not be effectively converted into better quality graphene.But with the increase of acetic acid content,the skeleton structure of graphene is gradually obvious and the pore size is equivalent to the particle size of copper powder,confirming that the carbonization process mainly occurs on the surface of copper powder.The use of formic acid as a reducing agent for copper powder can fully reduce the original copper powder and improve the surface state of the copper powder,which basically does not affect the particle size of the copper powder.This process can effectively reduce the oxygen content in the composite material and improve the overall conductivity of composite materials.Graphene copper-based composite materials were successfully prepared using different types of carboxylic acid molecules as the carbon source.The characteristic peak of graphene with nonanoic acid and lauric acid as the carbon source indicates that the arrangement of the carboxylic acid molecule is more regular and more conducive to the formation of graphene as the number of carbon atoms increases in the carboxylic acid molecule.Hydrogen treatment of copper powder at 300? for 1h can fully activate the surface of the original copper powder without affecting the particle size of the copper powder.The surface of the copper powder is smoother and the catalytic activity is higher,which is conducive to the uniform coating of carboxylic acid molecules and the improvement of the electrical conductivity of composite materials.The D peak in the Raman test results of the composite corrosion products based on heptanoic acid and nonanoic acid almost disappeared,indicating that the carboxylic acid as the carbon source can be used to prepare the better quality in situ graphene after optimizing the experimental conditions.The graphene with better coating effect is directly observed from the H₂-C7-Cu composite structure and the graphene mainly exists at the grain boundary,which can comprehensively and uniformly coat the copper grains.By optimizing the preparation process of carboxylic acid-coated copper composite powder,the coating uniformity of carboxylic acid molecules is improved.Tensile strength elongation at break and the electrical conductivity of H₂-C7-Cu reached 268 Mpa,22.1%,and 91.2% IACS,respectively,and the overall performance of the composite material has been significantly improved.