Study On The Selective Laser Melting And The CVD Growth Of Graphene Of Metal Cellular Lattice Structures

Graphene is a quasi-two-dimensional material with only one carbon atom layer.This special structure makes it have excellent mechanical,electrical and optical properties.Graphene also has a specific surface area much larger than that of general materials,so it has a wide range of applications in the fields of catalysis,energy,and photovoltaic devices.But as a two-dimensional material,graphene has outstanding anisotropy,and the use of existing graphene materials is usually in the shape of powder materials,the distribution and orientation of graphene sheets are randomly arranged,and graphite sheets is prone to agglomeration,which greatly limits the excellent performance of graphene.Therefore,the preparation of three-dimensional(3D)graphene has been proposed.Currently,chemical vapor deposition(CVD)is the main method for preparing 3D graphene.Among them,the porous metal template used in the CVD method is the main factor that determines the structure and performance of the prepared graphene.The porous metal template formed by the traditional method has a random pore structure,resulting in uncontrollable structure and performance of the prepared 3D graphene material.To this end,this paper proposes the use of laser selective melting(SLM)additive manufacturing technology to form a metal grid structure as a template for the CVD method,and finally produce a controllable 3D graphene.The specific research results are as follows:Firstly,the fabrication of Mn70Ni30 alloy cellular lattice structure by SLM was studied.It was found that the surface of the formed sample was rough and adhered to the incompletely melted metal powder.At the same time,there was a step effect,and its generation mechanism and optimization method were analyzed.The mechanical properties of the Mn70Ni30 alloy cellular lattice structure formed by SLM are characterized.Its compression modulus and yield strength meet the prediction of the porous structure by the Gibson-Ashby model.The Mn in the Mn70Ni30 alloy is removed by chemical corrosion to prepare porous Ni for CVD Graphene was grown by the method,the influence of different corrosive liquids and corrosion parameters on the corrosion effect of Mn70Ni30 was studied,and CVD method was used to grow graphene on the prepared porous Ni template.Secondly,a Ni75Cu25 alloy grid was formed by SLM technology as a CVD method for growing graphene templates.The morphology and structure of graphene grown on the Ni75Cu25 alloy template by CVD at different temperatures were studied.The results showed that the higher the reaction temperature,The layer number and layer thickness of the graphene to be grown will be smaller.When the temperature exceeds 1150 ° C,graphene cannot be formed on the template surface.This is because the increase in temperature makes the solubility of C atoms formed by the cracking of CH4 in Ni75Cu25 alloy increase sharply,which inhibits the formation of graphene.The performance of the Ni75Cu25 alloy grid composite graphene material prepared was characterized and analyzed.Compared with the Ni75Cu25 grid structure without graphene growth,the thermal diffusion coefficient of the graphene composite material has also been greatly improved,at 100 Under the condition of ?,the thermal diffusion coefficient of Ni75Cu25 alloy grid composite graphene material increased by 12.5%.This is due to the high thermal conductivity of graphene,which increases the thermal conductivity of the composite grid material.This paper proposes a new idea of using SLM technology combined with CVD method to prepare 3D graphene,and effectively solves the problem of uncontrollable structure and performance of the metal grid prepared by the traditional process and the graphene grown on the surface.It lays the foundation for the preparation of 3D graphene and its composite materials with controllable structure and properties.