Study On Processing And Electrical Properties Of Graphite/Alumina Based On Triply Periodic Minimal Surface Architectures

Carbon ceramic composite materials have both high strength,high chemical stability and high conductivity of carbon materials,and have broad application prospects in the blank areas where traditional metals and polymer materials such as oxidation resistance and corrosion resistance cannot be used.How to control the distribution of the functional phase on the ceramic matrix is the key and key point to ensure the performance of the composite material.In this paper,combining graphite 3D printing technology and ceramic gel injection molding process,through the precise design of graphite structure,it is possible to achieve the control of the performance of composite materials: First,optimize the design of graphite structure,the structure is based on the mathematically known three-period pole The small curved surface is characterized by zero average curvature and large specific surface area,which can effectively avoid the generation of concentrated stress,and can well meet the design requirements of this article.The preparation of the design character graphite skeleton,and then compounded with the ceramic slurry obtained by gel injection molding,and finally through an integrated drying and sintering to obtain a graphite / ceramic conductive composite material based on a minimally curved structure,and analyze the electrical properties and mechanics of the material Performance,provides a new idea for the development of high-performance graphite conductive materials.The research results are as follows:(1)With the premise of ensuring the electrical performance of the structure and reducing the amount of graphite,the finite element method was used to analyze the graphite structure based on different minimal surfaces(Gyriod,IWP,Diamond)and its different structural parameters(lattice period,increase Thickness)under the electrical performance.It is found that the graphite structure table based on the Gyriod surface junction selects the most excellent electrical properties,and when the volume fraction is fixed,the conductivity of the structure increases with the increase of the lattice period,which provides a suitable framework structure for later selection.For reference.(2)The graphite skeleton with extremely small curved surface features was successfully prepared by SLS technology,and the secondary curing,impregnating phenolic resin,carbonization,impregnating silica sol,high temperature sintering were determined for the sparse and porous interior of the newly printed skeleton and the poor performance.A series of post-processing strengthens the process route.The results show that the sample after strengthening treatment found that the resin filled the internal voids of the skeleton and then through high temperature graphitization,effectively promoted the density of the skeleton,thereby improving the conductivity,the density can reach 1.24 g / cm3,and the conductivity reaches 183.80S·cm-1.(3)With the goal of reducing the shrinkage of ceramics and ensuring the filling ability of the slurry,the preparation of low viscosity and high solid phase ceramic slurry in gel injection molding was studied.It was found that the dispersant selected sodium polyacrylate to be added in an amount of 1.2wt%,the stirring time was 1.5 ? 2h,and the viscosity was the lowest when the p H value was 9;the content of organic monomer was 12? 18wt%,organic monomer: crosslinking agent ? At 10 o'clock the gel properties are good.And explore the degassing method of the slurry and the influence of the initiator and catalyst on the curing time.(4)By impregnating the graphite skeleton with silica sol and then composite curing with ceramic slurry,whisker-like silicon carbide can be generated at the interface after high-temperature sintering in the later stage,which effectively improves the interface combination of the two phases.And explored different particle grading schemes,integrated freeze-drying and sintering processes to achieve the "net-shaped" preparation of graphite /ceramics with complex structure.When the content is unchanged,the more dispersed the distribution of the graphite skeleton,the better the conductivity and compressive strength of the material,which provides a basis for reducing the graphite content and improving the performance of the material.