First-principles Study On The Preparation Of Silicon Carbide Porous Ceramic Supports And Their Mechanical Properties

Silicon carbide porous ceramic material has unique properties such as low thermal conductivity,low density,high specific strength,high thermal shock resistance,good chemical stability,high fluid permeability and good corrosion resistance.Therefore,it is used as the main material in high-temperature filtration and dust removal system.In order to overcome the inherent brittleness of ceramic materials,I strive to improve the mechanical properties and porosity of ceramic materials.In the first part of this study,some factors affecting the microstructure,flexural strength and filtration performance of silicon carbide porous ceramics are explored.Taking silicon carbide particles as the main raw material,I first explored the optimal sintering temperature and binder content,and then doped potassium carbonate into the binder to obtain the optimal doping content of potassium carbonate.On this basis,I explored the influence of pressure on porous ceramics.It can be obtained that the optimum sintering temperature is 1300?,and the optimum binder content is 10%.On this basis,the optimum doping content of potassium carbonate in the binder is 15%.At this time,the bending strength of the sample is 35MPa and the porosity is 24%.The best pressure for strip making is 5MPa,the maximum bending strength of the sample is 47MPa,the best pressure for film making is 9MPa,and the maximum porosity of the sample is29%.The second part is to use the Materials Studio to build the supercell model in the forcite module.Taking the experiment of doping potassium carbonate into the binder and changing the pressure as examples,this paper explores the first principle of the mechanical properties of the prepared porous silicon ceramics,and tries to explain the experimental data through the first principle.It can be obtained that with the increase of potassium oxide doping content,the ratio of binding energy is also gradually increasing,and the supercells are also combined more closely,that means the energy required for the overall dispersion of supercells into various parts will be more.This is consistent with the experimental conclusion that the flexural strength is also increasing with the K₂CO₃content in the binder gradually increasing from 0 to 10%wt.As the pressure increases,the binding energy of the supercell increases gradually with the increase of pressure,that means with the increase of pressure,the supercells bind more closely,and more energy is required to disperse the whole supercell into various parts.This is consistent with the previous experimental results that the bending strength of the sample increases with the increase of pressure.