Formation Mechanism and Properties of Porous Structure of Cordierite in Talc/Kaolin System

Diesel particulate traps can be used to intercept pollutant particles in flue gas and this interception effect is closely related to the pore size distribution and porosity of the ceramic matrix. Effectively managing the porous structure of cordierite ceramics is crucial for optimizing their DPF filtration efficiency. The impact of talc/kaolin mass ratios on the porous structure of cordierite was studied, elucidating the pore formation mechanism and evolution within the cordierite matrix. The decomposition process of talc, coupled with volume shrinkage during crystallization, serves as the foundation for pore formation in the cordierite matrix. Through liquid-phase sintering, the gaps between the laminated flake powders began to merge, forming a diffuse distribution of small holes. Then, the small pores were connected to form linear pores, which eventually merged into large pores with smooth edges. Simultaneously, the effects of talc/kaolin mass ratios on the thermal conductivity, shrinkage, and three-point bending strength of cordierite porous ceramics were explored. The 0.1TKMS exhibited optimal performances, with a value pore size of 0.15 μm and a porosity of 18.41%. The optimized sample had a thermal conductivity of 2.06 W·m^-1·K^-1 and a three-point bending strength of as high as 51.83 MPa. The thermal conductivity was increased by 63.5%, the maximum volume shrinkage rate was decreased by 83.9% and the maximum three-point bending strength was increased by 239.2%.