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The pore diameter and porosity of SiC-DPF has been increased by elaborating its porous structure. Increasing the porosity of DPF decreases its strength and thermal conductivity. It was clarified how these characteristics affect the performance such as filtration characteristics, low pressure loss, maximum soot loading limit, and thermal response characteristics required for DPF. It was found that the basic characteristics of SiC such as high strength and high thermal conductivity play an important role in its high porosity.

SiC has very high thermal conductivity and mechanical strength. The cracking problem during regeneration could be successfully handled by using split-type DPFs that consist of multiple filter segments. For enhancing further durability of SiC-DPF, increasing the regeneration limit was successful by means of increasing a volume of the neck area located between SiC particles. The improvement was probably due to the lowering of Young's modulus and increasing of the thermal shock fracture resistance parameter R', which were results of increasing the neck volume and controlling the sintering method. Crack propagation mode changed from the conventional mode, and the cracks propagating throughout the whole tended to be restrained.

SiC is well known as a ceramic with high mechanical strength and thermal conductivity, and the R-SiC-DPF (recrystallized SiC-DPF) used these excellent properties is widely recognized as the substrate material for DPF. DPF system requires the material possessing high thermal shock resistance against an unexpected accident, such as an uncontrolled regeneration. One of the indices indicating the thermal shock resistance of the DPF is soot mass limit, which is an important factor determining the penalty of vehicle fuel consumption. In order to further increase the soot mass limits of R-SiC-DPF, this paper covers the attempts of IBIDEN to promote the sintering of the neck part of a SiC porous body using a sintering additive. Al2O3, well known as a sintering additive for a SiC dense body, was selected as the sintering additive.