Assertion: cordierite's resistance | /r/HasProperty | improved
Facets:
value: by increasing the pore volume
type: MANNER
Source sentences:
text: Moreover, the present invention is based on the discovery that by selecting a chemical composition of 42-52% by weight of silica, 34-48% by weight of alumina and 10-18% by weight of magnesia, preferably 44-51% by weight of silica, 35-45% by weight of alumina and 11-16% by weight of magnesia, a ceramic honeycomb consisting mainly of cordierite in the crystal phase and containing not more than 35% by weight, preferably not more than 30% by weight, more preferably 1-25% by weight of at least one crystal selected from the group consisting of spinel, sapphirine, mullite and corundum can be obtained and is higher in the softening and fusing temperatures than the ceramic honeycomb consisting of cordierite alone and slow in gradient of softening shrinkage curve from the softening temperature to the fusing temperature and the thermal resistance is improved, further that the ceramic honeycomb has substantially no difference in the thermal expansion coefficient from the ceramic honeycomb consisting of cordierite alone and is high in the thermal shock resistance.
text: Further, it has been found out that the adhering ability, catalytic activity and resistance to catalyst poison are closely related to the pore structure of the ceramic honeycomb catalyst substrate, i.e. the catalytic activity is governed by the pore volume having the pore diameter of 2-5 microns in the honeycomb catalyst substrate and becomes higher with the increase of this pore volume having the pore diameter of 2-5 microns and also the adhering ability and resistance to catalyst poison are improved by increasing the pore volume having the pore diameter of more than 5 microns on the surface of the catalyst substrate.
text: 2, when the average particle size of the magnesia raw material is limited to the range of 5-150 microns, the resulting low-expansive and porous cordierite ceramic has a mean pore size of 2-50 microns, so that not only the adhering ability of the active material for catalyst and the catalytic component on the honeycomb catalyst substrate is excellent, but also the initial purifying efficiency for exhaust gas and the resistance to catalyst poison with a chemical substance such as lead, phosphorus and the like are improved.
text: The present invention is based on the discovery that the ceramic honeycomb consisting mainly of cordierite in crystal phase and further containing not more than 20% by weight of at least one crystal selected from the group consisting of spinel, mullite and corundum is higher in the softening temperature and melting temperature than the ceramic honeycomb consisting of cordierite alone and slow in gradient of softening shrinkage curve from the softening temperature to the melting temperature and the thermal resistance is improved, further that the ceramic honeycomb has substantially no difference in the thermal expansion coefficient from the ceramic honeycomb composed of cordierite alone, so that there is no practical problem in the thermal shock resistance.
text: Moreover, the present invention is based on the discovery that by selecting a chemical composition of 42-52% by weight of silica, 34-48% by weight of alumina and 10-18% by weight of magnesia, preferably 44-51% by weight of silica, 35-45% by weight of alumina and 11-16% by weight of magnesia, a ceramic honeycomb consisting mainly of cordierite in the crystal phase and containing not more than 35% by weight, preferably not more than 30% by weight, more preferably 1-25% by weight of at least one crystal selected from the group consisting of spinel, sapphirine, mullite and corundum can be obtained and is higher in the softening and fusing temperatures than the ceramic honeycomb consisting of cordierite alone and slow in gradient of softening shrinkage curve from the softening temperature to the fusing temperature and the thermal resistance is improved, further that the ceramic honeycomb has substantially no difference in the thermal expansion coefficient from the ceramic honeycomb consisting of cordierite alone and is high in the thermal shock resistance.
text: Further, it has been found out that the adhering ability, catalytic activity and resistance to catalyst poison are closely related to the pore structure of the ceramic honeycomb catalyst substrate, i.e. the catalytic activity is governed by the pore volume having the pore diameter of 2-5 microns in the honeycomb catalyst substrate and becomes higher with the increase of this pore volume having the pore diameter of 2-5 microns and also the adhering ability and resistance to catalyst poison are improved by increasing the pore volume having the pore diameter of more than 5 microns on the surface of the catalyst substrate.
text: 2, when the average particle size of the magnesia raw material is limited to the range of 5-150 microns, the resulting low-expansive and porous cordierite ceramic has a mean pore size of 2-50 microns, so that not only the adhering ability of the active material for catalyst and the catalytic component on the honeycomb catalyst substrate is excellent, but also the initial purifying efficiency for exhaust gas and the resistance to catalyst poison with a chemical substance such as lead, phosphorus and the like are improved.
text: The present invention is based on the discovery that the ceramic honeycomb consisting mainly of cordierite in crystal phase and further containing not more than 20% by weight of at least one crystal selected from the group consisting of spinel, mullite and corundum is higher in the softening temperature and melting temperature than the ceramic honeycomb consisting of cordierite alone and slow in gradient of softening shrinkage curve from the softening temperature to the melting temperature and the thermal resistance is improved, further that the ceramic honeycomb has substantially no difference in the thermal expansion coefficient from the ceramic honeycomb composed of cordierite alone, so that there is no practical problem in the thermal shock resistance.