Ngk Insulators, Inc.

Kyoko Makino

Yasushi Noguchi

Wataru Kotani

Toshiyuki Hamanaka

Takehiko Watanabe

There is disclosed a ceramic structure which comprises a material having a controlled pore distribution and including cordierite as the main crystal phase. In the pore distribution, the volume of pores having pore diameters smaller than 20 &#x3bc;m accounts for 15% or less of the total pore volume, and the volume of pores having pore diameters of 20 to 100 &#x3bc;m accounts for 70% or more of the total pore volume. This ceramic structure is suitable for realizing a ceramic catalyst body which has excellent purification efficiency, is reduced in pressure loss, and is mountable even in a limited space.

Ceramic structure and process for producing the same

A process for producing a honeycomb structure, which comprises adding water to a mixed raw material of a raw material powder and a binder, kneading the mixture to obtain a plastic mixture, molding the plastic mixture into a honeycomb shape to obtain a green honeycomb structure, drying the structure by a step including hot-air drying, and firing the resulting dried honeycomb structure, wherein the binder contains hydroxypropyl methyl cellulose as a major component. The process can produce a crack-free high-quality honeycomb structure rapidly at a low cost.

Process for production of honeycomb structure

A process for producing a ceramic structure, which comprises adding an organic assistant to a ceramic raw material mixture, kneading them to obtain a readily formable bullet, and extruding the readily formable bullet to obtain a ceramic structure, wherein the organic assistant is composed mainly of an organic compound giving a haze of 10 to 90% when made into a 5 weight % aqueous dispersion. According to the process, the load to the extruder is small and a ceramic structure can be produced at high shapability and a high productivity.

Process for production of ceramic structure

A method of producing a cordierite ceramic honeycomb including the steps of: preparing raw materials becoming cordierite and forming agents; adding the forming agents into the raw materials for cordierite generation; mixing the forming agents and the raw materials to obtain a raw material batch; extruding the raw material batch to obtain a formed body; drying the formed body; and sintering the formed body after drying; so as to obtain a honeycomb structural body having a cordierite crystal phase as a main ingredient. In this method, at the sintering step, a temperature descending rate at least from a maximum temperature to 1300&deg; C. is not larger than 100&deg; C./hour.

Method of producing cordierite ceramic honeycomb

A ceramic honeycomb catalyst carrier wherein a porosity is 20% or less and an average surface roughness (Ra) of a partition wall of the carrier is 0.5 &mgr;m or more is obtained by forming ceramic raw materials to obtain a ceramic honeycomb formed body; drying the ceramic honeycomb formed body to obtain a ceramic honeycomb dried-up body; roughening a surface of the partition wall of the ceramic honeycomb dried-up body by exposing the ceramic honeycomb dried-up body in an airflow in which polishing powders are included; and sintering the ceramic honeycomb dried-up body after a surface treatment, or, by forming ceramic raw materials to obtain a ceramic honeycomb formed body; drying and sintering the ceramic honeycomb formed body to obtain a ceramic honeycomb sintered body; and roughening a surface of the partition wall of the ceramic honeycomb sintered body by exposing the ceramic honeycomb sintered body in an airflow or a water flow in which polishing powders are included.

Ceramic honeycomb catalyst carrier and method of producing the same

A process for producing a cordierite-based ceramic honeycomb structure, includes kneading raw materials for cordierite with a forming aid to obtain a raw material batch, subjecting the raw material batch to obtain a honeycomb structure, and subjecting the honeycomb structure to drying and firing in this order to obtain a ceramic honeycomb structure whose crystal phase is composed mainly of cordierite. The raw material batch contains 65% by weight or more of raw materials for cordierite, comprising talc, kaolin and aluminum hydroxide and having crystal water. The kaolin has an average particle diameter of 5 &mgr;or more and a BET specific surface area of 10 m,/g or less and is contained in the raw material batch in an amount of 10% or more by weight. Formability during extruding, particularly lubricity and shape stability, are improved, for producing cordierite-based ceramic honeycomb structure having thin partition walls and high cell density, and improved mechanical strength (isostatic fracture strength) and improved catalyst coatability.

Process for production of cordierite-based ceramic honeycomb structure

A production method of a cordierite ceramic honeycomb structure is provided. 0.1 to 2% by weight of a nonionic polyether lubricant, obtained by adding ethylene oxide and propylene oxide to polyhydric alcohol with an ethylene oxide:propylene oxide ratio of 10:90 to 100:0 by weight, is added to the cordierite material batch for extruding. The honeycomb structure has a thin partition wall, and is suitable for the mass production by improving the formability (in particular, the lubricity and the shape stability) in extruding.

Production method of cordierite ceramic honeycomb structure

A production method of a cordierite ceramic honeycomb structure is provided. Clay mineral, which is one component in the cordierite material batch for extruding, contains dickite and at least one selected from the group consisting of kaolinite and halloysite, with a 5 to 50% by weight dickite amount in the clay mineral. The honeycomb structure has a thin partition wall, and is suitable for the mass production by improving the formability (in particular, the lubricity and the shape stability) in extruding and by preventing crack generation in the firing process.

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Nagoya, Japan

Kyoko Makino