Patent ID: 6027684
Filing Date: 2000-02-22
Classification: C04B

Abstract:
A method of fabricating a cordierite honeycomb structural body comprising the steps of:formulating a batch of raw materials comprising a mixture of kaolin clay, talc, alumina and other cordierite-forming materials, each of the raw materials included in the batch in an effective amount, which in combination with the other raw materials therein, is capable of yielding a fired honeycomb body whose predominant crystal phase is cordierite;intimately blending the raw materials with an effective amount of vehicle and forming aids to impart plastic formability and green strength to the raw materials and to form a plastic mixture;forming the raw materials into a green honeycomb structural body by extrusion and thereafter drying the green honeycomb structural body;firing the green honeycomb structural body by heating the green body to a first temperature range between about 750-850.degree. C. and thereafter to a second temperature range between about 1250 to 1350.degree. C. and thereafter to a third temperature of at least 1390.degree. C., and thereafter maintaining the temperature at the third temperature for a soak period of about 12 to 20 hours, wherein an oxidizing firing atmosphere comprising O.sub.2 in an amount up to about 5% is maintained for the first and second temperature ranges, an oxygen content of about 1% O.sub.2 is maintained for the third temperature range and an oxygen content of about 2% O.sub.2 is maintained for the soak period.