Ngk Insulators, Inc.

Shunichi Yamada

Toshiyuki Hamanaka

Yutaka Ogawa

Shigeru Mochida

Takashi Harada

A heat insulating ceramic insert-cast article for an internal combustion engine, comprising a ceramic liner and a metallic member enclosing an outer periphery of the ceramic liner. The ceramic liner is adapted to contact exhaust gases. A joint boundary between the ceramic liner and the metallic member is constituted by contact faces at which the ceramic liner contacts the metallic member and heat insulating air layers at which the ceramic liner and the metallic member do not contact each other. A process for producing such a heat insulating ceramic insert-cast article is also disclosed. First, the outer periphery of the ceramic liner is covered with the heat insulating layer which is partially formed with cuts, and then the ceramic liner is enclosed with a molten metal in the state that the ceramic liner is covered with the layer. Thus, the metal flows into the cuts and solidifies therein to form contact faces between the ceramic liner and the metal, while portions at which the metal does not flow inside due to the pressure of the layer are converted to heat insulating layers.

Heat insulating ceramic insert-cast articles for use in exhaust channels

Highly gas-tight rotary cordierite heat regenerator is formed of a honeycomb structural body having a porosity of 20-45% and mainly consisting of cordierite, and open pores of the partition walls defining channels of the honeycomb structural body are sealed with a filler thereto, the difference of thermal expansion between the honeycomb structural body and the filler being less than 0.1% at 800.degree. C. The honeycomb structural body is made by preparing fired segments thereof, sealing the open pores of the partition walls with the filler thereof, bonding the segments with a ceramic bonding material, and firing the bonded segments.

Rotary cordierite heat regenerator highly gas-tight and method of

A ceramic material for a honeycomb structure is formed from a mixture of raw materials comprising, per 100 parts by weight of the mixture, 20 to 80 parts by weight of cordierite powder and 20 to 80 parts by weight of powder having a crystalline phase consisting mainly of a solid solution of SiO.sub.2 --Al.sub.2 O.sub.3 --Fe.sub.2 O.sub.3 --TiO.sub.2 --MgO. The mixture consists essentially of 15.7 to 44.0% by weight of SiO.sub.2, 29.8 to 41.0% by weight of Al.sub.2 O.sub.3, 0.9 to 8.3% by weight of Fe.sub.2 O.sub.3, 7.0 to 35.9% by weight of TiO.sub.2 and 4.9 to 16.1% by weight of MgO.

Ceramic material for a honeycomb structure

A ceramic material for a honeycomb structure is prepared from a mixture of raw materials comprising per 100 parts by weight of the mixture 40 to 90 parts by weight of cordierite powder and 10 to 60 parts by weight of crystalline glass powder having a crystalline phase consisting mainly of a solid solution of .beta.-spodumene. The mixture consists essentially of 51.5 to 64.4% by weight of siO.sub.2, 24.8 to 33.7% by weight of Al.sub.2 O.sub.3, 5.5 to 12.4% by weight of MgO and 0.4 to 2.7% by weight of Li.sub.2 O. It may further contain up to 5.1% by weight of TiO.sub.2 and up to 1.8% by weight of ZrO.sub.2.

The disclosed method seals preselected open ends of channels of a ceramic honeycomb structural body with cordierite-forming sealing material batch, and fires the honeycomb structural body with the thus sealed ends, so as to convert the sealing material batch into cordierite.

Method of sealing open ends of ceramic honeycomb structural body

The disclosed method seals preselected open ends of channels of a ceramic honeycomb structural body by attaching a film to that end surface of the honeycomb structural body which is to be selectively sealed while boring holes on the film at positions corresponding to desired open ends of the channels to be sealed, dipping the end surface in a sealing material containing slurry, pressing sealing material mixture body in the desired channels open ends, and then firing the ceramic honeycomb structural body with the sealing materials applied thereto.

Growing community of inventors

Nagoya, Japan

Shunichi Yamada