Abstract: A ceramic substrate having a plurality of holes arranged regularly with a specified pitch can be used for an universal high density ceramic wiring board, wherein predetermined one or more holes among said plurality of holes are used as through holes for interconnecting both side circuits, and the remaining holes not used for a circuit are filled with an electrical insulating material.Said ceramic substrate of universal type can easily be produced inexpensively and within a short lead time, because said substrate requires no individual mold for each of various circuits to punch a green sheet and can be kept in stock as a fired ceramic substrate.

Abstract: A porous silicon carbide sinter and its production process, the sinter consisting mainly of silicon carbide and having a three-dimensional network structure composed mainly of silicon carbide plate crystals having an average aspect ratio of 3 to 50 and an average length along the direction of the major axis of 0.5 to 1,000 .mu.m, wherein the open pores in the network structure have an average sectional area of 0.01 to 250,000 .mu.m.sup.2.

Abstract: A heat-resistant, highly expansible sheet material for supporting a catalyst carrier containing unexpanded vermiculite, in which the cations contained between the layers of the vermiculite are at least partly exchanged by ammonium cations, is provided. A process for the preparation of the sheet material, which involves blending an unexpanded vermiculite which has been preliminarily immersed in an aqueous solution containing alkali metal ions, inorganic fiber, an organic binder, and an inorganic binder, whereto a slurry solution of beaten natural organic fiber is added, and forming a sheet material from the mixture, is described.

Abstract: A ceramic substrate having a plurality of holes arranged regularly with a specified pitch can be used for an universal high density ceramic wiring board, wherein predetermined one or more holes among said plurality of holes are used as through holes for interconnecting both side circuits, and the remaining holes not used for a circuit are filled with an electrical insulating material.Said ceramic substrate of universal type can easily be produced inexpensively and within a short lead time, because said substrate requires no individual mold for each of various circuits to punch a green sheet and can be kept in stock as a fired ceramic substrate.

Abstract: A printed circuit board having a multi-layered copper plating film with excellent mechanical characteristics is obtained by a process of non-electrolytic copper plating comprising at least one sequence of the following steps (a)-(d):(a) immersing the printed circuit board to be plated in a non-electrolytic copper plating bath;(b) drawing out the immersed board from the bath;(c) immersing the drawn out board in the bath; and(d) drawing out the immersed board from the bath.In place of using one non-electrolytic copper plating bath, two non-electrolytic copper plating baths containing same solutes and having different concentration of the solutes in baths and/or different temperature of the baths respectively are used alternately.

Abstract: A powder composition for producing sintered ceramic, which composition contains fluororesin powder which has not been used in the prior art as one of the materials constituting a molding assistant to be blended in the composition. With this composition, it is possible to produce a high-density green molding with few molding defects under a relatively low molding pressure. The invention also provides a process for producing such a composition.

Abstract: In a method of producing a silicon carbide sintered compact comprising steps of placing silicon carbide fines, a sintering additive and a shaping additive as required into a dispersing medium solution to form a supensoid, sieving operation on said suspensoid, forming a green shape from powders obtained in said sieving operation, and pressureless sintering process; an improvement characterized is that solid content comprising said silicon carbide fines and sintering additive is limited within a range of 10-50% by volume to said suspensoid, and that in the sieving operation, the suspensoid is passed through a sieve having an opening less than 65 .mu.m under a pressure differential between before and after the sieve to remove coarse particles in the silicon carbide fines, sintering additive and others to form silicon carbide sintered compact having a high strength.

Abstract: A process for producing an ultrafine silicon carbide powder by passing a granulated blend of silica powder, carbon powder and a carbonaceous binder downwardly through a vertical indirect heating reactor, wherein means are provided for increasing the bulk density of the carbon powder for preventing the disintegration of the blend during the reaction which might result from the use of ultrafine powder as the carbon powder in the blend.

Abstract: A powder composition for producing sintered ceramic, which composition contains fluororesin powder which has not been used in the prior art as one of the materials constituting a molding assistant to be blended in the composition. With this composition, it is possible to produce a high-density green molding with few molding defects under a relatively low molding pressure. The invention also provides a process for producing such a composition.