Porous aluminum-containing ceramic bodies are treated to form acicular mullite crystals onto the surfaces of their pores. The crystals are formed by contacting the body with a fluorine-containing gas or a source of both fluorine and silicon atoms to form fluorotopaz at the surface of the pores, and then decomposing the fluorotopaz to form acicular mullite crystals. This process allows the surface area of the ceramic body to be increased significantly while retaining the geometry (size, shape, general pore structure) of the starting body. The higher surface area makes the body more efficient as a particulate filter and also allows for easier introduction of catalytic materials.

Porous aluminum-containing ceramic bodies are treated to form acicular mullite crystals onto the surfaces of their pores. The crystals are formed by contacting the body with a fluorine-containing gas or a source of both fluorine and silicon atoms to form fluorotopaz at the surface of the pores, and then decomposing the fluorotopaz to form acicular mullite crystals. This process allows the surface area of the ceramic body to be increased significantly while retaining the geometry (size, shape, general pore structure) of the starting body. The higher surface area makes the body more efficient as a particulate filter and also allows for easier introduction of catalytic materials.

One aspect relates to a process for producing a sintered workpiece, which includes sintering of a ceramic material at a temperature of at least 1000° C. and in an atmosphere, in the case of which the partial pressure of atmospheric air is reduced to less than 10.sup.−6-times, based on the ambient air at the same temperature under equilibrium conditions.

One aspect relates to a process for producing a sintered workpiece, which includes sintering of a ceramic material at a temperature of at least 1000° C. and in an atmosphere, in the case of which the partial pressure of atmospheric air is reduced to less than 10.sup.−6-times, based on the ambient air at the same temperature under equilibrium conditions.

Disclosed is a method for preparing an alumina-based solid solution ceramic powder by using an aluminum oxygen combustion synthesis water mist process, which comprises: drying raw materials and then mixing same until uniform to obtain a mixed material; loading the mixed material into a high-pressure reactor, igniting same in an oxygen-containing atmosphere, carrying out a high-temperature combustion synthesis reaction to form a high-temperature melt and then carrying out heat preservation for 1-60 s; and then opening a nozzle, ejecting the high-temperature melt through the nozzle and rapidly cooling same through a liquid phase, thus obtaining the alumina-based solid solution ceramic powder.

A ceramic structure includes aluminum oxide as a main component and aluminum titanate, and, in a surface layer region where a depth from a fired surface is within at least 5 mm, at least one of a surface resistance value or a surface resistivity increases in a power approximation or linear approximation manner from the fired surface in a normal direction. An electrostatic deflector includes a cylindrical substrate made of the ceramic structure and a plurality of electrodes provided on an inner peripheral portion of the cylindrical substrate.

A ceramic structure includes aluminum oxide as a main component and aluminum titanate, and, in a surface layer region where a depth from a fired surface is within at least 5 mm, at least one of a surface resistance value or a surface resistivity increases in a power approximation or linear approximation manner from the fired surface in a normal direction. An electrostatic deflector includes a cylindrical substrate made of the ceramic structure and a plurality of electrodes provided on an inner peripheral portion of the cylindrical substrate.

Methods of producing a ceramic article include heating the ceramic green body containing a quantity of one or more organic materials to extract only a fraction of the organic materials from the ceramic green body by exposing the ceramic green body to a process atmosphere which is heated to a hold temperature of from 225° C. to about 400° C. and has from 2% to 7% O.sub.2 by volume of the process atmosphere. The method further includes cooling the ceramic green body to a temperature of below 200° C., exposing the ceramic green body to a higher concentration of O.sub.2 than in the process atmosphere of the heating step, and firing the ceramic green body to form the ceramic article. Volatile extraction units for implementing the methods are also described.

A pillar shaped honeycomb structure including pillar shaped honeycomb segments joined together via joining material layers, wherein each of the pillar shaped honeycomb segment includes: an outer peripheral wall; and a porous partition wall disposed on an inner side of the outer peripheral wall, the partition wall defining a plurality of cells, each of the cells extending from one end face to other end face to form a flow path, and wherein a metal member is embedded in each of the joining material layer.

A pillar shaped honeycomb structure including pillar shaped honeycomb segments joined together via joining material layers, wherein each of the pillar shaped honeycomb segment includes: an outer peripheral wall; and a porous partition wall disposed on an inner side of the outer peripheral wall, the partition wall defining a plurality of cells, each of the cells extending from one end face to other end face to form a flow path, and wherein a metal member is embedded in each of the joining material layer.