Ceramic parts of complicated configurations with different thicknesses at different portions can be mass produced economically with high production yield and excellent quality using an injection molding process.

Method of producing ceramic parts

A method of joining two pre-sintered pieces of silicon carbide is disclosed. It entails polishing the surfaces to be joined to a mirror-finish, fitting the polished surfaces together to form a composite structure, and then subjecting the composite structure to hot isostatic pressing under conditions which are sufficient to form a joint which is essentially indistinguishable from the original silicon carbide pieces.

Joining of SiC parts by polishing and hipping

Synthetic raw materials are used to prepare a sintered refractory body consisting essentially of cordierite having 47.5 to 56 weight percent SiO2, 31 to 40 weight percent Al2O3, 12 to 19 weight percent MgO, and 0.15 to 1 weight percent CaO, the body having a flexural strength of at least 138 MPa (20,000 psi). The cordierite body, with respect to impurities, has less than 0.3 weight percent total alkaline earth metal oxides other than MgO and CaO, less than 250 ppm Na2O, less than 150 ppm K2O and less than 500 ppm transition metals on the oxide basis. Thus, the cordierite of the invention has very low impurity levels yet good sinterability and, hence, high strength.

Strengthened cordierite having minor amounts of calcia

A process is provided for the manufacture of thin walled ceramic structures, particularly conical or near conical shaped structures. The process involves a tape casting technique wherein a green tape is prepared from a colloidal suspension containing a ceramic powder, a binder system, a plasticizer and a solvent. The suspension is cast into a thin sheet and dried to form a pliable tape. The tape is cut into planar, shaped pieces. Non-planar components of the final structure are preformed from the cut planar tape pieces into predetermined three dimensional shapes. The planar and preformed components are sequentially assembled within a die and compacted under pressure to form a green body. The green body is subjected first, to a burnout cycle to form a brown body, and then sintered to form the unitary, cohesive, thin walled ceramic structure.

Process for the production of thin walled ceramic structures

A method of producing a sintered body (1) having different cross-sections along a main axis (5), in particular a toothed-belt or chain wheel, by compression moulding a sintering powder in the direction of the main axis (5) and subsequent sintering. At least two partial bodies (6, 7), which can be form-fitted into each other in the direction of the main axis (5), are pressed from sintering powder, which partial bodies each form an axial portion of the sintered body (1) with different cross-sections, and that the separately pressed and possibly presintered partial bodies (6, 7) are jointly sintered after joining them together.

Method of producing a sintered body

In the manufacture of an article of ceramic material, for example a bladed turbine wheel of silicon nitride, there is first formed a plurality of article parts, at least one of which is a shaped powder body formed from powder of ceramic material mixed with a plasticizer, after which the plasticizer is driven off by a suitable heating operation. The article parts are then assembled together into a configuration conforming to that of the article to be manufactured, and the assembled article parts are surrounded with a gas-impermeable layer, for example a layer of glass. Finally, the assembled parts are isostatically pressed at elevated temperature to form the assembled article parts into a dense, homogeneous article.

Method of manufacturing articles of ceramic material

Verfahren zur herstellung von keramischen gegenstaenden aus pulver

An object of a metallic material or other ceramic material than silicon nitride or than a material having silicon nitride as its main component is manufactured by isostatic pressing of a body preformed from a powder of the metallic or ceramic material, whereby the preformed body is embedded in glass, for example embedded in a mass of glass particles, and the embedment, with the body and the embedment placed in a vessel which is dimensionally stable at the temperature at which the sintering of the metallic or ceramic material is carried out, is transferred to a melt having a surface limited by the walls of the vessel, below which surface the preformed body is located, and a pressure necessary for the isostatic pressing of the preformed body then being applied on the melt by a gaseous pressure medium.

Mattsson B

Papers

Method of manufacturing articles of ceramic material

Verfahren zur herstellung von keramischen gegenstaenden aus pulver

Method related to isostatic hot pressing of preformed bodies of a metallic or ceramic material

Sett att framstella ett foremal av ett pulverformigt material genom isostatisk pressning