Ceramics

PressingUsed in the fabrication of relatively thick-walled pieces such as plates and dishes.

Blowing

DrawingUsed to form long glass pieces, such as sheet, rod, tubing, and fibers, that have a constant cross section.Up until the late 1950s, sheet glass (or plate) was produced by drawing the glass into a plate shape, grinding both faces to make them flat and parallel, and finally, polishing the faces to make the sheet transparent.Fiber FormingGlass fiber is formed when thin strands ofsilica-based or other formulation glass areextrudedinto many fibers with small diameters suitable fortextileprocessing.The technique of heating and drawing glass into fine fibers has been known for millennia; however, the use of these fibers for textile applications is more recent.Powder PressingUsed to fabricate both clay and nonclay compositions, including electronic and magnetic ceramics as well as some refractory brick products.The degree of compaction is maximized and fraction of void space is minimized by using coarse and fine particles mixed in appropriate proportions.

Schematic Diagram showing the float process for making sheet glassSlip CastingA slip is a suspension of clay and/or other nonplastic materials in water. The slip must have a high specific gravity and yet be very fluid and pourable.Tape Castingacastingprocess used in the manufacture of thinceramic tapesfromceramicslurry

HotWith hot pressing, the powder pressing and heat treatment are performed simultaneouslythe powder aggregate is compacted at an elevated temperature. Used for materials that do not form a liquid phase except at very high and impractical temperaturesUniaxialThe powder is compacted in a metal die by pressure that is applied in a single direction. The formed piece takes on the configuration of die and platens through which the pressure is applied. IsostaticThe powdered material is contained in a rubber envelope and the pressure is applied by a fluid, isostatically. DryingAs a clay-based ceramic body dries, it also experiences shrinkage.During drying it is critical to control the rate of water removal. Drying at interior regions of a body is accomplished by the diffusion of water molecules to the surface where evaporation occurs.A body that has been formed and dried but not fired is termed as green.FiringDuring the firing operation, the density is further increased and the mechanical strength is enhanced.Vitrification is the gradual formation of a liquid gas that flows into and fills some of the pore volume.

Several stages in the removal of water from between clay particles during the drying process.