The ceramic powder along with suitable additives are placed in a die, to which pressure may be applied for compaction. Uniaxial pressing is often used for small shapes such as ceramics for electrical devices. Hydrostatic pressing (equivalent pressing from all sides) is often used for large objects.
Alternatively, the ceramic powder may be cast. Although molten ceramics may be cast into cooled metal plates and quenched to produce materials made up of very fine crystals with high material toughness, casting of ceramics is usually done at room temperature. The ceramic particles are first suspended in a liquid and then cast into a porous mold that removes the liquid, leaving a particulater compact in the mold.
Yet another method of shaping a ceramic involves plastic forming. In this process a mixture of ceramic powder and additives is deformed under pressure. In the case of pure oxides, carbides, and nitrides, an organic material is added in place of or in addition to water to make the ceramic mixture plastic. While forming the ceramic object, heat and pressure are usually applied simultaneously.
Science EncyclopediaScience & Philosophy: Categorical judgement to ChimaeraCeramics - Traditional Ceramics, Glass, Aluminum Oxide, Silicon Carbide, Silicon Nitride, Processing, Forming Processes - Hydraulic cement, Modern ceramics, Magnesium oxide, Sintering, Machining