Annealing : A process in which the material is thermally treated to release stresses produced during the ceramic-forming process. In glasses, annealing stabilizes the glass structure to produce homogeneous material and to avoid property variation from region to region.
Calcination : A ceramic process that involves converting metal salt precursors, such as carbonates, oxalates, alkoxides, sulfates, nitrates, and acetates or oxides, into desired crystalline oxides or other nonoxide single or multi component compounds. The variables involved in this process include temperature, pressure, gaseous atmosphere, and calcination time. The variables determine the crystallinity, grain, size, and other physical properties of the final material. For example, when basic magnesium carbonate (MgCO3) is calcined at 550°C, a pseudomorphed MgO is formed, whereas when calcination is performed at 900°C, crystalline MgO (approaching cubic) is produced. In another example, BaCO3 and TiO2 are calcined at 1100°C to form perovskite BaTiO3.
Sintering: The process of densifying a polycrystalline or amorphous body with or without the aid of a liquid phase. In the sintering process, the compacted ceramic is heated close to the solidus (melting temperature) to effectively bond the grains in the compacted powder for maximum density. Extensive studies have been conducted to investigate the effects of pore sizes and shapes, grain sizes and shapes, and porosity on the sintering process and the properties of the densified material
In metallurgy, annealing is a heat treatment of metal to reduce its strength thereby increasing its ductile behaviour.
Sintering mainly in ceramics and powder metallurgy is heating or firing of a powder prepared material at a high temeprature but below its melting temperature.
Calcination is also a heat treatment which involves low temperature maily to render the material non plastic in case of traditional ceramics
Lawrence L Sutter
Michigan Technological University
University of Campinas
Dr. T. HariPrasad
Sree Vidyanikethan Engineering College
Gadjah Mada University
University of Leeds
Amit Kr Vishwakarma
Delhi Technological University
Materials and Energy Research Center