They are right about the Wikipedia, but I guess you wanted a correlation between all these processes, which doesn't exist.

Each process that you have mentioned is not competing with the others.

Annealing

Is a process in metallurgy, a heat treatment, that removes defects on the crystalline planes, therefore reducing internal stresses and increasing ductility of metallic alloys.

Sintering

Another process in metallurgy, more specifically in powder metallurgy, is very common to manufacture ceramic objects but is also used to produce metals (mostly the ones with complex form and low machinability) and cermets. There you mill the material to obtain a powder, press it into a mold using a binder like paraffin to “stick it together”, go inside the sintering furnace (high temperature + high pressure) to fuse the powder particles together and create a solid piece.

Calcination

Although it’s also a thermal treatment, that is used to do a thermal decomposition, mostly of minerals. The most common application is the decomposition of calcium carbonate (limestone) to calcium oxide (lime) and carbon dioxide, in order to produce cement.

Differently from the other two processes, it’s not used to process metallic alloys during its production chain.

Go to Wikipedia. There you will find excellent answers.

http://en.wikipedia.org/wiki/Annealing_%28metallurgy%29

http://en.wikipedia.org/wiki/Sintering

http://en.wikipedia.org/wiki/Calcination

Hope these answers help

They are right about the Wikipedia, but I guess you wanted a correlation between all these processes, which doesn't exist.

Each process that you have mentioned is not competing with the others.

Annealing

Is a process in metallurgy, a heat treatment, that removes defects on the crystalline planes, therefore reducing internal stresses and increasing ductility of metallic alloys.

Sintering

Another process in metallurgy, more specifically in powder metallurgy, is very common to manufacture ceramic objects but is also used to produce metals (mostly the ones with complex form and low machinability) and cermets. There you mill the material to obtain a powder, press it into a mold using a binder like paraffin to “stick it together”, go inside the sintering furnace (high temperature + high pressure) to fuse the powder particles together and create a solid piece.

Calcination

Although it’s also a thermal treatment, that is used to do a thermal decomposition, mostly of minerals. The most common application is the decomposition of calcium carbonate (limestone) to calcium oxide (lime) and carbon dioxide, in order to produce cement.

Differently from the other two processes, it’s not used to process metallic alloys during its production chain.

annealing- heat treatment of substance in presence of O2.

sintering - respiration process in presence of O2.

Calcination- In metallurgy the conversion of CaCO3 in to CaO and CO2.

I agree with the reply of Salavdor Edo. These terms are frequently used in metallurgy as well as in glass and ceramic industry. I do not know from which perspective you ant to analyze them but essentially they carry almost similar meaning in both the fields. I have seen many people using the term ´annealing´ or ´calcination´ for any kind of heat treatments but this is incorrect. In glass and ceramic field, annealing is a term which usually refers to removal of stress from a glass by heating a glass below its glass transition temperature. Sintering refers to the coalescence of powders by softening them under the influence of heat treatment. Sintering is of 2 types: i) solid state sintering (usually used in case of glasses and ceramics); ii) Liquid state sintering (mostly used in metallurgy). About calcination, it is removal of CO2 from any material by heating it upto its decomposition temperature. For example: CaCO3 and MgCO3 convert to CaO and MgO at 900ºC by removing CO2.

Thank you for the explanation.

There are some corrections that need to be made in some of the previous replies.

Annealing of metals is used to reduce the strength and hardness and increase the ductility. It can take place in air or in neutral or reducing atmospheres, but usually is done in air.

Annealing of glass is used to reduce internal stresses arising from molding and other processes. It always is done in air.

Sintering is not a “respiration” process.

Sintering of glass powders takes place by viscous flow.

Sintering of traditional ceramics, including pottery, tile, sanitary ware, dinnerware, etc., takes place in the presence of a viscous liquid, and it typically includes chemical changes as well. For instance, the clay in the original material decomposes.

Sintering of technical ceramics often involves a small amount of liquid, or it can take place in the solid state by atom diffusion.

Sintering of powder metals can take place with our without a liquid phase.

Sintering of cermets, such as tungsten carbide-cobalt, takes place with liquid metal (cobalt in this case) and solid carbide (or nitride, etc.) in a reducing atmosphere or vacuum.

Sintering of powder metals, except perhaps Pt, has to be done in a reducing atmosphere or vacuum.

Calcining is much broader than simply removing CO2 from carbonates. It involves decomposition of any suitable salt to form an oxide, including carbonates, nitrates, hydroxides, sulfates, and others.

Briefly,

Annealing = thermal treatment to remove strain effects on metal, glasses, etc.

Sintering = thermal treatment that lead to particles agglomeration or pores colapsing.

Calcination = Thermal treatment under oxidative (O2 or air) atmosphere.

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 mainly to render the material non plastic in case of traditional ceramics

What does mean firing in PV industry with respect to annealing?

Thanks

Regards

what is the meaning of sintering in air at 723K?

cani use furnace to do that?

Calcination is a heat treatment in order to decompose the materials and to achieve the desired phase through heat treatment above the decompose temperature of at least one of the reactant and below their melting point.

Sintering  (post-calcination process)  is performed at a temperature below the melting point of the desired phase in order to improve crystal quality by minimizing defects, enhance grain growth (reducing the total area of grain boundary) and to achieve maximum possible density.

Annealing is a process of minimizing crystal defects through a heat treatment.

This can help:

https://cmfurnaces.com/annealing-sintering-and-calcining-processes/