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DRYING 5
- Thread starter mechnano
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2
- #2
Drying implies removing water, so the temperature would be higher than 100 [°]C, but not much above it.
Sintering is a process in which atomic diffusion is activated by heating to a temperature that is a significant fraction of the melting temperature. For many materials, this can be above 1000 [°]C, so the temperature differences between drying and sintering are enormous.
Regards,
Cory
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Sintering is a process in which atomic diffusion is activated by heating to a temperature that is a significant fraction of the melting temperature. For many materials, this can be above 1000 [°]C, so the temperature differences between drying and sintering are enormous.
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
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- #3
The temperature does not need to be above boiling to effect drying.
Evaporation and transpiration commonly occur at temperatures well below boiling. Common examples are clothes driers, hair driers and hand driers. Many industrial drying processes occur below boiling.
Sublimation - by definition - occurs below the freezing point.
Evaporation and transpiration commonly occur at temperatures well below boiling. Common examples are clothes driers, hair driers and hand driers. Many industrial drying processes occur below boiling.
Sublimation - by definition - occurs below the freezing point.
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- #5
mechnano,
I work in the investment casting industry so I have some background in the drying of ceramics. First off, let me give you a good reference that explains the theory behind drying:
"Theory of Drying". Journal of the American Ceramic Society. Vol - 73. Pages 3-14. 1990 by Gearge W Scherer.
Drying and sintering aren’t the same but in most cases they are used in succession. In the process of drying water evaporates from the surface. The surface tension between the liquid and solid phase causes a contraction in the solid network (more eloquently called a gel). This contraction forms van der waals bonds between the solids. This is why the network stiffens. Sintering would be the next step. Pressure/heat is applied to the solid network. The individual grains bond together. This description of sintering is an oversimplification but more detail would require too much writing. I hope this helps.
Regards,
Matlsguy
I work in the investment casting industry so I have some background in the drying of ceramics. First off, let me give you a good reference that explains the theory behind drying:
"Theory of Drying". Journal of the American Ceramic Society. Vol - 73. Pages 3-14. 1990 by Gearge W Scherer.
Drying and sintering aren’t the same but in most cases they are used in succession. In the process of drying water evaporates from the surface. The surface tension between the liquid and solid phase causes a contraction in the solid network (more eloquently called a gel). This contraction forms van der waals bonds between the solids. This is why the network stiffens. Sintering would be the next step. Pressure/heat is applied to the solid network. The individual grains bond together. This description of sintering is an oversimplification but more detail would require too much writing. I hope this helps.
Regards,
Matlsguy
As corypad already pointed out, drying and sintering are two different processes. Drying means only the removal of water from something. Sintering actually means the interfacial reaction between two or more phases in contact with each other under elevated temperature (but below their softening or melting points). Reactions at the interfaces through atomic diffusion will form a transitional zone to link the phases so that they sintered together.
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