Sintering is a fairly complex process where the porous fraction of body (green part) decreases when exposed to elevated temperature (meaning a significant fraction of the melting temperature) for a certain time in a certain atmosphere. Finding the optimal conditions would require knowing which properties are being designed for in your system, i.e. high relative density, high strength, a specific porous network etc. Then you would need to run a series of experiments to determine what conditions give an optimal mix of properties.
A good "rule of thumb" though is 30% to 50% of melting temperature gives a reasonably fast sintering rate without causing too much grain growth (assuming you are talking about crystalline materials). If for some reason that is not possible you will have to investigate more exotic techniques like adding a liquid phase sintering aid or applying high pressure before, during or after an initial densification.
Sintering is a fairly complex process where the porous fraction of body (green part) decreases when exposed to elevated temperature (meaning a significant fraction of the melting temperature) for a certain time in a certain atmosphere. Finding the optimal conditions would require knowing which properties are being designed for in your system, i.e. high relative density, high strength, a specific porous network etc. Then you would need to run a series of experiments to determine what conditions give an optimal mix of properties.
A good "rule of thumb" though is 30% to 50% of melting temperature gives a reasonably fast sintering rate without causing too much grain growth (assuming you are talking about crystalline materials). If for some reason that is not possible you will have to investigate more exotic techniques like adding a liquid phase sintering aid or applying high pressure before, during or after an initial densification.
Generally 2/3 of melting temperature is a good starting condition, but many other parameters should be taken into account like green density and specific surface of the starting material sintering aids and so on. So you need to test different conditions to find the best final properties.
Sintering is a very complex phenomena and the temperature will be determined by the microstructure you want to achieve. Higher temperature usually give higher densities but with increased grain growth. Pay attention to phase transformations that can some times help you or can leave artefacts that are hard to eliminate afterwards. A designed experimental plan can help you to quickly optimise your sintering profile, you "just" need to know what you want exactly and that's probably the hardest part!
there are oa lot of sintering method (natural sintering, HIP, SPS etc..)
it depend what propertiesdo you want
you can use a DSC and dilatometry for detecting the temperatures of differents transformations
Hocine: DSC is indeed a good tool to find out transition temperatures. I could also suggest adding thermochemical calculations (FactSage, Thermocalc, etc.) to get pertinent the phase diagrams.
Jean François Dionne
Thank you
I don't know exactly the material to be sintered
I think the differential of dilatometric curve gives the exact temperature phase transfomations
there is also the measurement of thermoelectric power (TEP) (pouvoir thermo electrique pour les diagrammes de phase)
For initial experiments we use this rule:
For single-phase powder the technical sintering temperature is about
2/3 to 4/5 of the solidus temperature. A multi-phase powder
(Powder mixtures) is sintered near or above the solidus temperature of the lowest melting phase.
Additionally, it depends on whether you want to do solid state sintering or liquid phase sintering.
The sintering temperature depend on many items such as material, sintering time, Solid phase/liquid phase sintering, sintering atmosphere, component size, particle size of powder ,... . But this temperature is typically 60-70% melting temperature. However, I would like to read following useful book:
Sintering Theory and Practice
Randall M. German
ISBN: 978-0-471-05786-4
568 pages
February 1996
As per general thumb rule, Sintering Temperature can be considered= 0.8TM (TM-Melting Temperature of metal)
Hi Sim
As far I have understood the problem, in case of metals you can Measure it in terms of %FC ( Fusing Current,the current which required to fuse metal ) and you can plot a graph between current applied and Temprature.Then determine the current required to fuse the metal and Temprature corresponding to 40% FC will be the temprature of sintering.You also have to confirm it by microstructural analysis of Samples.
Although there are different methods mentioned in various satandards for different metals.
Please tell specifically in what case you have measure the Sintering Temprature.
Regards
Sorry, my question is not clear.
The sintering of porous materials for use as photoanode.
Also are there any in depth books on perovskite and ferroelectric?
This question is in reference to Christopher's answer,
what if for the multi-powder sintering, the solidus temperature( which is considered for sintering) is above the melting point of one of the constituents i.e. though we don't want liquid phase sintering to take place but is un-avoidable because of low melting constituent present , so how to pursue it further, while doing solid state sintering to attain the same theoretical density?
The sintering temperature depend to many items: type of materials, type of furnace, type of sintering cycles (sintering time), size and number of parts in furnace, compaction method of green part, green density,......
But generally for the ceramics is higher than of metals.
"Dilatometry can be used to find the calcination and sintering temperature"
I have read the sintering temperature is 0.8 to 0.9 of melting temperature,whereas the sintering time has also to be looked in.
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