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!
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.
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:
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.
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.
The choice of sintering temperature is determined by the growth of ceramics grains because there is a temperature point where the rate of grain growth increases sharply. For example, this point for YAG ceramics is 1750 °C.