The secondary debinding and sintering are carried out in the same furnace in a single step. After the secondary debinding is completed, the furnace ramps on to the sintering temperature and sinters the parts.
The secondary or backbone binder holds the metal or alloy particles together until the powders start bonding by diffusion. The binder must be removed without leaving residues in the part in the form of carbon or other inorganic materials to ensure that the composition of the powder is not contaminated or compromised.
The binder must also be removed in a manner slow enough so not to crack or distort the part by the force of the binder material leaving the part. The debind hold must be long enough to remove all the binders.
At the end of the secondary debinding, when all the binders are removed from the part, the interparticle necks formed are very fragile the part is not strong enough to be handled. The temperature may be now ramped up to the sintering temperature to sinter the parts.
During sintering, when temperatures are as high as 0.8 times the melting point of the material in degrees Celsius, the bond between the particles form and grow in most cases by the mechanism of solid state diffusion. This leads to the elimination of pores and causes the shrinkage and densification of the part.
The final size of the part depends on the powders used, the binder content of the feedstock, and the shrinkage factor of the feedstock as well as the processing and sintering parameters.
We can help you choose the right equipment, processing and sintering parameters for your material to produce the part that you want.