Cobalt Lake in T.C Products
The tungsten carbide products are produced with powder metallurgy process ,in which the metal binder phase takes the function to sinter together of the carbide phase .However ,after sintered ,there are too much cobalt existing in one place of the sturcture ,which is called “cobalt lake” .As the incomplete distributing of the cobalt in sinter process resulting of the cobalt lake mainly due to the following three causes.
1) The sintering temperature is too low and the cobalt is unavailable to flow smoothly
2) The density of compact virgin material is insufficient
3) The porosity is filled with the cobalt in the HIP process
The evaluation of the volume of cobalt lake in the T.C materials has been done with comparison of micrograph or measurement one by one as per its size and distribution .
The exist of cobalt lake in tungsten carbide products is adverse to its wear-resistance and transverse rupture strength .
