If are present in the material the carbon will collect into microscopic pockets during the sintering process. These pockets disrupt the Tungsten Carbide/Cobalt matrix and can affect the properties of the material.
Because the pockets like A and B type porosity C type porosity is rated by the ASTM at different levels. C-00 (carbon porosity free) up to C-08, but these rating do not correspond to total pore volume like A and B type porosity.
