Metals or metal compounds with a high chemical affinity for the heteroatoms in the carbons. They are distributed as fine particles within the carbon materials to be graphitized.
Note: Iron and iron compounds are most frequently used as puffing inhibitors when puffing is related to sulfur.
Source: PAC, 1995, 67, 473. (Recommended terminology for the description of carbon as a solid (IUPAC Recommendations 1995)) on page 502 [Terms] [Paper]