[en] The sintering of pure and doped boron carbide was investigated over the temperature range 1898 to 2380⁰K and at additive levels ranging from 0.75 to 10.0%. The addition of 0.75 and 3.8 wt% of AlF₃, Ni, Fe, and Cu deactivated the sintering of B₄C at all temperatures. In contrast, the addition of 10.0 wt% these additives resulted in enhanced shrinkage in B₄C for the temperatures 1898 and 2133⁰K. At the highest temperature, 2380⁰K, the addition of 10.0 wt% AlF₃ was the only case where enhanced shrinkage was observed. In this case, x-ray analysis showed the formation of a B₁₂C₂Al compound and the release of fluorine. These results are interpreted in terms of a grain-boundary diffusion process for pure and doped B₄C