Abstract According to the CCT-WG5s requirement of Co-C eutectic fixed point to all measurement institutions, a filling system was designed and built, using the direct eutectic filling method filled Co-C cells, all cells met the requirement of realizing the Co-C eutectic fixed point. An improvement program was put forward which aimed at solving the disadvantages of direct filling method: low filling efficiency and high probability of crucible breaking, and two Co-C eutectic fixed points were filled successfully. The result of realizing the Co-C-2# eutectic fixed point is that the uncertainty of ascertaining the inflection point temperature was 5.3 mK, which CCTs requirement is less than 10 mK; the short-term repeatability was 9.6 mK, which CCTs requirement is less than 20 mK.
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2019, Vol. 40 
