Development and Realization of Fe–C and Co–C Eutectic Fixed-Point Blackbodies for Radiation Thermometry at CSIR-NPL

摘要: A series of metal–carbon (M–C) eutectics with robust reproducible melting phase transitions are evolving as the reference high-temperature fixed-points up to 3000 °C for radiation thermometry. The mise-en-pratique prepared realization and dissemination new kelvin allows use set M-C blackbody or a combination along silver (Ag), gold (Au) copper (Cu) blackbodies direct measurement thermodynamic temperatures at range. iron–carbon (Fe–C) [1153 °C] cobalt–carbon (Co–C) [1324 °C] fixed-point cells doorway high temperature above fixed-point. This paper describes in-house development Fe–C Co–C eutectic graphite crucible their realizations by linear spectral pyrometer (LP4, 650 nm) CSIR-NPL, National Metrology Institute (NMI) India. novel design assembly approaches were employed fabricate crucibles 120o inner-well cone, 100 mm ingot length 8 mm aperture diameter 0.9997 emissivity thermo-mechanical stability. ingots multiple fillings homogeneously ground mixed powders 4.2 2.6 weight percentage carbon in Fe Co, respectively. Repeatability measured plateau uncertainty both presented. ITS-90 (T90) these assigned radiance ratio (Planck’s Law) relative freezing point Ag [961.78 °C]. T90 thus determined 1154.05 °C 1323.93 °C expanded 0.37 °C 0.50 °C,