Thermal conductivity of partially graphitized biocarbon obtained by carbonization of medium-density fiberboard in the presence of a Ni-based catalyst
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The thermal conductivity k and resistivity ρ of biocarbon matrices, prepared by carbonizing medium-density fiberboard at T carb = 850 and 1500°C in the presence of a Ni-based catalyst (samples MDF-C( Ni)) and without a catalyst (samples MDF-C), have been measured for the first time in the temperature range of 5–300 K. X-ray diffraction analysis has revealed that the bulk graphite phase arises only at T carb = 1500°C. It has been shown that the temperature dependences of the thermal conductivity of samples MDFC- 850 and MDF-C-850(Ni) in the range of 80–300 K are to each other and follow the law of k(T) ∼ T 1.65, but the use of the Ni-catalyst leads to an increase in the thermal conductivity by a factor of approximately 1.5, due to the formation of a greater fraction of the nanocrystalline phase in the presence of the Ni-catalyst at T carb = 850°C. In biocarbon MDF-C-1500 prepared without a catalyst, the dependence is k(T) ∼ T 1.65, and it is controlled by the nanocrystalline phase. In MDF-C-1500(Ni), the bulk graphite phase formed increases the thermal conductivity by a factor of 1.5–2 compared to the thermal conductivity of MDF-C-1500 in the entire temperature range of 5–300 K; k(T = 300 K) reaches the values of ∼10 W m–1 K–1, characteristic of biocarbon obtained without a catalyst only at high temperatures of T carb = 2400°C. It has been shown that MDF-C-1500(Ni) in the temperature range of 40‒300 K is characterized by the dependence, k(T) ∼ T 1.3, which can be described in terms of the model of partially graphitized biocarbon as a composite of an amorphous matrix with spherical inclusions of the graphite phase.
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- 9.R. E. Franklin, Acta Crystallogr. 4 (5), 235 (1951).Google Scholar
- 24.V. V. Shpeizman, T. S. Orlova, B. I. Smirnov, A. Gutierrez-Pardo, and J. Ramirez-Rico, Mater. Phys. Mech. 21, 200 (2014).Google Scholar
- 30.E. Ya. Litovskii, Izv. Akad. Nauk SSSR, Neorg. Mater. 16, 559 (1980).Google Scholar
- 33.D. T. Morelli and G. A. Slack, in High Thermal Conductivity Materials, Ed. by S. L. Shinde and J. S. Goela (Springer-Verlag, New York, 2006), p. 37.Google Scholar
- 35.Handbook of Physical Quantities, Ed. by I. S. Grigoriev and E. Z. Meilikhov (Energoizdat, Moscow, 1991; CRC Press, Boca Raton, Florida, United States, 1996).Google Scholar