Preparation of form-stable carbonates/magnesium oxide-flake graphite composite thermal storage material and its thermal conductivity

doi:10.12028/j.issn.2095-4239.2019.0054

Abstract

Abstract: The medium-and high-temperature composite heat storage materials were fabricated by the mixed sintering method using mixed carbonates as phase change materials, magnesium oxide as ceramic matrix material, and graphite flakes as heat transfer enhancer. Based on the characterizations of XRD and SEM, the resultant composite materials have shown enhanced chemical stability, as well as more pore structures due to the presence of graphite flakes. By analyzing the thermal properties of the composite materials with different contents of graphite flakes, it can be found that the melting points of the composite materials remain unchanged and their thermal conductivities increase continuously with the increase of the content of graphite flakes. When the content of graphite flakes is up to 25%, the thermal conductivity of the composite material reaches 3.88 W/(m·K) and 2.52 W/(m·K) at 250℃ and 560℃, respectively. The enhancement mechanism of thermal conductivity of the composite materials is further discussed from the view of the microstructure and interface layer theories.

Key words: composite materials, molten salt, graphite flakes, thermal properties, thermal conductivity

CLC Number:

TK512

SANG Lixia, XU Yongwang, LI Feng, ZHANG Yating, MA Wentong, CHEN Xu, WANG Hao. Preparation of form-stable carbonates/magnesium oxide-flake graphite composite thermal storage material and its thermal conductivity[J]. Energy Storage Science and Technology, 2019, 8(5): 886-890.

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