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In situ synthesis and thermal shock resistance of a cordierite‐mullite composite for solar thermal storage
Author(s) -
Cheng Hao,
Ye Fen,
Chang Jun,
Wu Sizhan
Publication year - 2018
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/ijac.13135
Subject(s) - materials science , mullite , cordierite , composite material , thermal shock , microstructure , composite number , sintering , flexural strength , scanning electron microscope , ceramic
Cordierite‐mullite composite ceramic was synthesized in situ by semidry pressing and pressureless sintering from andalusite, kaolin, γ‐Al 2 O 3 , talc, potassium feldspar, and albite in air. The effects of composition and sintering temperature on the density, bending strength, thermal shock stability, crystal phases, and microstructure of the specimens were studied. The results show that specimen B2 (the theoretical content of cordierite was 20 wt%) has excellent performance, that is, a bending strength of 104.59 MPa, 30 cycles of thermal shock resistance without cracking, and a loss rate of 13.12%. X‐ray diffractometer ( XRD ) analysis and scanning electron microscope ( SEM ) micrographs showed that spherical cordierite crystals were grown on the surface of the mullite, therefore, the specimen possessed a superior bending strength and thermal shock resistance, where a great number of granules combined to restrain crack initiation as well as propagation over time during the thermal shock test. The thermal conductivity of specimen B2 was determined to be 3.83 W/(m·K) (36°C), and the sensible heat storage density was 1136 kJ/kg, with the temperature difference (Δ T ) ranging from 0 to 800°C. Consequently, the cordierite‐mullite composite is a potentially applicable material for solar thermal storage.