Thermal Conductivity of Bulk Attapulgite Prepared by Pressureless Sintering

doi:10.16183/j.cnki.jsjtu.2021.254

Abstract

Abstract:

To explore the potential of attapulgite as thermal barrier materials, bulk attapulgite samples were prepared by pressureless sintering. The effects of sintering temperature on the phase composition, porosity, microstructure, and thermal conductivity of bulk attapulgite were investigated. With increasing sintering temperature, bulk attapulgite transforms from predominant quartz phase (700 ℃) to coexistence of quartz and enstatite phases (800—900 ℃), and to coexistence of quartz, enstatite and cristobalite phases (1000—1200 ℃). Meanwhile, the microstructure of the bulk attapulgite changes from random, loose packed fiber-like porous morphology, to dense structure with a random distribution of MgO·SiO₂ grains inside the SiO₂ matrix to result in a significant decrease in porosity. The thermal conductivity of bulk attapulgite increases with increasing temperature. When sintered at 700 ℃, bulk attapulgite presents a temperature-independent thermal conductivity with an ultra-low value of 0.16 W/(m·K) at room temperature. Attapulgite, with its natural abundance and low cost, along with the ultra-low thermal conductivity, has a great potential as thermal barrier materials.

Key words: attapulgite, pressureless sintering, thermal conductivity, thermal barrier materials

CLC Number:

SUN Xucheng, ZHAO Xiaofeng, YANG Fan. Thermal Conductivity of Bulk Attapulgite Prepared by Pressureless Sintering[J]. Journal of Shanghai Jiao Tong University, 2023, 57(2): 194-200.

Figures/Tables 8

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热处理温度/℃	f_i/%			ρ_t/ (g·cm^-3)	ρ/ (g·cm^-3)	φ/%
热处理温度/℃	石英	顽火辉石	方石英	ρ_t/ (g·cm^-3)	ρ/ (g·cm^-3)	φ/%
700	100	0	0	2.647	1.342	49.30
800	18.3	81.7	0	3.099	1.639	47.11
900	25.9	74.1	0	3.057	1.678	45.11
1 000	8.5	87	4.5	3.107	2.310	25.65
1 100	6.8	84.5	8.7	3.073	2.560	16.69
1 200	1.2	86.4	12.4	3.066	2.747	10.40