Abstract

This study prepared gradient pore structure ceramics from silica fume through direct foaming. The rheological behavior of the slurry was improved by varying the solids content. Physical and mathematical models were developed to describe the longitudinal movement of foam in the ceramic slurry and the mechanism of gradient pore formation. These models were used to predict the pore sizes at different heights within the ceramic. Insulation and mechanical properties were enhanced by optimizing the gradient pore structure. The gradient pore structure resulted in significant directional differences in specimen properties. Additionally, suitable sintering-temperatures for gradient pore structure ceramics are discussed. The results indicate that gradient pore structure ceramics were prepared when the solid content ranged from 55 wt.% to 62.5 wt.%. After sintering at 900 °C, the shrinkage was 2.06 %. The apparent porosity and bulk density were 70.82 % and 0.59 g/cm³. The Flexural strength in the two directions is 0.89 MPa and 1.22 MPa, while the compressive strengths were 2.07 MPa and 4.10 MPa. The thermal conductivity of the ceramics showed a gradient variation from 0.13 to 0.117 W/(m·K) from the top to the bottom. The coefficient of thermal expansion reached a maximum value of 5.565 x 10−6·1/°C at 200 °C.

Department(s)

Materials Science and Engineering

Publication Status

Full Text Access

Comments

State Key Laboratory of Refractories and Metallurgy, Grant 52302013

Keywords and Phrases

Gradient pore structure; Mathematical model; Mechanical properties; Porous ceramics; Rheological properties

International Standard Serial Number (ISSN)

0950-0618

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2025 Elsevier, All rights reserved.

Publication Date

08 Aug 2025

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