Comparative Properties of Porous Phyllosilicate-Based Ceramics Shaped by Freeze-Tape Casting

Kassoum Barry,Mohamed Seynou,Philippe Blanchart,Claire Peyratout,Michael Faucher,Gisèle Laure Lecomte-Nana

doi:10.3390/ceramics5010007

Kassoum Barry, Mohamed Seynou + Show 4 more

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https://doi.org/10.3390/ceramics5010007

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Abstract

Porous phyllosilicate-based ceramics were manufactured by freeze-tape casting from clays of different particle size and morphology in order to characterize their microstructure and stress to rupture changes before and after firing. Three raw clays were selected: HCR (77% Halloysite–10Å), KORS (29% kaolinite), and KCR kaolin (98% kaolinite). These clays exhibited a monomodal distribution and were used to prepare four slurries, three with each clay material and one consisting of a mixture of KCR and HCR labeled KHCR. After shaping by freeze-tape casting, the porosity and stress to rupture obtained by a biaxial flexural test were collected for disk-like samples after drying and sintering at 1200 °C. Results showed that KCR ceramic materials had the highest biaxial bending strength (70 ± 1.1 MPa) and those from KORS had the highest porosity value (80 ± 1%). SEM observation revealed a difference in microstructure and texture for the manufactured porous ceramic materials. In the KCR ceramic disks, the flattened pores appeared more textured, and the primary mullite crystallites formed a rigid skeleton within the amorphous phase. KORS ceramic materials showed a small quantity of secondary mullite needles which were randomly dispersed in a vitreous phase. The relatively important vitreous phase in the porous materials of HCR led to the bulk formation of small mullite particles. The biaxial flexural strength values were related to the presence of the mullite, as well as to the microstructure (volume, morphology, and size distribution of pores) after sintering.

Highlights

IRCER (Institut de Recherche sur les Céramiques), Université de Limoges, 12 Rue Atlantis, LC2M (Laboratoire de Chimie Moléculaire et des Matériaux), Unité de Formation et de Recherche en Sciences
The aim of this work is to manufacture textured and porous ceramics based on natural clays rich in kaolinite or halloysite by the process of freeze-tape casting
The objective of this work was to characterize the microstructure and mechanical resistance of porous textured ceramics, which are produced by the freeze-tape-casting process

Summary

Introduction

IRCER (Institut de Recherche sur les Céramiques), Université de Limoges, 12 Rue Atlantis, LC2M (Laboratoire de Chimie Moléculaire et des Matériaux), Unité de Formation et de Recherche en Sciences. In the field of water treatment, membrane technology (microfiltration, ultrafiltration, or nanofiltration) is considered an effective means of water purification [5,6,10] and in particular, ceramic membranes are widely studied owing to their excellent mechanical properties, thermal stability, high chemical resistance, and long life cycle [1,11] These porous and textured ceramics can be produced by different methods, such as compaction [1,3], sol–gel [12], extrusion [13], hydrothermal synthesis [14], and gel casting [15]. The incorporation of a pore-former or porogen published maps and institutional affiliations

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