MISHRE , M and BORA , J J and GOSWAMEE, R L
(2011)
Improvement of the mechanical strength of alumina performs by coating with montmorillonite / LDH ge.
Applied Clay Science , 53 (1).
pp. 8-14.
Abstract
AcompositematerialwaspreparedfrommontmorilloniteandMg–AlLDH.Theseoppositelychargedparticles
form thixotropic gels with distinctflow and micro-structural properties. The stability of the gel was
dependent on the montmorillonite/LDH ratio. Novel advanced ceramic materials were designed by coating
ceramic preforms with these gels. During calcination these gels decompose to metal oxides, aluminosilicates
and spinel. On calcination at 1400 °C, MgO formed from the LDH of the gel reacted with the aluminosilicate
formed by the decomposition of the montmorillonite. A non-porous dense matrix was formed with well
grown crystals of MgAl2O4 spinel embedded in the aluminosilicate matrix. When the ceramic preforms like
porous alumina tube were dip coated with the gel andfired at 1400 °C, the molten aluminosilicate infiltrated
into the pores of the aluminum oxide carrying spinel crystals. These spinel crystals settled in the pores and
increased the mechanical strength of the alumina tubes. The compressive strength was increased by around
94% and the mechanical extension in the z-direction in the coated body by 4% compared to the uncoated
counterpart.
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