Fabrication of Porous Mullite Ceramics with Different Phase of Alumina for Insulation Materials

Abstract

This paper reports the effects of γ-Al2O3 and α-Al2O3 on the properties of lightweight insulation materials. The phase compositions, microstructure and mechanical properties of lightweight insulation materials are separately investigated by XRD, SEM and tabulate thermal conductivity apparatus methods. The results indicate that the increasing of the amount of γ-Al2O3 is beneficial to improving the bulk density, compressive strength and acid resistance of the fired specimens. The fact negatively impacts on the increasing of the apparent porosity; however, it has no significant effect on the thermal conductivity of specimens. Meanwhile, the studies highlight that when the content of γ-Al2O3 increases, the nucleation and growth of mullite is accelerated at high calcination temperature, which has positive effect on improving the physicochemical properties of lightweight insulation materials. And the γ-Al2O3-free SiO2 glass phase system is guided by theoretical analysis of reaction conditions for non-catalytic system with Factsage modelling.

FOAM-GELCASTING PREPARATION OF Zr Si O₄ MODIFIED POROUS MULLITE CERAMICS

“…Porous mullite ceramics are good insulation materials possessing superior properties like high melting (1850 o C), small thermal expansion, chemical inertness, lightweight and low thermal conductivity [1][2][3][4]. Various strategies/methodologies have been adopted to fabricate them, including sacrificial template [5,6], gel/freeze casting [7,8], particle stacking [9,10], use of pore-former [11,12] as well as foam-gelcasting [13,14]. Compared with other techniques, the foam-gelcasting technique shows several advantages, for example, it is easy to operate, low cost, and scalable, and the resultant products exhibit excellent properties and performance [14,15].…”

Corrosion Resistance Properties of Porous Alumina–Mullite Ceramic Membrane Supports

“…Numerous works have focused on the corrosion behaviors of the ceramic membrane supports such as alumina, cordierite, Al 2 O 3 –TiO 2 or mullite or Al 2 TiO 5 –mullite, mineral‐based ceramic (kaolin, dolomite, pyrophyllite, ballclay, and feldspar), and SiC, under various corrosion media including H 2 SO 4 , HCl, HNO 3 , H 3 PO 4 , HF, NaOH, KOH. The results show that the corrosive attack generally occurs at grain boundaries, in which impurities/glass concentrated, leading to the deteriorations of mechanical properties and chemical stability of the ceramics.…”