Thermally Stable Nanoporous ZrO₂/SiO₂ Hybrid Aerogels for Thermal Insulation

Abstract

Compared with single-component aerogels, hybrid aerogels with multiple components possess enhanced properties, especially high thermal stabilities. Thermal stability improvement depends on the mixing between the various components. In the present research, a ZrO2/SiO2 hybrid aerogel was representatively chosen to study the mixing behaviors and resultant thermal stabilities. A series of ZrO2/SiO2 hybrid aerogels were synthesized by using different sol–gel parameters to study shrinkage, nanopore collapse, and crystallization behavior upon heat treatment. The sol–gel hybridization of weakly branched ZrO2 and SiO2 clusters was found to provide maximum mixing of ZrO2/SiO2. The highly mixed hybrid aerogel, with a ratio of 86/14 w/w ZrO2/SiO2, showed the best thermal stability. The thermally stable ZrO2/SiO2 hybrid aerogel, after incorporation into a mullite fiber blanket, showed very low thermal conductivities of 0.026 ± 0.001, 0.037 ± 0.001, and 0.058 ± 0.002 W/(m K) at 600, 800, and 1000 °C, respectively. It was suggested that weakly branched ZrO2 and SiO2 clusters preferred to freely tangle with each other during the preparation procedure, achieving the most highly mixed ZrO2/SiO2 hybrid with the maximum synergistic effect. This hybrid strategy may provide pathways in designing other multiple-component hybrid aerogels.

Phase development and pore stability of yttria‐ and ytterbia‐stabilized zirconia aerogels

“…Hybrid ZrO 2 -SiO 2 aerogels also have been studied and show promise for maintaining mesoporous structure to 1000°C. 22 The current study investigates the influence of the size of the dopant atom on phase transformation and pore structure in Y, with an atomic radius of 0.1.019 Å, and the smaller Yb atom, with a radius of 0.985 Å 23 in zirconia. Aerogels with Y and Yb doping in the range of 0-20 mol% MO 1.5 , where M = Y, Yb, or Y + Yb in equal parts were synthesized using a modification of the Chervin 20 approach.…”

“…Zhang 12 synthesized YSZ aerogels using a citric acid complexing agent, but does not report on the actual levels of yttrium incorporation achieved by this method. Hybrid ZrO 2 –SiO 2 aerogels also have been studied and show promise for maintaining mesoporous structure to 1000°C 22 …”

Ceramic Composite Materials Obtained by Electron-Beam Physical Vapor Deposition Used as Thermal Barriers in the Aerospace Industry

“…In this sense, the composite of ZrO 2 /SiO 2 aerogel have improved results under high temperature due to ultra-low thermal conductivity. Additionally, this composite presents more outstanding properties such as low density and a better heat insulation leading to a thermal stability at a temperature of 1000 • C [89,90]. However, there are some issues speaking about the mechanical strength and fragility of aerogels.…”

Nondestructive Structural Investigation of Yttria-Stabilized Zirconia Fiber Insulation Tile by Synchrotron X-ray In-Line Phase-Contrast Microtomography

“…In house construction, thermal insulation materials are generally polymer-based materials, such as polystyrene and polyurethane foam, which effectively inhibit the radiation heat of the sun or infrared rays, inhibit the heat radiation and heat loss of high-temperature objects, maintain 70% of indoor heat, effectively maintain lowtemperature objects cold, and inhibit the cooling loss caused by radiant heat loss to the environment [6][7][8]. To satisfy their use in a complex work environment, various kinds of aerogels have been developed, such as metal oxide aerogels (Al 2 O 3 , ZrO 2 ), nitride aerogels (Si 3 N 4 , BN), carbon aerogels, boride aerogels (ZrB 2 , HfB 2 ), and carbide aerogels (SiC, ZrC) [9,10].…”