Mechanical Properties of Aerogel-Ceramic Fiber Composites

Abstract

Aerogel composites were prepared by immersing ceramic fiber into silica aerogel precursor via supercritical fluid drying. The mechanical behavior of silica aerogel composites was investigated with shrinkage, tension, bending and compression. The influences of fiber volume fraction, aerogel density and heat treatment were examined. After reinforced by ceramic fiber, the shrinkage of aerogel and aerogel-fiber composites was retarded obviously. The mechanical property of aerogel-fiber composites increased first and then decreased with increasing fiber volume fraction from 5.8% to 11.5%. For a given fiber volume fraction, the mechanical strength enhanced with increasing aerogel density. In addition, the mechanical property of aerogel composites did not decrease but increased after heat treatment at 600°C.

Three-Dimensional Graphene Hybrid SiO2 Hierarchical Dual-Network Aerogel with Low Thermal Conductivity and High Elasticity

“…Figure 8b shows that the GA could elastically deform with a maximal strain as large as 80%; the primary structure was not damaged, indicating outstanding elasticity to overcome a large deformation of the hierarchical structure on the multiscale. However, pure GA showed a relatively low Young's modulus of 0.023 MPa, the stepped increases of compressive strength (0.0026, 0.0041, 0.0067, and 0.0170 MPa corresponding to strains of 20%, 40%, 60%, and 80%) demonstrated a typical intensification effect as similar as most insulation materials (Table 2) [31,32]. Comparatively (Figure Figure 8b shows that the GA could elastically deform with a maximal strain as large as 80%; the primary structure was not damaged, indicating outstanding elasticity to overcome a large deformation of the hierarchical structure on the multiscale.…”

Effects of non-ideal structures and high temperatures on the insulation properties of aerogel-based composite materials

“…where α 1 and α 2 are the volume fractions of SiO 2 and Al 2 O 3 within the fibers, which are assumed to be α 1 = 0.95 and α 2 = 0.05 [12]. k SiO2 and k Al2O3 are the thermal conductivity of SiO 2 and Al 2 O 3 , Wm − 1 K − 1 , respectively, given by the correlations [30] k SiO 2 = 0:75255+0:00313T−4:52647 × 10 −6 T 2 +3:52637 × 10 −9 T …”

“…As a result, there will be an optimal loading and distribution of the fibers and opacifiers for these composite materials. To improve the performance of the composite materials, some researchers have focused on the effects of the types, loading and the distribution of fibers on the mechanical and insulating performance of the composite materials [8][9][10][11][12][13]. To reduce radiative heat transfer, lots of attempts have been made to investigate the effects of the type, loading, and distribution of opacifiers on the radiation extinction coefficient of the composite materials [14][15][16][17][18][19][20].…”

“…The performance of silica aerogels is improved by adding fibers or other hard materials to the aerogels to enhance their mechanical strength and toughness [7][8][9][10][11][12][13]. Some mineral powders, such as TiO 2 , SiC, carbon black or potassium titanate whiskers (KT 6 ), are also loaded into the aerogels as opacifiers to reduce the radiation heat transfer, which is especially important at high temperatures [14][15][16][17][18][19][20].…”

Preparation of SiO2 nanocomposites with aligned distributing glass fibre using freeze-drying process

“…Therefore, it is very important to improve the mechanical properties of silica aerogel by proposing and designing new approach [4]. Among various methods, fibres are often employed as reinforcement phase to strengthen the mechanical performance of the base material [1,[5][6][7][8][9][10][11][12]. Wu et al proposed a possible way to control the thermal and mechanical properties of fibrereinforced aerogels composites by regulating the fibre alignments and the laminated structures [2,4].…”