A Novel Way to Prepare Hollow Sphere Ceramics

Abstract

Recent developments in the fabrication of hollow spheres have allowed our group to prepare a new type of macroporous ceramics: hollow sphere ceramics (HSCs). Alumina hollow spheres were first produced by centrifugal spray‐drying of particle‐stabilized foam slurry. The obtained hollow spheres were sintered together to form HSC at high temperatures. The effect of the sintering temperature on the linear shrinkage, porosity and compressive strength of HSC samples was investigated. When the sintering temperature was increased from 1400°C to 1600°C, the samples shrunk increasingly and the porosity decreased from 59% to 42%, which lead to an increase in the strength of the alumina foams from 6.9 (at 1400°C) to 100.0 MPa (at 1550°C). The mechanical strength of the HSC highly depends on the contact area between the hollow spheres, which could be increased by increasing the sintering temperature, decreasing the size of hollow spheres or by slurry infiltration.

Al2O3 hollow nanospheres prepared by fluidized bed chemical vapor deposition and further heat treatment

“…1,2 The large fraction of empty spaces endows them fascinating properties such as large surface area, low density, and high loading capacity, and demonstrates a large variety of applications, including micro-/ nanoreactors, catalysis, energy storage, biomedicine, sensors, environmental remediation, and so forth. 4 So far, various routes such as template method, 5-8 spray drying, 9,10 wet-chemical synthesis, 11 and flame spray pyrolysis have been developed to prepare Al 2 O 3 hollow micro-/nanospheres. 4 So far, various routes such as template method, 5-8 spray drying, 9,10 wet-chemical synthesis, 11 and flame spray pyrolysis have been developed to prepare Al 2 O 3 hollow micro-/nanospheres.…”

Synthesis of low-cost porous ceramic microspheres from waste gangue for dye adsorption

“…Qi et al [12] developed hollow sphere ceramics (HSCs) with porosity decreased from 59% to 42% when the sintering temperature was 1400-1600 ℃. Consequently, the spray drying method was applied to fabricate glass foams and hollow sphere ceramics, which was considered to be prospective, low-cost, and widely used in industrial applications.…”

Phase evolution and properties of novel Al2O3-based poly-hollow microsphere (PHM) ceramics

“…Therefore, choosing proper pore-forming agent is considerably important. In recent years, ceramic poly-hollow microspheres (PHMs), a kind of special material with porous microstructures, have been  successfully produced via combination of particlestabilized foams and centrifugal atomizing technology [19,20], which could be used as novel promising pore-forming agent to prepare porous ceramics.…”

“…In addition, Qi et al [20] proposed a novel route to prepare porous ceramics using Al 2 3 , respectively. Figure 1 shows the scanning electron microscopy (SEM) micrographs of the calcined Si 3 N 4 and Al 2 O 3 PHMs.…”