Porous Alumina Ceramics with Multimodal Pore Size Distributions

Area of Science:

• Materials Science
• Ceramic Engineering
• Nanotechnology

Background:

• Optimizing porous ceramics requires multimodal pore size distributions.
• Combining isotropic and anisotropic pores enhances physical properties.

Purpose of the Study:

• To manufacture multimodal porous Al2O3 ceramics using sacrificial templates.
• To investigate the influence of pore structure on mechanical and thermal properties.

Main Methods:

• Utilized pyrolyzed cellulose fibers and phenolic resin spheres as sacrificial templates.
• Employed uniaxial pressing, burnout, and sintering up to 1700 °C.
• Characterized properties via 4-point bending, laser flash analysis (LFA), and micro-computed tomography (µCT).

Main Results:

• Achieved porosities ranging from 0-60 Vol% by varying template content up to 67 Vol%.
• Mechanical strengths varied from 173 MPa to 14 MPa; thermal conductivities ranged from 22.5 Wm-1K-1 to 4.6 Wm-1K-1.
• Fiber-rich templates enhanced strength, while sphere-rich templates reduced thermal conductivity.

Conclusions:

• Pore network architecture in Al2O3 ceramics can be precisely controlled by adjusting template composition and volume.
• The study demonstrates a method for tailoring ceramic properties for specific applications.
• Multimodal pore structures significantly impact mechanical and thermal performance.