Ultralight alumina ceramic foams with single-grain wall using sodium dodecyl sulfate as long-chain surfactant

A novel and facile method for the fabrication of alumina ceramic foams based on particle-stabilized foam method was proposed. Alumina foams with ultrahigh porosity of 94.7-98.3% (density 0.067-0.210 g/cm3) were fabricated for the first time using long-chain surfactant sodium dodecyl sulfate (SDS) as particle hydrophobization modifier. Sintered foams possess single-grain wall and uniform cells with cell size in the range 50-200 μm. Ultra-stable wet foams can be fabricated in a very wide pH range (from 4.0 to 9.0) due to strong adsorption ability of SDS on alumina particles, which is beneficial for massive production. Effect of pH value on SDS adsorption and foam properties were studied. The influence of solid loading and sintering temperature on properties of alumina ceramic foams were also investigated. Alumina foams with porosity of 97% have compressive strength above 0.5 MPa, which could fulfill the needs of some engineering fields where high closed porosity is beneficial.