Permeability and corrosion resistance of the porous alumina doped by Y₂O₃ with monodispersed PMMA as pore former

Abstract

Porous alumina, with monodispersed PMMA as pore former and Y2O3 as sintering additive, was prepared via a gel casting route with Isobam as a gelling agent. The effects of PMMA addition on its properties, including apparent porosity, bulk density, strength, permeability, and corrosion resistance to acid/alkali, were investigated. With PMMA addition increased, the apparent porosity and permeability were increased obviously, while strength and corrosion resistance to acid/alkali were deteriorated due to increased porosity. Higher firing temperature resulted in lower porosity, higher strength, lower permeability, and better corrosion resistance to acid/alkali. Coarser raw powders resulted in lower strength and higher permeability due to the coarser structure and larger pores of the fabricated samples. Because Y2O3 was used as a sintering additive, and no silica was introduced, the resulting samples possess better corrosion resistance to acid and alkali, especially much better corrosion resistance to alkali, than those reported with silica introduced.

Permeability and corrosion resistance of porous SiOC‐bonded SiC ceramics prepared by the preceramic polymer

“…Gas permeability of airflow was evaluated using a laboratory-made air-permeator described elsewhere. 29,30 The pressure gradient in the sample was calculated using Equation ( 2) because of the compressibility of the air…”

“…Gas permeability of airflow was evaluated using a laboratory‐made air‐permeator described elsewhere 29,30 . The pressure gradient in the sample was calculated using Equation (2) because of the compressibility of the air $$$$\begin{equation}{\rm{\;}}\frac{{dP}}{{dL}} = \frac{{P_i^2 - P_o^2}}{{2{P_o}L}},\end{equation}$$$$where $$\frac{{dP}}{{dL}}$$ is pressure gradient, L is the sample thickness, P i is the pressure of the inlet gas, P o is the pressure of the outlet gas 31 .…”