A Method for Fabricating Stainless Steel Pellets with Open‐Cell Porosity by Alkaline Leaching of Silica Template

Abstract

In this paper, a method of fabricating metallic analogues of biological materials is presented.In particular, the structure of pre-pressed oilseed used for physical modeling of supercritical CO 2 extraction of desired substances is replicated in a material commonly used for manipulation of foods, i.e. food grade stainless steel (AISI 316L).Powder metallurgy approach is employed through sintering the steel powder with SiO 2 spacer and further leaching the porogen. The resulting metal framework has interconnected porosity and low apparent density (about 1.91 g/cm 3 ). The prospect of tuning the balance between porosity and interconnectivity of pores is of special concern to allow mimicking the structure of natural materials intended for supercritical CO 2 extraction. With this motivation, the effects of initial silica content (between 20 to 60 vol.%) and silica particle size (small: 0.5-10 µm, medium: 110 µm, and large: 170-630 µm) on the structural and mechanical properties of the porous material are studied. It is found that increasing porosity correlates with decreasing compressive strength, whereas the plateau region of the stress-strain relationship in compression is of lower slope and spans over larger strain. Yield strength ranges from 4.2 MPa to 220 MPa, which is sufficient for sustaining the conditions of supercritical extraction.

Sucrose derived microporous–mesoporous carbon for advanced lithium–sulfur batteries

“…iii) Template method which has been used to the synthesis of porous carbon materials. Many templates such as silica pellets [20], porous silica [21], molecular sieves [22] etc. have been developed in recent years as sulfur host.…”