Preparation of a Porous Cermet SOFC Anode Substrate by Gelcasting of NiO–YSZ Powders

Abstract

A porous NiO-YSZ substrate for anode-supported solid oxide fuel cells has been prepared by gelcasting of NiO-YSZ powders using urea-formaldehyde monomers, followed by humidity-controlled drying, binder removal, and sintering of the gelled bodies. The gelled bodies had sufficient strength to remove even 2-mmthick samples from the mold immediately after gelation. A gelcast NiO-YSZ sample sintered at 14501C for 2 h showed an open porosity of B53 vol%, and the porosity increased to B58% upon reduction with hydrogen. Pore sizes measured on the scanning electron microscopy photomicrograph of NiO-YSZ and Ni-YSZ cermet substrates are in the range of 2-5 lm. Urea-formaldehyde polymer, present in a high amount (B13 wt%) in the gelcast body, acts as a template for pores. P. Holtappels-contributing editor

Electrochemical performance of Ni-based anodes for solid oxide fuel cells

“…The most common way to get anodic powders is by mechanical mixing of YSZ and NiO precursors. Recently a number of studies about the preparation of enhanced Ni 1-x M x -YSZ cermets have been published proposing alternative procedure like: combustion synthesis [14], sol-gel precipitation [15], gel casting technique [16], mechanofusion method [17] and wet impregnation [18][19][20].…”

Submicron‐Scale Exclusion via Polymerizing an Aromatic Nylon in Molded Ceramic Monolith for Paving Interconnected Pore Channels

“…Among the processing techniques leading to desired porous structures, sintering a powder assembly prepared by shape‐forming processes such as pressing, slip casting, tape casting, and plastic molding at a nondensification temperature has been studied extensively 10 . Other porous ceramic techniques including freeze casting, 11,12 sol–gel method, 13 gel‐casting method, 14–16 and the replica technique 17 have been developed recently to meet various requirements. However, none of these techniques have achieved higher popularity compared with using sacrificial pore formers such as carbon black, methylcellulose, carbon wax, and starch 18–20 .…”

Preparation of PZT Microtubes by Slip Casting on Vermicelli, Followed by In Situ Polymerization

“…The process is called gel casting 15,16 . Acrylic and urea–formaldehyde (UF) monomers are widely studied for gel casting of ceramic powder suspensions 15–18 . Slip casting of highly concentrated PZT powder suspensions, prepared in an aqueous solution of organic monomers, on vermicelli, followed by in situ polymerization would produce PZT microtubes with thicker walls at a lower dipping time.…”

“…Slip casting of highly concentrated PZT powder suspensions, prepared in an aqueous solution of organic monomers, on vermicelli, followed by in situ polymerization would produce PZT microtubes with thicker walls at a lower dipping time. Of a number of monomers available, the UF monomer would be advantageous for the slip‐casting process as its acid‐catalyzed polymerization is not inhibited by oxygen present in the atmosphere 17,18 . Moreover, polymerization of the monomers would be possible by exposing PZT‐coated vermicelli to acid (HCl) fumes.…”

“…15,16 Acrylic and ureaformaldehyde (UF) monomers are widely studied for gel casting of ceramic powder suspensions. [15][16][17][18] Slip casting of highly concentrated PZT powder suspensions, prepared in an aqueous solution of organic monomers, on vermicelli, followed by in situ polymerization would produce PZT microtubes with thicker walls at a lower dipping time. Of a number of monomers available, the UF monomer would be advantageous for the slip-casting process as its acid-catalyzed polymerization is not inhibited by oxygen present in the atmosphere.…”