6533b85afe1ef96bd12b9673
RESEARCH PRODUCT
Microporous alumina membranes electrochemically grown
Francesco Di QuartoPatrizia BocchettaCarmelo SunseriGiovanni Pietro Chiavarottisubject
AnodizingGeneral Chemical EngineeringOxalic acidInorganic chemistrychemistry.chemical_elementElectrolyteOxalatechemistry.chemical_compoundAluminium anodizing Anodic porous oxide Ceramic membrane Membrane preparation Porous aluminaCeramic membraneMembranechemistryAluminiumElectrochemistryPhosphoric aciddescription
Abstract The electrochemical fabrication of alumina membranes by anodizing of aluminium in phosphoric acid and oxalic acid solutions, in the temperature interval from −1 to 16 °C, was investigated in order to study the influence of different parameters (initial treatment of aluminium surface, nature and composition of electrolyte, temperature) on the final characteristics of the membranes. Porous layers were grown using a linear potential scan at 0.2 V s −1 up to 160 V in H 3 PO 4 solution and 70 V in oxalic acid solution. The efficiency of porous layer formation was calculated by using Faraday's law and weight measurements. Pore size distribution and porosity of membranes prepared in 0.4 M H 3 PO 4 were found to be dependent on temperature, while in 0.04 M smaller pore size and lower porosity were obtained, independent of temperature. Highly ordered structures were formed by aluminium anodizing in 0.15 M oxalic acid solution at 70 V. A uniform pore diameter of about 90 nm was found, independent of temperature. A porosity value of about 26% was achieved and it was found to be independent of temperature for membranes prepared in oxalic acid. Porous layers grown either in H 3 PO 4 or oxalic acid solution crystallized at temperatures around 870–890 °C. For membranes formed in oxalic acid the pyrolysis of oxalate anions also occurs.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2003-09-01 | Electrochimica Acta |