Discipline: Technology and Engineering
Subcategory: Materials Science
Aleysha Vargas - University of Puerto Rico-Mayaguez
Co-Author(s): Juan C. Vargas-Martinez and Oscar Marcelo Suárez, University of Puerto Rico-Mayaguez
Nanoporous metals are innovative materials that can be formed by selective dissolution of a given alloy. These types of materials are used in electronic devices, photonic devices, sensors, biochips and in applications requiring catalytic processes. In particular, the said dissolutions of Al-Sn alloys can turn a polished, smooth surface into a porous specimen. The present research seeks to produce porous aluminum with an optimum pore size by selective corrosion of Al-Sn specimens. To this purpose, an Al-Sn alloy was quenched from the liquid state to refine the microstructure. The ingot was then cut into individual 1cm2 pieces and polished to prepare the surface. Afterwards, the alloy specimens underwent selective electrochemical corrosion, using a potentiostat apparatus to measure the current and determine the current density, while applying voltages between -2.5 and -1.5V. We employed electrochemical methods to study both the anodic and cathodic polarization curves, thus obtaining the pitting current range that would define the optimal conditions to control pore size. These methods were analyzed in naturally aerated 0.01 M, 0.1 M, and 1 M sulfuric acid and nitric acid at room temperature. Data was collected via electrochemical characterization, x-ray diffraction, scanning-electron microscopy, and image analysis. We have successfully managed to selectively remove tin from the Al-Sn alloy while creating aluminum with pore sizes at the microscale. In summary, this research demonstrates how porous aluminum can be produced from an Al-Sn alloy, while using aluminum as the cathodic element, where in most applications it had been used as an anodic element. Ongoing and upcoming research centers on the use of different aluminum alloys and acids to reduce and homogenize the pore size of these types of materials, while varying the treatment temperature upon accelerated corrosion to assess and control the dissolution rate.
Funder Acknowledgement(s): This material is based upon work supported by the National Science Foundation under Grant No. 1345156 (CREST Program Phase II). Special thanks to the Composite Materials Research Group.
Faculty Advisor: Oscar Marcelo Suárez, firstname.lastname@example.org
Role: As part of the research team, I took part in quenching of the Al-Sn alloy ingot and prepared the surface of each of the 1cm2 pieces by polishing them. Furthermore, I participated in the selective corrosion of the specimens by electrochemical corrosion, using the potentiostat apparatus. Subsequently I participated in the collection of the data by means of electrochemical characterization, image analysis, scanning-electron microscopy and x-ray diffraction.