Obtenção de superfície seletiva do tipo armadilha ótica via oxidação por plasma eletrolítico

Abstract

High performance solar collectors are those with selective surfaces, with high absorption of solar radiation and lower reflectance of heat radiation. One of the new strategies to improve this performance involves modifying its surfaces to obtain an optical trap structure. In this work, the plasma treatment technique called Plasma Electrolytic Oxidation (PEO), was tested to produce porosity on aluminum surfaces by a controlled manner. For this, we used a pulsed square wave voltage power supply applied at the following frequency 10 kHz. The applied current densities were 0.12, 0.15 and 0.17 A / cm2 . In addition to these variables, the duty cycle was also changed by 30, 50 and 70%. And each treatment was performed for different times duration, 2, 4 and 6 min. After the treatments, the surfaces were evaluated for their microstructure, chemical composition and optical properties. Porous aluminum oxide surfaces were produced, which are capable of absorbing radiation in the UV-Vis-NIR range. Among all treated samples, the sample treated for 6 minutes, with 70% duty cycle and 1 A applied current, was the sample that showed the most efficient absorption of solar radiation for application in the manufacture of solar collectors.