Preliminary study of the anodizing process of aluminum with pyroligny liquor in galvanostatic and potenciostatic modes using the Hard Anodization technique

ABSTRACT

The Hard Anodization technique was developed to optimize the porous aluminum anodizing process, generating high anodization rates, with accelerated and organized growth of the oxide layer, combining high voltages applied in the process with electrolytes at low temperature. The pyroligneous liquor is a well-known product in the agricultural environment, being a mixture of liquid organic compounds derived from the condensation of smoke from charcoal production. Thus, the aim of this study is to evaluate the technical feasibility of using pyroligneous liquor as an anodizing electrolyte for aluminum using Hard Anodization. The anodizing parameters were defined (time, temperature, voltage and current density) suitable for Hard Anodization in pyroligneous liquor electrolyte and compared to 1% acetic acid. Electrochemical tests were conducted in galvanostatic and potentiostatic mode. The samples were evaluated morphologically, by scanning electron microscopy (SEM) and optical microscopy, and for their wettability characteristics. The results showed that the pyroligneous liquor is capable of anodizing aluminum at low oxide growth rates, and that the best anodizing mode was galvanostatic. Under the process conditions used, acetic acid behaved as an electropolishing electrolyte for aluminum.

Keywords
Aluminum; Pyroligneous liquor; Hard Anodization