The Determination of Optimum Conditions for Anodizing Aluminum Alloy (6063)


Aluminum alloy (6063) has been anodized using sulfuric acid as anelectrolyte. To study the characteristic of the anodic film, four variables, wereconsidered as the most dominant variables. These variables are: current density in therange of 1- 4 A/dm2, electrolyte concentration in the range of 6 - 20 vol.%, electrolytetemperature in the range of 10- 30oC and anodizing time between 12- 60 min.These four variables are manipulated through the experimental work using Box –Wilson experimental design where second order polynomial model was proposed tocorrelate the studied variables with the thickness of anodic film of aluminum alloy(6063) to estimate the coefficients of the proposed polynomial adopted via statisticasoftware.The predicated models are found after statistically analyzing the significance asfollows:Y= 27.7800 + 8.0737X1 - 0.8037X3 + 8.2078X4 - 0.6994X21 - 0.8882X22- 1.5582X23 - 1.1231X1X2 + 2.6225X1X4 - 1.7931X2X3 - 1.6956X2X4- 1.0581X3X4where Y is the objective function (thickness of anodic film), X1 is the current density;X2 is the electrolyte concentration; X3 is the temperature of electrolyte and X4 is theanodizing time.The study shows that the anodizing time and current density had shown positivedependence of great significance on the anodic film thickness while the other twostudied variables (i.e. concentration and temperature of electrolyte) had shown smalldependence on the film thickness of aluminum alloy (6063).Optimum conditions for achieving the maximum film thickness are obtained fromoptimizing the above correlation and are found as follow: 4 A /dm2 Currentdensity, 6 vol. % Acid concentration, 19.5 oC Electrolyte temperature and 60 min.time of anodizing.