Hardness of oxide films formed as a result of aluminium anode oxidation processes

Factors that influence the anode oxidation processes of aluminium and its alloys are discussed. The main parameters involved in such processes have been selected and subjected to measurement under controlled experimental conditions. The effects of the variation of the chemical, electrical and thermal parameters of the aluminium anode oxidation process on the hardness level of the resulting oxide layer have been studied. In order to quantify the relationships that govern the kinetics of the anode oxidation process, these data were subjected to analysis employing a central compositional rotatory programming matrix. Parameters employed were electrolyte concentration, temperature, current density and immersion time of the product in the electrolyte to achieve a desired oxide layer. The hardness of the resulting oxide layers is discussed.