New Method of Obtaining a Multilayer Anodized Film on 7075-T6 Al-Alloy Surface

Abstract

It is well known that the anodized thin layer formed on Al-alloys surface are characterized with porosity of nanometric dimensions whatever acid or alkaline solutions are used. In this study, an attempt was made for the first time to develop a new method for obtaining anodized multilayer film by reinforcing the anodized oxide coating with incorporating nanosized graphite in the layer structure during anodizing process by means of anodizing Al- Alloy type 7075 T-6 in an electrolyte composed of water solution of chromic acid and graphite . This leads to obtain a multilayer anodized film having good thickness and high micro hardness properties. Nanosized particles of graphite have been formed into anodic oxide layer. The influence of anodizing process parameters (voltage and current density) on the thickness micro hardness and chemical composition of a multilayer oxide film are determined.