Fabrication of anodic porous alumina for metal-polymer direct joining

Abstract

In order to meet the demand of energy saving, the lighter plastic materials have been widely used to replace the metal parts and one of the popular solutions is metal-polymer joints. The former studies on one of the promising joining methods called injection molded direct joining (IMDJ) indicated that metal pieces with rough surfaces can be joined with polymer directly via typical injection molding. Anodization was applied to fabricate the nanopores with different diameters on the alumina surface for IMDJ. This study focused on the fabrication of anodic pores in different diameters with similar porosity and arrangement in order to evaluate the effect of the anodic pores diameters on the joining strength and polymer replication. Electropolishing process and Two-step anodization was adopted to improve the anodic porosity and order at the electrolyte of Citric acid. The anodic pores diameters were fabricated up to 300 nm and the porosity was improved to be similar to that of anodic pores in 60 nm diameters from Phosphoric acid.