Material Removal Mechanisms of Cu-Co Metal-Powder Composite by Microorganisms

Material characteristics of pure copper, pure cobalt and Cu-Co metal-powder composite were comparative studied through biomachining byAcidithiobacillus ferrooxidans(A. ferrooxidans) in three groups of culture solutions. Material removal mechanisms of Cu-Co metal-powder composite involved in biomachining were explored. It was first observed that the pure cobalt and Cu-Co metal-powder composite were machined by theA. ferrooxidans. The material removal of three workpieces presented linear increase along the machining process due to the metabolic activity of theA. ferrooxidans. Different with the pure metal, the material removal mechanism of Cu-Co metal-powder is explained by the dual effect of micro-galvanic corrosion and participation of Cu(2+)and Fe(3+)for oxidization of cobalt.