Effects of oxygen contents in copper on the diffusion interface of copper/steel

The formation and influence factors of oxide near the interface of copper/steel bi-metal bar through diffusing process were analyzed by means of SEM,XRD and EPMA.Two kinds of different oxygen concentration copper bar were used in the tests.The results indicate that the oxide is not formed in oxygen-free copper even if the diffusion time is very long.The dispersed oxide near the interface in the side of copper is formed because of higher oxygen content in oxygen-bearing copper.The size of oxide increases dramatically with increasing diffusion temperature and prolonging diffusion time and the dispersed zone becomes larger.The fracture near the interface occurs and spreads along the oxide.The oxide is Fe_2O_3 according to the results of SEM observation and EPMA.The formation of oxide is discussed by thermodynamics analysis.