Preparation Of Nanoporous Copper And The Formation Mechanism Research

Nanoporous metals are new engineering materials,which have both functionaland structuraladvantages over traditional metals,in that they have large surface areas,chemical stability andhigh yield strength.They are of potential use in numerous applications such as catalysts，sensors，actuators,heat-exchanger and so on. Nanoporous copper （NPC） can be synthesizedby free corrosion dealloying with rapid quenched Al-Cu and Mg-Cu alloy. The phases andmicrostructure of samples were analyzed by XRD, SEM. The effect of dealloying parameters,which include the electrolyte component, temperature and time of dealloying, on the residualAl content and micro-morphology of nanoporous Cu was investigated.The results indicate that:In the present work，it has been found that （NPC） can be fabricated through chemieal orelectrochemical dealloying of rapidly solidified Mg-Cu and Al-Cu alloys.The results indicate that the four Al-Cu alloys can dealloying in corrosion solution. Theexperimental results of chemieal dealloying of these Al-Cu alloys show that bicontinuousligament structures nanoporous Cu can be obtained by the dealloying of the three Al-Cualloys(Al₆₇Cu₃₃，Al₆₂Cu₃₈and Al₅₇Cu₄₃) in corrosion solution,except for the Al₅₀Cu₅₀，whichis composed of a single AlCu phase.The pore shape grows from bicontinuous ligamentstructures with prolonging the corrosion time.Then with the continually increased corrosiontime, the pore wall becomes coarse gradually. The synergetic dealloying of Al₂Cu and AlCuin the two-phase Al-Cu alloys results in the morphologies of NPC with bicontinuous ligamentstructure.The experimental results of chemieal dealloying of these Mg-Cu alloys show thatnanoporous Cu can be obtained by the dealloying of the four Mg-Cualloys(Mg₆₇Cu₃₃,Mg₆₀Cu₄₀,Mg₅₀Cu₅₀and Mg₄₀Cu₆₀) in corrosion solution,except for theMg₃₃Cu₆₇alloy，which is composed of a single MgCu₂phase. With the continually increasedcorrosion time and temperature, the pore wall becomes coarse gradually.Bicontinuouligament-channel nanostructures can be obtained from whether the single-phase Mg-Cu alloycomposed of Mg₂Cu phase or the two-phase alloy composed of Mg₂Cu and MgCu₂phase.Moreover,The results indicate that the Mg₂Cu and MgCu₂phase have different corrosionmechanism.The dealloying of MgCu₂phase is more difficult and complicated than that ofMg₂Cu Phase.Furthermore,the less noble Mg₂Cu phase shows a significant promoting effecton the dealloying of the more noble MgCu₂phase. With the increased MgCu₂phase,the dealloying is difficult to continue.For dual-phase alloy,the phase composition of alloy has agreater impact on its dealloying,the two phase content and electrochemical properties ofdual-phase alloy need have bigger difference.