Study On Oxidation And Corrosion Resistance Of High-performance Copper Alloys

Copper alloys are widely applied in electrical and electronic industries, because of their excellent electric conductivity, thermal conductivity and machining properties. But copper alloy is easy to be oxidized when use and corroded different level in the atmosphere, which is considered to be an important reason for the invalidation of components. Therefore, oxidation and corrosion resistant properties of the copper alloy caused peoples'wide attention.Five kinds of alloy are studied in this paper. They are Cu-0.8-0.05Y Cu, Cr-1.0-0.05Y Cu. Cr-0.8Cr-0.15Zr-0.05Y. Cu-0.8Cr-0.2Zr-0.05Y, Cu-0.8Cr-0.3Zr-0.05Y (Numbers for1-#5). The research is on the alloys' micro hardness, conductivity and other properties through different deformation and aging treatment. The research is focus on the oxidation characteristics of Cu-Cr-Y and Cu-Cr-Zr-Y alloy, whose deformation is90%. after the aging treatment. The influence of Cr and Zr elements on Cu-0.05Y alloy oxidation characteristics is analyzed. And get some new results in this paper:(1) The dynamic analysis of the two Cu-Cr-Y alloys,1#and2#, oxidized at550℃in latm pure oxygen after7hours show:The weight gain increased with increasing chromium at earlier stage. At the later stage, the different weight gain between the two alloys gradually became small. And the oxidation rate of2#alloy was lower than1#in tendency, benefiting from forming more protective chromia film.(2) The order of three Cu-Cr-Zr-Y alloys (3#-5#) on oxidation resistance is3#>5#>4#.(3) The results of1#and4#alloys oxidized respectively at400℃and550℃in1atm pure oxygen after24hours show that:The oxidation temperature can change the oxidation mechanism of the alloys, conforming linear law in initial stage and parabolic law in later stage when oxidized at400℃, composed of two parabolic stages having different parabolic rate constants at550℃. SEM observation shows the films of the two alloys are both composed by the outer layer of CuO and the inner layer of Cu2O. But the additional of Zr can change the microstructure of the oxidation film. It is equiaxial crystal for1#and columnar crystal for4#.(4) The corrosion resistance order of the alloys in NaCl (1mol/L) solution is:4#>1#>2#.(5) The alloys with excellent conductivity, large hardness and antioxidant. performances in this experiment condition are available by the heat treatment condition as follows:1#alloy was aged at480℃for30minutes and its conductivity is86.8IACS%, hardness is167Hv:4#alloy was aged at500℃for60minutes and its conductivity is83.3IACS%. hardness is194Hv.