Increasing the Wear and Corrosion Resistance of Cu-Deposited Magnesium Alloy with Electroplating Cr (III), Cr (III) Based Alloy, and Cr(III) Based Composite Deposits

Because of having low density and high specific strength, Mg alloys have been used as the construction materials for 3C products, automobile industry, and leasure products etc. However, Mg alloys are active in various environment and have poor corrosion resistance, so surface treatments of Mg alloys for anti-corrosion are needed in applications. The applicant of this project has developed an environment-friendly copper electroplating bath for Cu electrodeposition on the Mg alloy components (AZ31, AZ61, and AZ91) and the method have been applied for Taiwan’s and USA’s patents. Moreover, the experimental results have been published in Corrosion Science and Electrochimica Acta. Based on our experimental results, in this three-year project, the Cu deposited Mg alloy specimens will be further electroplated with a protective Cr(III), Cr(III) based alloy, and Cr(III) based composite deposits to increase their corrosion and wear resistance. The electroplating is conducted in an electrochemical three-electrode cell. The electroplating cell and testing specimens will be prepared. The surface morphologies of deposited Mg specimens will be examined with atomic force microscope, surface profiler and scanning electron microscope. The microstructures of the deposited Mg alloy specimens will be studied with x-ray diffractrometer, optical, scanning electron and transmission electron microscopies. The mechanical properties will be evaluated with micro-hardness test, pin-on-disc wear resistance test. The corrosion resistance of the deposited Mg alloy specimens will be measured with electrochemical three-electrode cell, in which their anodic polarization behavior in a selected solution could be studied. Based our experimental results of trivalent chromium and copper electrodeposition, a protective deposit for Mg alloy specimen will be developed without difficulty and the results can be expected. We plan publish at least two articles per year and two innovation patents after conducting this three-year project.

Project ID:PB9807-2066
External Project ID:NSC98-2221-E182-016-MY3