PROPERTIES OF Cr-C-Al_2O_3 DEPOSITS PREPARED ON A Cu SUBSTRATE USING Cr~(3+)-BASED PLATING BATHS

摘要

Cr-C-Al_2O_3 deposits with different Al_2O_3 concentrations were successfully prepared on a Cu substrate from Cr~(3+)-based electroplating baths. The microstructures of the Cr-C-Al_2O_3 deposits were examined using optical, scanning, and transmissi on electron microscopes. The hardness values, the corrosion and wear resistance of the Cr-C and Cr-C-Al_2O_3 deposited specimens were evaluated. Based on the experimental results, Al_2O_3 nanoparticles were uniformly distributed within the Cr-C deposits after electroplating in a Cr~(3+)-based plating bath. The hardness values of the Cr-C-Al_2O_3 deposits increased with the Al_2O_3 concentration in the electroplating bath. The corrosion resistance of the Cr-C-deposited specimens could be noticeably improved by adding Al_2O_3 nanoparticles to the deposit. This is attributed to de crease in the number of cracks in the Cr-C specimens codeposited with Al_2O_3 nanoparticles. According to the transmission electron microscopy study, the crack-reduction mechanism in the Cr-C-Al_2O_3 deposits was proposed. The Cr-C-Al_2O_3 deposited specimen, which was prepared in an electroplating bath with an Al_2O_3 concentration of 50 g/L, had a relatively high corrosion resistance compared to the other specimens.