Effect of SiC and Al2O3 particles on the electrodeposition of Zn, Co and ZnCo: II. Electrodeposition in the presence of SiC and Al2O3 and production of ZnCo–SiC and ZnCo–Al2O3 coatings

SiC or Al 2 O 3 microsized particles were added to acid sulfate-based solutions for the electrodeposition of Zn, Co, and ZnCo. Initially, their effects on the electrochemical processes were evaluated. The Zn electrodeposition rate was increased in both SiC and Al 2 O 3 -loaded solutions. The Co electrodeposition rate was also increased by SiC. However, Al 2 O 3 decreased it, especially at the beginning. Both SiC and Al 2 O 3 influenced the electrodeposition of ZnCo positively at moderate loadings. The factors involved in producing ZnCo–SiC and ZnCo–Al 2 O 3 composites were evaluated. ZnCo–SiC composites could be deposited with a higher [Co/Zn] ratio in the metal matrix than for pure ZnCo. In ZnCo–Al 2 O 3 , the [Co/Zn] ratio was smaller than in ZnCo and ZnCo–SiC. It was necessary to reduce the CoSO 4 concentration to improve the Al 2 O 3 co-deposition. The variation in [Co/Zn] ratio could, in principle, be related to the effects of SiC and Al 2 O 3 on the individual Zn and Co electrodeposition.