Effect of trimethylamine borane (TMAB) bath concentration on electrodeposited Ni-B/TiC nanocomposite coatings

Abstract

In this study, stainless steel material was coated with Ni-B alloy-based, TiC particle reinforced composite film using electrochemical deposition method. The properties of the obtained Ni-B/TiC nanocomposite coatings were investigated in terms of the effect of trimethylamine borane (TMAB) bath concentration, which is a boron source. In addition, the data of pure Ni, Ni-B alloy and stainless steel are presented together for comparison. According to the cyclic voltammogram (CV) analysis, it is seen that TMAB contributes to increasing the deposition rate. In the crystal structure analysis, the effect of TMAB was weaker at low TiC bath concentrations, while the effect of TMAB was more dominant at high TiC bath contents. The crystal grain size values of nanocomposite coatings vary between 5.8 and 16.8 nm, and these values decrease up to 86% when compared to the crystal grain size of the pure Ni coating. Although the increase in TMAB initially causes an increase in the microhardness of nanocomposite coatings, when the TMAB value was further increased, it was observed that the microhardness decreased even more compared to the previous initial value. The highest hardness value was obtained in the sample produced at 5 g/l TiC and 6 g/l TMAB bath contents, and this value was 817 HV. Compared to this value, it was observed that the hardness of pure Ni was 65% lower. It was observed that TMAB did not have significant effect on the coating morphology, but the increase in TMAB caused an increase B content and a decrease in the TiC content in the nanocomposite coating. Furthermore, it was revealed that the increase in TMAB bath concentration caused an improvement on corrosion resistance. The corrosion current of the composite sample with 9 g/l TMAB concentration, which showed the best corrosion performance, decreased by 85% compared to pure nickel.