ABSTRACT
The present work aims to investigate the high-temperature tribological performance of Ni-B-W coating. Ni-B-based ternary coating with co-deposition of W has been considered in an attempt to achieve higher, hardness, wear resistance, and enhanced friction performance. The coatings were deposited autocatalytically on steel substrate from a sodium borohydride-based alkaline bath. Ni-B-W coatings in heat-treated form (350°C for 1 hour) were subjected to tribo-tests on a pin-on-disc tribometer. Applied normal load, sliding speed and operating temperature 240was varied at three equally spaced levels within 10–30 N, 0.25–0.42 m/s and 100–500°C, respectively. To improve process capability, perform statistical analysis and draw significant conclusions, Taguchi’s L27 orthogonal array was adopted to perform experiments. Tribological responses considered were mass loss (signifying wear) and coefficient of friction (COF). Grey relational analysis was implemented to optimize the tribo-test parameters. The objective was to minimize mass loss and COF simultaneously. Optimum mass loss and COF was achieved at 10 N load, 0.25 m/s speed and 500°C operating temperature. Operating temperature was concluded to be of the highest significance in controlling the tribobehavior of the coatings from analysis of variance (ANOVA). Also, proper coating deposition was ensured by characterizing them using various techniques such as energy dispersive spectroscopy, X-ray diffraction and field emission scanning electron microscope (FESEM).
