Tribological and corrosion performance of duplex electrodeposited Ni-P/Ni-W-P coatings

The present research investigates the properties of duplex electrodeposited Ni-P/Ni-W-P coatings consisting of Ni-P and Ni-W-P as inner layers alternately. This study aims to examine how various heat treatment conditions affect the mechanical, tribological, and electrochemical properties of the coatings.The results show that the heat treatment temperature and duration have a profound influence on the coating's microstructure, which significantly affects its overall performance. Optimal microhardness and lower wear rates are observed at 400 degrees C temperature for 1 h duration. However, at 800 degrees C for 4 h, duplex electrodeposited coatings display cracks and increased oxide layers, negatively impacting mechanical, tribological, and corrosion properties. The Ni-W-P outer layer coating exhibited higher hardness and a lower wear rate compared to the Ni-P outer layer coatings. However, the assessment of corrosion behavior shows that Ni-P offers increased corrosion resistance, largely due to its ability to form a passive layer, which is further enhanced after heat treatment. When compared to their individual single-layer coatings, the present duplex coatings demonstrate superior overall performance.