Tribological properties of Ni-BP/Ni coatings produced by electroless co-deposition

Abstract

In the field of tribology, black phosphorus (BP) with a layered structure has displayed outstanding performance. To alleviate the high friction and corrosive wear of the friction pairs of marine equipment, four types of coatings including Ni-PP, Ni-BP/Ni30, Ni-BP/Ni60, and Ni-BP/Ni90, which were labelled with different deposition time, were prepared on Q235 steel via electroless co-deposition technique. A ball-on-disk reciprocating tribometer was used to evaluate their tribological properties in 3.5 wt% NaCl, poly-α-olefin 6 (PAO6), and deionized water, respectively. The results show that the Ni-BP/Ni coatings sliding in 3.5 wt% NaCl exhibited better friction reduction and wear resistance than that in deionized water. The Ni-BP/Ni30 coating sliding in 3.5 wt% NaCl showed excellent tribological properties and compared with the Ni-P coating, its average friction coefficient was reduced by 40 % at a load of 4 N and the wear scar cross-sectional area was reduced by 77 % at a load of 10 N. The enhanced tribological properties were attributed to the lamellar slip of BP nanosheets and the formation of a tribofilm composed of NiO, Ni(OH)2, and SiO bonds and an adsorbed film with BP nanosheets. The Ni-BP/Ni coatings present a promising application in seawater corrosive environment.