Water-based lubrication of niobium nitride

Abstract

Water-based lubrication has attracted wide attention as an oil-free lubrication method owing to its greener and cleaner lubrication means. However, due to operating in the water environment, most moving parts would inevitably suffer from abrasion, rusting, and aging problems. Developing a novel solid-water composite system with ultra-low friction and wear will open new possibilities for innovative lubrication material research and development. Here, we first revealed the water-based lubrication behavior of a high-hardness niobium nitride coating (NbN). In a three-phase contact environment (water, air, and NbN), oxidation and hydrolytic reactions of NbN result in the formation of “colloidal solutions”, containing Nb2O5 colloidal particles between the tribo-pairs. Utilizing the double electric layer repulsion and weak shear action of the “colloidal solution”, NbN achieves ultra-low friction and wear; the corresponding values are as low as 0.058 and 1.79 × 10−10 mm3·N−1·m−1, respectively. In addition, other VB transition metal nitrides (VB TMNs) exhibit the same low friction feature as NbN in the three-phase contact environment; the friction coefficients are even lower than those in an oil-based environment. The water-based lubrication of VB TMNs provides a new reliable scheme for optimizing solid-water composite lubrication systems without additives and is expected to be applied in environments with high humidity or insufficient water coverage.

Magnetron Sputtered Thin Films Based on Transition Metal Nitride: Structure and Properties

“…There were some experimental studies that resulted in the similar data as shown in Figure 23. [ 190,194,195 ]…”

“…In this regard, the authors suggested that nitrides of group 5B elements of the periodic table such VN, NbN, and TaN could serve as a nonadditive water–solid composite advanced lubricating materials due to their low friction and wear rate. [ 195 ]…”

“…There were some experimental studies that resulted in the similar data as shown in Figure 23. [190,194,195] A recent work carried out with an aim to prepare "oil free" water-based lubrication of NbN films (using magnetron sputtering) for a clean and green environment. However, the problem is to control the rust, abrasion, and aging-related surface issues.…”

Exploring the frictional characteristics of kelp liquid as an environmentally friendly lubricant

“…Water-based lubricants can reduce friction effectively between workpieces, reduce machine wear, save energy and improve machine efficiency. It is one of the most promising lubricants today (Deng et al , 2016; Miao et al , 2021). Vegetable oil is a potential environmentally friendly metal cutting fluid, which is harmless to the human body and solves a series of health problems caused by synthetic cutting fluids (R et al , 2021).…”

High-temperature wear mechanisms of TiNbWN films: Role of nanocrystalline oxides formation

“…The TiNbWN thin film can be described as a TiN-type single fcc phase (PDF#28-1420), in which the Nb and W atoms occupy the Ti sites. The fact that the TiNbWN film contains a single solution phase can be supported by the structural similarities of the binary nitrides of TiN, NbN, and γWN, which exhibit the same fcc phase with rather similar lattice parameters (a (TiN) = ~0.42 nm, a (NbN) = ~0.44 nm, and a (γWN) = ~0.41 nm)[45][46][47]. The characteristic peaks in the XRD pattern slightly deviated to smaller values compared with that of the TiN phase, indicating that the interplanar spacing of the fcc solution in the TiNbWN thin film was increased by dissolving Nb and W. The strongest peak corresponded to the (111) crystallographic plane, implying the preferred growth of the film deposited.…”