Tribological Properties of Magnesium Ion-exchanged α-Zirconium Phosphate as a Solid Lubricant Additive in Lithium Grease

Magnesium ion-exchanged a-zirconium phosphates(Mg-α-ZrP) with particle sizes of 600 and 80 nm were prepared through the sealed ion-exchange and one-step hydrothermal synthesis methods, respectively. It was found that larger particles of Mg-α-ZrP had a higher load-carrying capacity than that of smaller particles, whereas smaller Mg-α-ZrP particles had better anti-wear properties than that of larger Mg-α-ZrP particles under mild loads. The correlation between the particle size of the sample and the surface roughness of the friction pair thus seems to be a key factor influencing the performance.

Dispersion–tribological property relationship in mineral oils containing 2D layered α-zirconium phosphate nanoplatelets

Inorganic nanomaterials exhibit superior friction-reduction and anti-wear properties in oils. In this study, 2D layered α-zirconium phosphate (α-ZrP) nanosheets intercalated with different amines have been synthesized to study their dispersion stabilities in lubricating oil and tribological applications. The intercalated amines should be sufficiently long and lipophilic to provide stabilization to α-ZrP nanosheets in mineral oil. The results of tribological tests illustrate that with the addition of well-dispersed nanosheets, the coefficient of friction (COF) and pin volume loss reduce by ~47% and 75%, respectively. The excellent dispersion stability enables the nanosheets to flow into the contact area at the beginning, and thereby protect the rubbing surface. A reduction in the van der Waals forces between the adjacent layers induced by the intercalated amines transforms the friction between adjacent layers from pin disk to sliding, leading to a decrease in the COF under hydrodynamic lubrication. The study provides a new method to enhance the tribological properties via tuning the dispersion stabilities of nanomaterials in oils.

Synthesis, characterization and antimicrobial activity of zinc and cerium co-doped α-zirconium phosphate

A series of zinc ions or/and cerium ions co-doped a-zirconium phosphate （Zn-Ce@ZrPs） were prepared. The novel Zn-Ce@ZrPs were characterized and the antibacterial activity on Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus were tested. The results showed that zinc ions （Zn2＋） or/and cerium ions （Ce3＋） were combined with ZrP, and the Ce3＋ was adsorbed on the surface of ZrP through hydrogen bonds, while Zn2＋ intercalated into the interlayer of ZrP. Zn-Ce@ZrPs showed excellent synergistic antibacterial activity. When Zn2＋/Ce3＋ atomic ratio was 0.6, the Zn-Ce@ZrP3 showed the highest synergistic antibacterial efficiency, suggesting great potential ap- plication as antibacterial agents in microbial control.

Assembly of exfoliated α-zirconium phosphate nanosheets:Mechanisms and versatile applications

α-Zirconium phosphate(Zr(HPO_(4))_(2)⋅H_(2)O,α-ZrP)is an inorganic layered compound.Since the first report of crystallineα-ZrP in 1964,thanks to its simple synthesis and unique physiochemical properties,α-ZrP has found widespread application in many fields including mechanical reinforcing,barrier improvement,flame retardancy,anticorrosion,catalysis,environment,energy,and medicine.Because of the ease of exfoliation ofα-ZrP to obtain single-layer nanosheets,as well as its rich surface chemistry thanks to the high density of orderly arranged surface acidic hydroxyl groups,α-ZrP single-layer nanosheets are ideal building blocks for self-assembly or assembly with other chemicals.The assembly ofα-ZrP nanosheets could form a randomly dispersed structure(isotropic),roughly ordered structure(nematic),or highly ordered structure(smectic)within liquid colloids or solid hybrids(including hydrogels).Thanks to the combination of the unique structures and the novel functions of the components,the assembled materials have found a wide verity of applications due to their excellent properties.In this article,the methods to synthesizeα-ZrP,the approaches and mechanisms to exfoliateα-ZrP,and the strategies to assembleα-ZrP nanosheets to form various structures,as well as the applications of the assembled materials are reviewed.The emerging prospects ofα-ZrP nanosheets as a key material in next-generation functional applications are envisioned.