From ultra-low friction to superlubricity state of black phosphorus:Enabled by the critical oxidation and load  

作　　者：Qiang LI Fenghua SU Yanjun CHEN Jianfang SUN 

机构地区：[1]School of Mechanical&Automotive Engineering,South China University of Technology,Guangzhou 510641,China [2]Guangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced Manufacturing,South China University of Technology,Guangzhou 510640,China

出　　处：《Friction》2023年第10期1829-1844,共16页摩擦（英文版）

基　　金：The authors were grateful to the financial support from the National Natural Science Foundation of China(52175168);the Natural Science Foundation of Guangdong Province(2021A1515012266),China;Guangdong Basic and Applied Basic Research Foundation(2022A1515010513),China.

摘　　要：Based on the density functional theory(DFT),we investigate the friction properties of inevitable oxidized black phosphorus(o-BP).o-BP with the weaker interlayer adhesion exhibits their great potential as a solid lubricant.At the zero load,the friction property of o-BP is adjusted by its oxidation degree.Expressly,ultra-low friction of P4O2(50%oxidation,O:P=2:4=50%)is obtained,which is attributed to the upper O atoms with lower sliding resistance in the O channel formed by lower layer O atoms.More attractive,we observe superlubricity behavior of o-BP at the critical load/distance due to the flattening potential energy surface(PES).The flattening PES is controlled by the electrostatic role for the high-load(P4O3,O:P=3:4=75%),and by the electrostatic and dispersion roles for the low-load(P4O2).Distinctly,the transform from ultra-low friction to superlubricity state of black phosphorus(BP)can be achieved by critical oxidation and load,which shows an important significance in engineering application.In addition,negative friction behavior of o-BP is a general phenomenon(Z>Z_(min),Z_(min)is the interlayer distances between the outermost P atoms of minimum load.),while its surface-surface model is different from the fold mechanism of the tip-surface model(Z_(0)<Z<Z_(min),Z_(0)is the interlayer distances between the outermost P atoms of equilibrium state.).Thus,this phenomenon cannot be captured due to the jump effect with instability of the atomic force microscopy(AFM)(Z>Z_(min)).In summary,o-BP improves the friction performance and reduces the application limitation,comparing to graphene(Gr),MoS2,and their oxides.

关 键 词：oxidized black phosphorus(o-BP) ultra-low friction SUPERLUBRICITY critical load/distance FIRST-PRINCIPLES 

分 类 号：O313.5[理学—一般力学与力学基础]