▎ 摘　　要

NOVELTY - Lubricating oil composite additive comprises modified nano-diamond and graphene modified, where modified graphene forms double-layer structure, modified nano-diamond is located in double-layer structure to form sandwich layer structure. The surface of modified nano-diamond is grafted with positively charged group of modified nano diamond. The graphene single side is grafted with negatively charged groups of graphene. USE - Lubricating oil composite additive. ADVANTAGE - The lubricating oil composite additive has stable dispersion, improves friction performance and abrasion resistance of lubricating oil, and prolongs replacement period of the lubricating oil. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing lubricating oil composite additive, which involves: (A) grafting nano diamond surface with positive electricity group to obtain modified nano diamond; (B) adding modified nano-diamond in the first solvent to obtain modified nano diamond dispersion; (C) single-side grafting of graphene with negative radical to obtain modified graphene; (D) dispersing modified graphene in second solvent to obtain modified graphene dispersion liquid; and (E) adding modified nano-diamond dispersion with modified graphene dispersion, modified nano-diamond side with negative radical to graphene, subjecting to electrostatic attraction to form sandwich layer structure, then filtering, centrifuging, and drying to obtain complex phase of lubricating oil composite additive.