▎ 摘　　要

NOVELTY - Graphene-based calcium carbonate nanocomposition comprises graphene oxide nano calcium carbonate, nitrogen-doped graphene oxide nano calcium carbonate, fluorine doped graphene oxide nano calcium carbonate, where the graphene oxide, the nitrogen-doped graphene oxide, and the fluorine-doped graphene oxide content are 0.78 wt.%, 1.56 wt.%, 3.125 wt.%, and 6.25 wt.% of the graphene-based calcium carbonate nanocomposition. USE - The graphene-based calcium carbonate nanocomposition is useful for grease (claimed). ADVANTAGE - The nanocomposition: reduces the friction coefficient i.e. the friction coefficient in the running-in stage, improves the friction-reducing performance of the grease; and the preparation method: is simple and easy, the reaction condition is mild, and is economical. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing the graphene-based calcium carbonate nanocomposition, comprising (i) digesting 2-10 g calcium oxide with 100 ml twice-distilled water at 80 degrees C to obtain suspended calcium hydroxide, aging by overnight, adding 0-30 ml of 0.05-0.5 mol/l lauric acid/ethanol solution, stir ring and reacting at room temperature for 2 hours, then passing the carbon dioxide gas at a rate of 0.2-1.5 l/minute in a constant temperature water bath for carbonization, where the pH meter keeps track of the pH change of the reaction solution, and stopping the reaction when the pH is 7, filtering the product, washing and vacuum drying at 60 degrees C to obtain a nano calcium carbonate product; (ii) dispersing prepared 240-1920 mg nano calcium carbonate in 240 ml absolute ethanol, performing ultrasonic dispersion at 400 W for 1 hour to obtain a uniform dispersion of nano calcium carbonate dispersion at the concentration of 1-8 mg/ml; (iii) accurately adding 24-120 mg graphene oxide or nitrogen-doped graphene oxide or fluorine-doped graphene oxide, dispersing in 120 ml water, performing ultrasonic dispersion at 400 W for 2 hours, performing glass rod assisted stirring at the concentration of 0.2-1 mg/ml, storing in refrigerator at 4 degrees C; (iv) taking 7.5 ml, 15 ml, 30 ml, 60 ml graphene-based dispersion of the step (iii), respectively adding to 240 ml nano-calcium carbonate dispersion of the step (ii), and soaking for 360 hours at room temperature for 0.5 hour, then centrifuging at high speed and separating, drying the product at 60 degrees C for 18 hours to obtain graphene oxide or nitrogen-doped graphene oxide or fluorine-doped graphene oxide content of 0.78 wt.%, 1.56 wt.%, 3.125 wt.%, 6.25 wt.% of graphene calcium carbonate nanocomposition.