The invention relates to a nano 
chromium carbide ferrofluid and a preparation method thereof. High-energy ball milling nano magnetic 
chromium carbide with the particle size between 40nm and 70nm is used as magnetic particles in the 
ferrofluid, the precursor is prepared through an 
aqueous solution batching method, and nano 
chromium carbide is prepared through a direct 
carbonization method of chromium oxides; nano magnetic 
chromium carbide is prepared after high-energy ball milling, nano magnetic 
chromium carbide particles are pre-dispersed in a base solution and subjected to 
surface modification to obtain the nano 
chromium carbide ferrofluid. According to the nano chromium carbide ferrofluid and the preparation method thereof, the nano chromium carbide particle size is between 40nm and 70nm, aggregation is not serious, 
ferromagnetism is provided after high-energy ball milling, the saturated 
magnetization is 26.04 emu / g, the saturated 
magnetic field intensity is 4800 Oe, the nano chromium carbide particles have good 
dispersity and stability in the base solution after 
surface modification, the ferrofluid saturated 
magnetization is 4.32 emu / g, and the ferrofluid can be used for ferrofluid sealing, 
lubrication, damping and the like and can be used in specific environments such as the strong oxidizing environment.