Tribological chemistry of Ti₃SiC₂/Si₃N₄ tribopair in two low-viscosity fluids (water and ethanol) was investigated. The chemical compositions of worn surfaces and friction media were determined by X-ray photoelectron spectroscope and Fourier transform infrared spectroscopy. Results show that the friction and wear of Ti₃SiC₂/Si₃N₄ tribopair in water was moderate while that in ethanol was low. Mechanical wear characterized by pullout of Ti₃SiC₂ grains was responsible for high coefficient offriction and wear rate. Inethanol, tribochemical products, i.e., colloid silicic acid from Ti₃SiC₂ and silicon alkoxide and amines from Si₃N₄ dissolved in the friction liquid and were responsible for low coefficient of friction and wear rates.