▎ 摘　　要

NOVELTY - Preparing coated silicon nitride composite powder involves using 5-30 wt.% graphene oxide coated silicon nitride, 0.25-5% magnesium oxide, 0.5-5% molybdenum, 0.5-5% nickel, and proper amount of aluminum oxide, where graphene oxide coated silicon nitride is prepared by adding silicon nitride powder to hydrogen peroxide and carrying out oxidation treatment at 60-100 degrees C, then dispersing into aqueous and alcohol mixing solution, adding coupling agent hydrating solution, and using silicon nitride powder as coupling agent with mass concentration of 2.5-10 wt.%, and heating up to 60-90 degrees C. USE - Method for preparing coated silicon nitride composite powder. ADVANTAGE - The method enables to prepare coated silicon nitride composite powder effectively solves graphene oxide and uniform dispersion of nanoparticles in composite ceramic substrate, particle agglomeration and so on caused by generating pores, and also avoids orientation problem of graphene in a ceramic matrix. DETAILED DESCRIPTION - Preparing coated silicon nitride composite powder involves using 5-30 wt.% graphene oxide coated silicon nitride, 0.25-5% magnesium oxide, 0.5-5% molybdenum, 0.5-5% nickel, and proper amount of aluminum oxide, where graphene oxide coated silicon nitride is prepared by adding silicon nitride powder to hydrogen peroxide and carrying out oxidation treatment at 60-100 degrees C, then dispersing into aqueous and alcohol mixing solution, adding coupling agent hydrating solution, and using silicon nitride powder as coupling agent with mass concentration of 2.5-10 wt.%, heating up to 60-90 degrees C, adjusting pH value to 8-10, stirring and reacting to obtain coupling agent surface modified silicon nitride suspension, then adjusting silicon nitride suspension pH value to 3-5, adding graphene oxide aqueous dispersion liquid with pH value of 8-10, and carrying out ultrasonic stirring and standing until the coating particles are precipitating, separating and drying to obtain final product.